consistent target

* fix(subflows): tag dropdown + resolution logic

* fixes;

* revert parallel change

apps/sim/app/api/function/execute/route.test.ts

@@ -313,7 +313,7 @@ describe('Function Execute API Route', () => {
           'block-2': 'world',
         },
         blockNameMapping: {
-          validVar: 'block-1',
+          validvar: 'block-1',
           another_valid: 'block-2',
         },
       })
@@ -539,7 +539,7 @@ describe('Function Execute API Route', () => {
           'block-complex': complexData,
         },
         blockNameMapping: {
-          complexData: 'block-complex',
+          complexdata: 'block-complex',
         },
       })
 

apps/sim/app/api/function/execute/route.ts

@@ -6,11 +6,11 @@ import { executeInE2B } from '@/lib/execution/e2b'
 import { executeInIsolatedVM } from '@/lib/execution/isolated-vm'
 import { CodeLanguage, DEFAULT_CODE_LANGUAGE, isValidCodeLanguage } from '@/lib/execution/languages'
 import { escapeRegExp, normalizeName, REFERENCE } from '@/executor/constants'
+import { type OutputSchema, resolveBlockReference } from '@/executor/utils/block-reference'
 import {
   createEnvVarPattern,
   createWorkflowVariablePattern,
 } from '@/executor/utils/reference-validation'
-import { navigatePath } from '@/executor/variables/resolvers/reference'
 export const dynamic = 'force-dynamic'
 export const runtime = 'nodejs'
 
@@ -470,14 +470,17 @@ function resolveEnvironmentVariables(
 
 function resolveTagVariables(
   code: string,
-  blockData: Record<string, any>,
+  blockData: Record<string, unknown>,
   blockNameMapping: Record<string, string>,
-  contextVariables: Record<string, any>
+  blockOutputSchemas: Record<string, OutputSchema>,
+  contextVariables: Record<string, unknown>,
+  language = 'javascript'
 ): string {
   let resolvedCode = code
+  const undefinedLiteral = language === 'python' ? 'None' : 'undefined'
 
   const tagPattern = new RegExp(
-    `${REFERENCE.START}([a-zA-Z_][a-zA-Z0-9_${REFERENCE.PATH_DELIMITER}]*[a-zA-Z0-9_])${REFERENCE.END}`,
+    `${REFERENCE.START}([a-zA-Z_](?:[a-zA-Z0-9_${REFERENCE.PATH_DELIMITER}]*[a-zA-Z0-9_])?)${REFERENCE.END}`,
     'g'
   )
   const tagMatches = resolvedCode.match(tagPattern) || []
@@ -486,41 +489,37 @@ function resolveTagVariables(
     const tagName = match.slice(REFERENCE.START.length, -REFERENCE.END.length).trim()
     const pathParts = tagName.split(REFERENCE.PATH_DELIMITER)
     const blockName = pathParts[0]
+    const fieldPath = pathParts.slice(1)
 
-    const blockId = blockNameMapping[blockName]
-    if (!blockId) {
+    const result = resolveBlockReference(blockName, fieldPath, {
+      blockNameMapping,
+      blockData,
+      blockOutputSchemas,
+    })
+
+    if (!result) {
       continue
     }
 
-    const blockOutput = blockData[blockId]
-    if (blockOutput === undefined) {
-      continue
-    }
-
-    let tagValue: any
-    if (pathParts.length === 1) {
-      tagValue = blockOutput
-    } else {
-      tagValue = navigatePath(blockOutput, pathParts.slice(1))
-    }
+    let tagValue = result.value
 
     if (tagValue === undefined) {
+      resolvedCode = resolvedCode.replace(new RegExp(escapeRegExp(match), 'g'), undefinedLiteral)
       continue
     }
 
-    if (
-      typeof tagValue === 'string' &&
-      tagValue.length > 100 &&
-      (tagValue.startsWith('{') || tagValue.startsWith('['))
-    ) {
-      try {
-        tagValue = JSON.parse(tagValue)
-      } catch {
-        // Keep as-is
+    if (typeof tagValue === 'string') {
+      const trimmed = tagValue.trimStart()
+      if (trimmed.startsWith('{') || trimmed.startsWith('[')) {
+        try {
+          tagValue = JSON.parse(tagValue)
+        } catch {
+          // Keep as string if not valid JSON
+        }
       }
     }
 
-    const safeVarName = `__tag_${tagName.replace(/[^a-zA-Z0-9_]/g, '_')}`
+    const safeVarName = `__tag_${tagName.replace(/_/g, '_1').replace(/\./g, '_0')}`
     contextVariables[safeVarName] = tagValue
     resolvedCode = resolvedCode.replace(new RegExp(escapeRegExp(match), 'g'), safeVarName)
   }
@@ -537,18 +536,27 @@ function resolveTagVariables(
  */
 function resolveCodeVariables(
   code: string,
-  params: Record<string, any>,
+  params: Record<string, unknown>,
   envVars: Record<string, string> = {},
-  blockData: Record<string, any> = {},
+  blockData: Record<string, unknown> = {},
   blockNameMapping: Record<string, string> = {},
-  workflowVariables: Record<string, any> = {}
-): { resolvedCode: string; contextVariables: Record<string, any> } {
+  blockOutputSchemas: Record<string, OutputSchema> = {},
+  workflowVariables: Record<string, unknown> = {},
+  language = 'javascript'
+): { resolvedCode: string; contextVariables: Record<string, unknown> } {
   let resolvedCode = code
-  const contextVariables: Record<string, any> = {}
+  const contextVariables: Record<string, unknown> = {}
 
   resolvedCode = resolveWorkflowVariables(resolvedCode, workflowVariables, contextVariables)
   resolvedCode = resolveEnvironmentVariables(resolvedCode, params, envVars, contextVariables)
-  resolvedCode = resolveTagVariables(resolvedCode, blockData, blockNameMapping, contextVariables)
+  resolvedCode = resolveTagVariables(
+    resolvedCode,
+    blockData,
+    blockNameMapping,
+    blockOutputSchemas,
+    contextVariables,
+    language
+  )
 
   return { resolvedCode, contextVariables }
 }
@@ -585,6 +593,7 @@ export async function POST(req: NextRequest) {
       envVars = {},
       blockData = {},
       blockNameMapping = {},
+      blockOutputSchemas = {},
       workflowVariables = {},
       workflowId,
       isCustomTool = false,
@@ -601,20 +610,21 @@ export async function POST(req: NextRequest) {
       isCustomTool,
     })
 
-    // Resolve variables in the code with workflow environment variables
+    const lang = isValidCodeLanguage(language) ? language : DEFAULT_CODE_LANGUAGE
+
     const codeResolution = resolveCodeVariables(
       code,
       executionParams,
       envVars,
       blockData,
       blockNameMapping,
-      workflowVariables
+      blockOutputSchemas,
+      workflowVariables,
+      lang
     )
     resolvedCode = codeResolution.resolvedCode
     const contextVariables = codeResolution.contextVariables
 
-    const lang = isValidCodeLanguage(language) ? language : DEFAULT_CODE_LANGUAGE
-
     let jsImports = ''
     let jsRemainingCode = resolvedCode
     let hasImports = false
@@ -670,7 +680,11 @@ export async function POST(req: NextRequest) {
         prologue += `const environmentVariables = JSON.parse(${JSON.stringify(JSON.stringify(envVars))});\n`
         prologueLineCount++
         for (const [k, v] of Object.entries(contextVariables)) {
-          prologue += `const ${k} = JSON.parse(${JSON.stringify(JSON.stringify(v))});\n`
+          if (v === undefined) {
+            prologue += `const ${k} = undefined;\n`
+          } else {
+            prologue += `const ${k} = JSON.parse(${JSON.stringify(JSON.stringify(v))});\n`
+          }
           prologueLineCount++
         }
 
@@ -741,7 +755,11 @@ export async function POST(req: NextRequest) {
       prologue += `environmentVariables = json.loads(${JSON.stringify(JSON.stringify(envVars))})\n`
       prologueLineCount++
       for (const [k, v] of Object.entries(contextVariables)) {
-        prologue += `${k} = json.loads(${JSON.stringify(JSON.stringify(v))})\n`
+        if (v === undefined) {
+          prologue += `${k} = None\n`
+        } else {
+          prologue += `${k} = json.loads(${JSON.stringify(JSON.stringify(v))})\n`
+        }
         prologueLineCount++
       }
       const wrapped = [

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/action-bar/action-bar.tsx

@@ -151,6 +151,29 @@ export const ActionBar = memo(
           </Tooltip.Root>
         )}
 
+        {isSubflowBlock && (
+          <Tooltip.Root>
+            <Tooltip.Trigger asChild>
+              <Button
+                variant='ghost'
+                onClick={(e) => {
+                  e.stopPropagation()
+                  if (!disabled) {
+                    collaborativeBatchToggleBlockEnabled([blockId])
+                  }
+                }}
+                className={ACTION_BUTTON_STYLES}
+                disabled={disabled}
+              >
+                {isEnabled ? <Circle className={ICON_SIZE} /> : <CircleOff className={ICON_SIZE} />}
+              </Button>
+            </Tooltip.Trigger>
+            <Tooltip.Content side='top'>
+              {getTooltipMessage(isEnabled ? 'Disable Block' : 'Enable Block')}
+            </Tooltip.Content>
+          </Tooltip.Root>
+        )}
+
         {!isStartBlock && !isResponseBlock && (
           <Tooltip.Root>
             <Tooltip.Trigger asChild>
@@ -222,29 +245,6 @@ export const ActionBar = memo(
           </Tooltip.Root>
         )}
 
-        {isSubflowBlock && (
-          <Tooltip.Root>
-            <Tooltip.Trigger asChild>
-              <Button
-                variant='ghost'
-                onClick={(e) => {
-                  e.stopPropagation()
-                  if (!disabled) {
-                    collaborativeBatchToggleBlockEnabled([blockId])
-                  }
-                }}
-                className={ACTION_BUTTON_STYLES}
-                disabled={disabled}
-              >
-                {isEnabled ? <Circle className={ICON_SIZE} /> : <CircleOff className={ICON_SIZE} />}
-              </Button>
-            </Tooltip.Trigger>
-            <Tooltip.Content side='top'>
-              {getTooltipMessage(isEnabled ? 'Disable Block' : 'Enable Block')}
-            </Tooltip.Content>
-          </Tooltip.Root>
-        )}
-
         <Tooltip.Root>
           <Tooltip.Trigger asChild>
             <Button

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/tag-dropdown/tag-dropdown.tsx

@@ -1312,15 +1312,16 @@ export const TagDropdown: React.FC<TagDropdownProps> = ({
     if (currentLoop && isLoopBlock) {
       containingLoopBlockId = blockId
       const loopType = currentLoop.loopType || 'for'
-      const contextualTags: string[] = ['index']
-      if (loopType === 'forEach') {
-        contextualTags.push('currentItem')
-        contextualTags.push('items')
-      }
 
       const loopBlock = blocks[blockId]
       if (loopBlock) {
         const loopBlockName = loopBlock.name || loopBlock.type
+        const normalizedLoopName = normalizeName(loopBlockName)
+        const contextualTags: string[] = [`${normalizedLoopName}.index`]
+        if (loopType === 'forEach') {
+          contextualTags.push(`${normalizedLoopName}.currentItem`)
+          contextualTags.push(`${normalizedLoopName}.items`)
+        }
 
         loopBlockGroup = {
           blockName: loopBlockName,
@@ -1328,21 +1329,23 @@ export const TagDropdown: React.FC<TagDropdownProps> = ({
           blockType: 'loop',
           tags: contextualTags,
           distance: 0,
+          isContextual: true,
         }
       }
     } else if (containingLoop) {
       const [loopId, loop] = containingLoop
       containingLoopBlockId = loopId
       const loopType = loop.loopType || 'for'
-      const contextualTags: string[] = ['index']
-      if (loopType === 'forEach') {
-        contextualTags.push('currentItem')
-        contextualTags.push('items')
-      }
 
       const containingLoopBlock = blocks[loopId]
       if (containingLoopBlock) {
         const loopBlockName = containingLoopBlock.name || containingLoopBlock.type
+        const normalizedLoopName = normalizeName(loopBlockName)
+        const contextualTags: string[] = [`${normalizedLoopName}.index`]
+        if (loopType === 'forEach') {
+          contextualTags.push(`${normalizedLoopName}.currentItem`)
+          contextualTags.push(`${normalizedLoopName}.items`)
+        }
 
         loopBlockGroup = {
           blockName: loopBlockName,
@@ -1350,6 +1353,7 @@ export const TagDropdown: React.FC<TagDropdownProps> = ({
           blockType: 'loop',
           tags: contextualTags,
           distance: 0,
+          isContextual: true,
         }
       }
     }
@@ -1363,15 +1367,16 @@ export const TagDropdown: React.FC<TagDropdownProps> = ({
       const [parallelId, parallel] = containingParallel
       containingParallelBlockId = parallelId
       const parallelType = parallel.parallelType || 'count'
-      const contextualTags: string[] = ['index']
-      if (parallelType === 'collection') {
-        contextualTags.push('currentItem')
-        contextualTags.push('items')
-      }
 
       const containingParallelBlock = blocks[parallelId]
       if (containingParallelBlock) {
         const parallelBlockName = containingParallelBlock.name || containingParallelBlock.type
+        const normalizedParallelName = normalizeName(parallelBlockName)
+        const contextualTags: string[] = [`${normalizedParallelName}.index`]
+        if (parallelType === 'collection') {
+          contextualTags.push(`${normalizedParallelName}.currentItem`)
+          contextualTags.push(`${normalizedParallelName}.items`)
+        }
 
         parallelBlockGroup = {
           blockName: parallelBlockName,
@@ -1379,6 +1384,7 @@ export const TagDropdown: React.FC<TagDropdownProps> = ({
           blockType: 'parallel',
           tags: contextualTags,
           distance: 0,
+          isContextual: true,
         }
       }
     }
@@ -1645,38 +1651,29 @@ export const TagDropdown: React.FC<TagDropdownProps> = ({
   const nestedBlockTagGroups: NestedBlockTagGroup[] = useMemo(() => {
     return filteredBlockTagGroups.map((group: BlockTagGroup) => {
       const normalizedBlockName = normalizeName(group.blockName)
-
-      // Handle loop/parallel contextual tags (index, currentItem, items)
       const directTags: NestedTag[] = []
       const tagsForTree: string[] = []
 
       group.tags.forEach((tag: string) => {
         const tagParts = tag.split('.')
 
-        // Loop/parallel contextual tags without block prefix
-        if (
-          (group.blockType === 'loop' || group.blockType === 'parallel') &&
-          tagParts.length === 1
-        ) {
+        if (tagParts.length === 1) {
           directTags.push({
             key: tag,
             display: tag,
             fullTag: tag,
           })
         } else if (tagParts.length === 2) {
-          // Direct property like blockname.property
           directTags.push({
             key: tagParts[1],
             display: tagParts[1],
             fullTag: tag,
           })
         } else {
-          // Nested property - add to tree builder
           tagsForTree.push(tag)
         }
       })
 
-      // Build recursive tree from nested tags
       const nestedTags = [...directTags, ...buildNestedTagTree(tagsForTree, normalizedBlockName)]
 
       return {
@@ -1800,13 +1797,19 @@ export const TagDropdown: React.FC<TagDropdownProps> = ({
           processedTag = tag
         }
       } else if (
-        blockGroup &&
+        blockGroup?.isContextual &&
         (blockGroup.blockType === 'loop' || blockGroup.blockType === 'parallel')
       ) {
-        if (!tag.includes('.') && ['index', 'currentItem', 'items'].includes(tag)) {
-          processedTag = `${blockGroup.blockType}.${tag}`
+        const tagParts = tag.split('.')
+        if (tagParts.length === 1) {
+          processedTag = blockGroup.blockType
         } else {
-          processedTag = tag
+          const lastPart = tagParts[tagParts.length - 1]
+          if (['index', 'currentItem', 'items'].includes(lastPart)) {
+            processedTag = `${blockGroup.blockType}.${lastPart}`
+          } else {
+            processedTag = tag
+          }
         }
       }
 

apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/tag-dropdown/types.ts

@@ -7,6 +7,8 @@ export interface BlockTagGroup {
   blockType: string
   tags: string[]
   distance: number
+  /** True if this is a contextual group (loop/parallel iteration context available inside the subflow) */
+  isContextual?: boolean
 }
 
 /**

apps/sim/blocks/blocks/gmail.ts

@@ -242,15 +242,9 @@ Return ONLY the email body - no explanations, no extra text.`,
       id: 'messageId',
       title: 'Message ID',
       type: 'short-input',
-      placeholder: 'Enter message ID to read (optional)',
-      condition: {
-        field: 'operation',
-        value: 'read_gmail',
-        and: {
-          field: 'folder',
-          value: '',
-        },
-      },
+      placeholder: 'Read specific email by ID (overrides label/folder)',
+      condition: { field: 'operation', value: 'read_gmail' },
+      mode: 'advanced',
     },
     // Search Fields
     {

apps/sim/blocks/blocks/router.ts

@@ -129,12 +129,9 @@ ROUTING RULES:
 3. If the context is even partially related to a route's description, select that route
 4. ONLY output NO_MATCH if the context is completely unrelated to ALL route descriptions
 
-OUTPUT FORMAT:
-- Output EXACTLY one route ID (copied exactly as shown above) OR "NO_MATCH"
-- No explanation, no punctuation, no additional text
-- Just the route ID or NO_MATCH
-
-Your response:`
+Respond with a JSON object containing:
+- route: EXACTLY one route ID (copied exactly as shown above) OR "NO_MATCH"
+- reasoning: A brief explanation (1-2 sentences) of why you chose this route`
 }
 
 /**
@@ -272,6 +269,7 @@ interface RouterV2Response extends ToolResponse {
       total: number
     }
     selectedRoute: string
+    reasoning: string
     selectedPath: {
       blockId: string
       blockType: string
@@ -355,6 +353,7 @@ export const RouterV2Block: BlockConfig<RouterV2Response> = {
     tokens: { type: 'json', description: 'Token usage' },
     cost: { type: 'json', description: 'Cost information' },
     selectedRoute: { type: 'string', description: 'Selected route ID' },
+    reasoning: { type: 'string', description: 'Explanation of why this route was chosen' },
     selectedPath: { type: 'json', description: 'Selected routing path' },
   },
 }

apps/sim/executor/constants.ts

@@ -120,6 +120,12 @@ export const SPECIAL_REFERENCE_PREFIXES = [
   REFERENCE.PREFIX.VARIABLE,
 ] as const
 
+export const RESERVED_BLOCK_NAMES = [
+  REFERENCE.PREFIX.LOOP,
+  REFERENCE.PREFIX.PARALLEL,
+  REFERENCE.PREFIX.VARIABLE,
+] as const
+
 export const LOOP_REFERENCE = {
   ITERATION: 'iteration',
   INDEX: 'index',

apps/sim/executor/dag/builder.test.ts

@@ -24,6 +24,71 @@ function createBlock(id: string, metadataId: string): SerializedBlock {
   }
 }
 
+describe('DAGBuilder disabled subflow validation', () => {
+  it('skips validation for disabled loops with no blocks inside', () => {
+    const workflow: SerializedWorkflow = {
+      version: '1',
+      blocks: [
+        createBlock('start', BlockType.STARTER),
+        { ...createBlock('loop-block', BlockType.FUNCTION), enabled: false },
+      ],
+      connections: [],
+      loops: {
+        'loop-1': {
+          id: 'loop-1',
+          nodes: [], // Empty loop - would normally throw
+          iterations: 3,
+        },
+      },
+    }
+
+    const builder = new DAGBuilder()
+    // Should not throw even though loop has no blocks inside
+    expect(() => builder.build(workflow)).not.toThrow()
+  })
+
+  it('skips validation for disabled parallels with no blocks inside', () => {
+    const workflow: SerializedWorkflow = {
+      version: '1',
+      blocks: [createBlock('start', BlockType.STARTER)],
+      connections: [],
+      loops: {},
+      parallels: {
+        'parallel-1': {
+          id: 'parallel-1',
+          nodes: [], // Empty parallel - would normally throw
+        },
+      },
+    }
+
+    const builder = new DAGBuilder()
+    // Should not throw even though parallel has no blocks inside
+    expect(() => builder.build(workflow)).not.toThrow()
+  })
+
+  it('skips validation for loops where all inner blocks are disabled', () => {
+    const workflow: SerializedWorkflow = {
+      version: '1',
+      blocks: [
+        createBlock('start', BlockType.STARTER),
+        { ...createBlock('inner-block', BlockType.FUNCTION), enabled: false },
+      ],
+      connections: [],
+      loops: {
+        'loop-1': {
+          id: 'loop-1',
+          nodes: ['inner-block'], // Has node but it's disabled
+          iterations: 3,
+        },
+      },
+    }
+
+    const builder = new DAGBuilder()
+    // Should not throw - loop is effectively disabled since all inner blocks are disabled
+    expect(() => builder.build(workflow)).not.toThrow()
+  })
+})
+
 describe('DAGBuilder human-in-the-loop transformation', () => {
   it('creates trigger nodes and rewires edges for pause blocks', () => {
     const workflow: SerializedWorkflow = {

apps/sim/executor/dag/builder.ts

@@ -136,17 +136,18 @@ export class DAGBuilder {
     nodes: string[] | undefined,
     type: 'Loop' | 'Parallel'
   ): void {
+    const sentinelStartId =
+      type === 'Loop' ? buildSentinelStartId(id) : buildParallelSentinelStartId(id)
+    const sentinelStartNode = dag.nodes.get(sentinelStartId)
+
+    if (!sentinelStartNode) return
+
     if (!nodes || nodes.length === 0) {
       throw new Error(
         `${type} has no blocks inside. Add at least one block to the ${type.toLowerCase()}.`
       )
     }
 
-    const sentinelStartId =
-      type === 'Loop' ? buildSentinelStartId(id) : buildParallelSentinelStartId(id)
-    const sentinelStartNode = dag.nodes.get(sentinelStartId)
-    if (!sentinelStartNode) return
-
     const hasConnections = Array.from(sentinelStartNode.outgoingEdges.values()).some((edge) =>
       nodes.includes(extractBaseBlockId(edge.target))
     )

apps/sim/executor/execution/edge-manager.ts

@@ -20,21 +20,13 @@ export class EdgeManager {
     const activatedTargets: string[] = []
     const edgesToDeactivate: Array<{ target: string; handle?: string }> = []
 
-    // First pass: categorize edges as activating or deactivating
-    // Don't modify incomingEdges yet - we need the original state for deactivation checks
-    for (const [edgeId, edge] of node.outgoingEdges) {
+    for (const [, edge] of node.outgoingEdges) {
       if (skipBackwardsEdge && this.isBackwardsEdge(edge.sourceHandle)) {
         continue
       }
 
-      const shouldActivate = this.shouldActivateEdge(edge, output)
-      if (!shouldActivate) {
-        const isLoopEdge =
-          edge.sourceHandle === EDGE.LOOP_CONTINUE ||
-          edge.sourceHandle === EDGE.LOOP_CONTINUE_ALT ||
-          edge.sourceHandle === EDGE.LOOP_EXIT
-
-        if (!isLoopEdge) {
+      if (!this.shouldActivateEdge(edge, output)) {
+        if (!this.isLoopEdge(edge.sourceHandle)) {
           edgesToDeactivate.push({ target: edge.target, handle: edge.sourceHandle })
         }
         continue
@@ -43,13 +35,19 @@ export class EdgeManager {
       activatedTargets.push(edge.target)
     }
 
-    // Second pass: process deactivations while incomingEdges is still intact
-    // This ensures hasActiveIncomingEdges can find all potential sources
+    const cascadeTargets = new Set<string>()
     for (const { target, handle } of edgesToDeactivate) {
-      this.deactivateEdgeAndDescendants(node.id, target, handle)
+      this.deactivateEdgeAndDescendants(node.id, target, handle, cascadeTargets)
+    }
+
+    if (activatedTargets.length === 0) {
+      for (const { target } of edgesToDeactivate) {
+        if (this.isTerminalControlNode(target)) {
+          cascadeTargets.add(target)
+        }
+      }
     }
 
-    // Third pass: update incomingEdges for activated targets
     for (const targetId of activatedTargets) {
       const targetNode = this.dag.nodes.get(targetId)
       if (!targetNode) {
@@ -59,28 +57,25 @@ export class EdgeManager {
       targetNode.incomingEdges.delete(node.id)
     }
 
-    // Fourth pass: check readiness after all edge processing is complete
     for (const targetId of activatedTargets) {
-      const targetNode = this.dag.nodes.get(targetId)
-      if (targetNode && this.isNodeReady(targetNode)) {
+      if (this.isTargetReady(targetId)) {
         readyNodes.push(targetId)
       }
     }
 
+    for (const targetId of cascadeTargets) {
+      if (!readyNodes.includes(targetId) && !activatedTargets.includes(targetId)) {
+        if (this.isTargetReady(targetId)) {
+          readyNodes.push(targetId)
+        }
+      }
+    }
+
     return readyNodes
   }
 
   isNodeReady(node: DAGNode): boolean {
-    if (node.incomingEdges.size === 0) {
-      return true
-    }
-
-    const activeIncomingCount = this.countActiveIncomingEdges(node)
-    if (activeIncomingCount > 0) {
-      return false
-    }
-
-    return true
+    return node.incomingEdges.size === 0 || this.countActiveIncomingEdges(node) === 0
   }
 
   restoreIncomingEdge(targetNodeId: string, sourceNodeId: string): void {
@@ -99,13 +94,10 @@ export class EdgeManager {
 
   /**
    * Clear deactivated edges for a set of nodes (used when restoring loop state for next iteration).
-   * This ensures error/success edges can be re-evaluated on each iteration.
    */
   clearDeactivatedEdgesForNodes(nodeIds: Set<string>): void {
     const edgesToRemove: string[] = []
     for (const edgeKey of this.deactivatedEdges) {
-      // Edge key format is "sourceId-targetId-handle"
-      // Check if either source or target is in the nodeIds set
       for (const nodeId of nodeIds) {
         if (edgeKey.startsWith(`${nodeId}-`) || edgeKey.includes(`-${nodeId}-`)) {
           edgesToRemove.push(edgeKey)
@@ -118,6 +110,44 @@ export class EdgeManager {
     }
   }
 
+  private isTargetReady(targetId: string): boolean {
+    const targetNode = this.dag.nodes.get(targetId)
+    return targetNode ? this.isNodeReady(targetNode) : false
+  }
+
+  private isLoopEdge(handle?: string): boolean {
+    return (
+      handle === EDGE.LOOP_CONTINUE ||
+      handle === EDGE.LOOP_CONTINUE_ALT ||
+      handle === EDGE.LOOP_EXIT
+    )
+  }
+
+  private isControlEdge(handle?: string): boolean {
+    return (
+      handle === EDGE.LOOP_CONTINUE ||
+      handle === EDGE.LOOP_CONTINUE_ALT ||
+      handle === EDGE.LOOP_EXIT ||
+      handle === EDGE.PARALLEL_EXIT
+    )
+  }
+
+  private isBackwardsEdge(sourceHandle?: string): boolean {
+    return sourceHandle === EDGE.LOOP_CONTINUE || sourceHandle === EDGE.LOOP_CONTINUE_ALT
+  }
+
+  private isTerminalControlNode(nodeId: string): boolean {
+    const node = this.dag.nodes.get(nodeId)
+    if (!node || node.outgoingEdges.size === 0) return false
+
+    for (const [, edge] of node.outgoingEdges) {
+      if (!this.isControlEdge(edge.sourceHandle)) {
+        return false
+      }
+    }
+    return true
+  }
+
   private shouldActivateEdge(edge: DAGEdge, output: NormalizedBlockOutput): boolean {
     const handle = edge.sourceHandle
 
@@ -159,14 +189,12 @@ export class EdgeManager {
     }
   }
 
-  private isBackwardsEdge(sourceHandle?: string): boolean {
-    return sourceHandle === EDGE.LOOP_CONTINUE || sourceHandle === EDGE.LOOP_CONTINUE_ALT
-  }
-
   private deactivateEdgeAndDescendants(
     sourceId: string,
     targetId: string,
-    sourceHandle?: string
+    sourceHandle?: string,
+    cascadeTargets?: Set<string>,
+    isCascade = false
   ): void {
     const edgeKey = this.createEdgeKey(sourceId, targetId, sourceHandle)
     if (this.deactivatedEdges.has(edgeKey)) {
@@ -174,38 +202,46 @@ export class EdgeManager {
     }
 
     this.deactivatedEdges.add(edgeKey)
+
     const targetNode = this.dag.nodes.get(targetId)
     if (!targetNode) return
 
-    // Check if target has other active incoming edges
-    // Pass the specific edge key being deactivated, not just source ID,
-    // to handle multiple edges from same source to same target (e.g., condition branches)
-    const hasOtherActiveIncoming = this.hasActiveIncomingEdges(targetNode, edgeKey)
-    if (!hasOtherActiveIncoming) {
-      for (const [_, outgoingEdge] of targetNode.outgoingEdges) {
-        this.deactivateEdgeAndDescendants(targetId, outgoingEdge.target, outgoingEdge.sourceHandle)
+    if (isCascade && this.isTerminalControlNode(targetId)) {
+      cascadeTargets?.add(targetId)
+    }
+
+    if (this.hasActiveIncomingEdges(targetNode, edgeKey)) {
+      return
+    }
+
+    for (const [, outgoingEdge] of targetNode.outgoingEdges) {
+      if (!this.isControlEdge(outgoingEdge.sourceHandle)) {
+        this.deactivateEdgeAndDescendants(
+          targetId,
+          outgoingEdge.target,
+          outgoingEdge.sourceHandle,
+          cascadeTargets,
+          true
+        )
       }
     }
   }
 
   /**
    * Checks if a node has any active incoming edges besides the one being excluded.
-   * This properly handles the case where multiple edges from the same source go to
-   * the same target (e.g., multiple condition branches pointing to one block).
    */
   private hasActiveIncomingEdges(node: DAGNode, excludeEdgeKey: string): boolean {
     for (const incomingSourceId of node.incomingEdges) {
       const incomingNode = this.dag.nodes.get(incomingSourceId)
       if (!incomingNode) continue
 
-      for (const [_, incomingEdge] of incomingNode.outgoingEdges) {
+      for (const [, incomingEdge] of incomingNode.outgoingEdges) {
         if (incomingEdge.target === node.id) {
           const incomingEdgeKey = this.createEdgeKey(
             incomingSourceId,
             node.id,
             incomingEdge.sourceHandle
           )
-          // Skip the specific edge being excluded, but check other edges from same source
           if (incomingEdgeKey === excludeEdgeKey) continue
           if (!this.deactivatedEdges.has(incomingEdgeKey)) {
             return true

apps/sim/executor/execution/engine.test.ts

@@ -554,6 +554,413 @@ describe('ExecutionEngine', () => {
     })
   })
 
+  describe('Error handling in execution', () => {
+    it('should fail execution when a single node throws an error', async () => {
+      const startNode = createMockNode('start', 'starter')
+      const errorNode = createMockNode('error-node', 'function')
+      startNode.outgoingEdges.set('edge1', { target: 'error-node' })
+
+      const dag = createMockDAG([startNode, errorNode])
+      const context = createMockContext()
+      const edgeManager = createMockEdgeManager((node) => {
+        if (node.id === 'start') return ['error-node']
+        return []
+      })
+
+      const nodeOrchestrator = {
+        executionCount: 0,
+        executeNode: vi.fn().mockImplementation(async (_ctx: ExecutionContext, nodeId: string) => {
+          if (nodeId === 'error-node') {
+            throw new Error('Block execution failed')
+          }
+          return { nodeId, output: {}, isFinalOutput: false }
+        }),
+        handleNodeCompletion: vi.fn(),
+      } as unknown as MockNodeOrchestrator
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+
+      await expect(engine.run('start')).rejects.toThrow('Block execution failed')
+    })
+
+    it('should stop parallel branches when one branch throws an error', async () => {
+      const startNode = createMockNode('start', 'starter')
+      const parallelNodes = Array.from({ length: 5 }, (_, i) =>
+        createMockNode(`parallel${i}`, 'function')
+      )
+
+      parallelNodes.forEach((_, i) => {
+        startNode.outgoingEdges.set(`edge${i}`, { target: `parallel${i}` })
+      })
+
+      const dag = createMockDAG([startNode, ...parallelNodes])
+      const context = createMockContext()
+      const edgeManager = createMockEdgeManager((node) => {
+        if (node.id === 'start') return parallelNodes.map((_, i) => `parallel${i}`)
+        return []
+      })
+
+      const executedNodes: string[] = []
+      const nodeOrchestrator = {
+        executionCount: 0,
+        executeNode: vi.fn().mockImplementation(async (_ctx: ExecutionContext, nodeId: string) => {
+          executedNodes.push(nodeId)
+          if (nodeId === 'parallel0') {
+            await new Promise((resolve) => setTimeout(resolve, 10))
+            throw new Error('Parallel branch failed')
+          }
+          await new Promise((resolve) => setTimeout(resolve, 100))
+          return { nodeId, output: {}, isFinalOutput: false }
+        }),
+        handleNodeCompletion: vi.fn(),
+      } as unknown as MockNodeOrchestrator
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+
+      await expect(engine.run('start')).rejects.toThrow('Parallel branch failed')
+    })
+
+    it('should capture only the first error when multiple parallel branches fail', async () => {
+      const startNode = createMockNode('start', 'starter')
+      const parallelNodes = Array.from({ length: 3 }, (_, i) =>
+        createMockNode(`parallel${i}`, 'function')
+      )
+
+      parallelNodes.forEach((_, i) => {
+        startNode.outgoingEdges.set(`edge${i}`, { target: `parallel${i}` })
+      })
+
+      const dag = createMockDAG([startNode, ...parallelNodes])
+      const context = createMockContext()
+      const edgeManager = createMockEdgeManager((node) => {
+        if (node.id === 'start') return parallelNodes.map((_, i) => `parallel${i}`)
+        return []
+      })
+
+      const nodeOrchestrator = {
+        executionCount: 0,
+        executeNode: vi.fn().mockImplementation(async (_ctx: ExecutionContext, nodeId: string) => {
+          if (nodeId === 'parallel0') {
+            await new Promise((resolve) => setTimeout(resolve, 10))
+            throw new Error('First error')
+          }
+          if (nodeId === 'parallel1') {
+            await new Promise((resolve) => setTimeout(resolve, 20))
+            throw new Error('Second error')
+          }
+          if (nodeId === 'parallel2') {
+            await new Promise((resolve) => setTimeout(resolve, 30))
+            throw new Error('Third error')
+          }
+          return { nodeId, output: {}, isFinalOutput: false }
+        }),
+        handleNodeCompletion: vi.fn(),
+      } as unknown as MockNodeOrchestrator
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+
+      await expect(engine.run('start')).rejects.toThrow('First error')
+    })
+
+    it('should wait for ongoing executions to complete before throwing error', async () => {
+      const startNode = createMockNode('start', 'starter')
+      const fastErrorNode = createMockNode('fast-error', 'function')
+      const slowNode = createMockNode('slow', 'function')
+
+      startNode.outgoingEdges.set('edge1', { target: 'fast-error' })
+      startNode.outgoingEdges.set('edge2', { target: 'slow' })
+
+      const dag = createMockDAG([startNode, fastErrorNode, slowNode])
+      const context = createMockContext()
+      const edgeManager = createMockEdgeManager((node) => {
+        if (node.id === 'start') return ['fast-error', 'slow']
+        return []
+      })
+
+      let slowNodeCompleted = false
+      const nodeOrchestrator = {
+        executionCount: 0,
+        executeNode: vi.fn().mockImplementation(async (_ctx: ExecutionContext, nodeId: string) => {
+          if (nodeId === 'fast-error') {
+            await new Promise((resolve) => setTimeout(resolve, 10))
+            throw new Error('Fast error')
+          }
+          if (nodeId === 'slow') {
+            await new Promise((resolve) => setTimeout(resolve, 50))
+            slowNodeCompleted = true
+            return { nodeId, output: {}, isFinalOutput: false }
+          }
+          return { nodeId, output: {}, isFinalOutput: false }
+        }),
+        handleNodeCompletion: vi.fn(),
+      } as unknown as MockNodeOrchestrator
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+
+      await expect(engine.run('start')).rejects.toThrow('Fast error')
+
+      expect(slowNodeCompleted).toBe(true)
+    })
+
+    it('should not queue new nodes after an error occurs', async () => {
+      const startNode = createMockNode('start', 'starter')
+      const errorNode = createMockNode('error-node', 'function')
+      const afterErrorNode = createMockNode('after-error', 'function')
+
+      startNode.outgoingEdges.set('edge1', { target: 'error-node' })
+      errorNode.outgoingEdges.set('edge2', { target: 'after-error' })
+
+      const dag = createMockDAG([startNode, errorNode, afterErrorNode])
+      const context = createMockContext()
+
+      const queuedNodes: string[] = []
+      const edgeManager = createMockEdgeManager((node) => {
+        if (node.id === 'start') {
+          queuedNodes.push('error-node')
+          return ['error-node']
+        }
+        if (node.id === 'error-node') {
+          queuedNodes.push('after-error')
+          return ['after-error']
+        }
+        return []
+      })
+
+      const executedNodes: string[] = []
+      const nodeOrchestrator = {
+        executionCount: 0,
+        executeNode: vi.fn().mockImplementation(async (_ctx: ExecutionContext, nodeId: string) => {
+          executedNodes.push(nodeId)
+          if (nodeId === 'error-node') {
+            throw new Error('Node error')
+          }
+          return { nodeId, output: {}, isFinalOutput: false }
+        }),
+        handleNodeCompletion: vi.fn(),
+      } as unknown as MockNodeOrchestrator
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+
+      await expect(engine.run('start')).rejects.toThrow('Node error')
+
+      expect(executedNodes).not.toContain('after-error')
+    })
+
+    it('should populate error result with metadata when execution fails', async () => {
+      const startNode = createMockNode('start', 'starter')
+      const errorNode = createMockNode('error-node', 'function')
+      startNode.outgoingEdges.set('edge1', { target: 'error-node' })
+
+      const dag = createMockDAG([startNode, errorNode])
+      const context = createMockContext()
+      context.blockLogs.push({
+        blockId: 'start',
+        blockName: 'Start',
+        blockType: 'starter',
+        startedAt: new Date().toISOString(),
+        endedAt: new Date().toISOString(),
+        durationMs: 10,
+        success: true,
+      })
+
+      const edgeManager = createMockEdgeManager((node) => {
+        if (node.id === 'start') return ['error-node']
+        return []
+      })
+
+      const nodeOrchestrator = {
+        executionCount: 0,
+        executeNode: vi.fn().mockImplementation(async (_ctx: ExecutionContext, nodeId: string) => {
+          if (nodeId === 'error-node') {
+            const error = new Error('Execution failed') as any
+            error.executionResult = {
+              success: false,
+              output: { partial: 'data' },
+              logs: context.blockLogs,
+              metadata: context.metadata,
+            }
+            throw error
+          }
+          return { nodeId, output: {}, isFinalOutput: false }
+        }),
+        handleNodeCompletion: vi.fn(),
+      } as unknown as MockNodeOrchestrator
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+
+      try {
+        await engine.run('start')
+        expect.fail('Should have thrown')
+      } catch (error: any) {
+        expect(error.executionResult).toBeDefined()
+        expect(error.executionResult.metadata.endTime).toBeDefined()
+        expect(error.executionResult.metadata.duration).toBeDefined()
+      }
+    })
+
+    it('should prefer cancellation status over error when both occur', async () => {
+      const abortController = new AbortController()
+
+      const startNode = createMockNode('start', 'starter')
+      const errorNode = createMockNode('error-node', 'function')
+      startNode.outgoingEdges.set('edge1', { target: 'error-node' })
+
+      const dag = createMockDAG([startNode, errorNode])
+      const context = createMockContext({ abortSignal: abortController.signal })
+      const edgeManager = createMockEdgeManager((node) => {
+        if (node.id === 'start') return ['error-node']
+        return []
+      })
+
+      const nodeOrchestrator = {
+        executionCount: 0,
+        executeNode: vi.fn().mockImplementation(async (_ctx: ExecutionContext, nodeId: string) => {
+          if (nodeId === 'error-node') {
+            abortController.abort()
+            throw new Error('Node error')
+          }
+          return { nodeId, output: {}, isFinalOutput: false }
+        }),
+        handleNodeCompletion: vi.fn(),
+      } as unknown as MockNodeOrchestrator
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+      const result = await engine.run('start')
+
+      expect(result.status).toBe('cancelled')
+      expect(result.success).toBe(false)
+    })
+
+    it('should stop loop iteration when error occurs in loop body', async () => {
+      const loopStartNode = createMockNode('loop-start', 'loop_sentinel')
+      loopStartNode.metadata = { isSentinel: true, sentinelType: 'start', loopId: 'loop1' }
+
+      const loopBodyNode = createMockNode('loop-body', 'function')
+      loopBodyNode.metadata = { isLoopNode: true, loopId: 'loop1' }
+
+      const loopEndNode = createMockNode('loop-end', 'loop_sentinel')
+      loopEndNode.metadata = { isSentinel: true, sentinelType: 'end', loopId: 'loop1' }
+
+      const afterLoopNode = createMockNode('after-loop', 'function')
+
+      loopStartNode.outgoingEdges.set('edge1', { target: 'loop-body' })
+      loopBodyNode.outgoingEdges.set('edge2', { target: 'loop-end' })
+      loopEndNode.outgoingEdges.set('loop_continue', {
+        target: 'loop-start',
+        sourceHandle: 'loop_continue',
+      })
+      loopEndNode.outgoingEdges.set('loop_complete', {
+        target: 'after-loop',
+        sourceHandle: 'loop_complete',
+      })
+
+      const dag = createMockDAG([loopStartNode, loopBodyNode, loopEndNode, afterLoopNode])
+      const context = createMockContext()
+
+      let iterationCount = 0
+      const edgeManager = createMockEdgeManager((node) => {
+        if (node.id === 'loop-start') return ['loop-body']
+        if (node.id === 'loop-body') return ['loop-end']
+        if (node.id === 'loop-end') {
+          iterationCount++
+          if (iterationCount < 5) return ['loop-start']
+          return ['after-loop']
+        }
+        return []
+      })
+
+      const nodeOrchestrator = {
+        executionCount: 0,
+        executeNode: vi.fn().mockImplementation(async (_ctx: ExecutionContext, nodeId: string) => {
+          if (nodeId === 'loop-body' && iterationCount >= 2) {
+            throw new Error('Loop body error on iteration 3')
+          }
+          return { nodeId, output: {}, isFinalOutput: false }
+        }),
+        handleNodeCompletion: vi.fn(),
+      } as unknown as MockNodeOrchestrator
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+
+      await expect(engine.run('loop-start')).rejects.toThrow('Loop body error on iteration 3')
+
+      expect(iterationCount).toBeLessThanOrEqual(3)
+    })
+
+    it('should handle error that is not an Error instance', async () => {
+      const startNode = createMockNode('start', 'starter')
+      const errorNode = createMockNode('error-node', 'function')
+      startNode.outgoingEdges.set('edge1', { target: 'error-node' })
+
+      const dag = createMockDAG([startNode, errorNode])
+      const context = createMockContext()
+      const edgeManager = createMockEdgeManager((node) => {
+        if (node.id === 'start') return ['error-node']
+        return []
+      })
+
+      const nodeOrchestrator = {
+        executionCount: 0,
+        executeNode: vi.fn().mockImplementation(async (_ctx: ExecutionContext, nodeId: string) => {
+          if (nodeId === 'error-node') {
+            throw 'String error message'
+          }
+          return { nodeId, output: {}, isFinalOutput: false }
+        }),
+        handleNodeCompletion: vi.fn(),
+      } as unknown as MockNodeOrchestrator
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+
+      await expect(engine.run('start')).rejects.toThrow('String error message')
+    })
+
+    it('should preserve partial output when error occurs after some blocks complete', async () => {
+      const startNode = createMockNode('start', 'starter')
+      const successNode = createMockNode('success', 'function')
+      const errorNode = createMockNode('error-node', 'function')
+
+      startNode.outgoingEdges.set('edge1', { target: 'success' })
+      successNode.outgoingEdges.set('edge2', { target: 'error-node' })
+
+      const dag = createMockDAG([startNode, successNode, errorNode])
+      const context = createMockContext()
+      const edgeManager = createMockEdgeManager((node) => {
+        if (node.id === 'start') return ['success']
+        if (node.id === 'success') return ['error-node']
+        return []
+      })
+
+      const nodeOrchestrator = {
+        executionCount: 0,
+        executeNode: vi.fn().mockImplementation(async (_ctx: ExecutionContext, nodeId: string) => {
+          if (nodeId === 'success') {
+            return { nodeId, output: { successData: 'preserved' }, isFinalOutput: false }
+          }
+          if (nodeId === 'error-node') {
+            throw new Error('Late error')
+          }
+          return { nodeId, output: {}, isFinalOutput: false }
+        }),
+        handleNodeCompletion: vi.fn(),
+      } as unknown as MockNodeOrchestrator
+
+      const engine = new ExecutionEngine(context, dag, edgeManager, nodeOrchestrator)
+
+      try {
+        await engine.run('start')
+        expect.fail('Should have thrown')
+      } catch (error: any) {
+        // Verify the error was thrown
+        expect(error.message).toBe('Late error')
+        // The partial output should be available in executionResult if attached
+        if (error.executionResult) {
+          expect(error.executionResult.output).toBeDefined()
+        }
+      }
+    })
+  })
+
   describe('Cancellation flag behavior', () => {
     it('should set cancelledFlag when abort signal fires', async () => {
       const abortController = new AbortController()

apps/sim/executor/execution/engine.ts

@@ -25,6 +25,8 @@ export class ExecutionEngine {
   private pausedBlocks: Map<string, PauseMetadata> = new Map()
   private allowResumeTriggers: boolean
   private cancelledFlag = false
+  private errorFlag = false
+  private executionError: Error | null = null
   private lastCancellationCheck = 0
   private readonly useRedisCancellation: boolean
   private readonly CANCELLATION_CHECK_INTERVAL_MS = 500
@@ -103,7 +105,7 @@ export class ExecutionEngine {
       this.initializeQueue(triggerBlockId)
 
       while (this.hasWork()) {
-        if (await this.checkCancellation()) {
+        if ((await this.checkCancellation()) || this.errorFlag) {
           break
         }
         await this.processQueue()
@@ -113,6 +115,11 @@ export class ExecutionEngine {
         await this.waitForAllExecutions()
       }
 
+      // Rethrow the captured error so it's handled by the catch block
+      if (this.errorFlag && this.executionError) {
+        throw this.executionError
+      }
+
       if (this.pausedBlocks.size > 0) {
         return this.buildPausedResult(startTime)
       }
@@ -196,11 +203,17 @@ export class ExecutionEngine {
   }
 
   private trackExecution(promise: Promise<void>): void {
-    this.executing.add(promise)
-    promise.catch(() => {})
-    promise.finally(() => {
-      this.executing.delete(promise)
-    })
+    const trackedPromise = promise
+      .catch((error) => {
+        if (!this.errorFlag) {
+          this.errorFlag = true
+          this.executionError = error instanceof Error ? error : new Error(String(error))
+        }
+      })
+      .finally(() => {
+        this.executing.delete(trackedPromise)
+      })
+    this.executing.add(trackedPromise)
   }
 
   private async waitForAnyExecution(): Promise<void> {
@@ -315,7 +328,7 @@ export class ExecutionEngine {
 
   private async processQueue(): Promise<void> {
     while (this.readyQueue.length > 0) {
-      if (await this.checkCancellation()) {
+      if ((await this.checkCancellation()) || this.errorFlag) {
         break
       }
       const nodeId = this.dequeue()
@@ -324,7 +337,7 @@ export class ExecutionEngine {
       this.trackExecution(promise)
     }
 
-    if (this.executing.size > 0 && !this.cancelledFlag) {
+    if (this.executing.size > 0 && !this.cancelledFlag && !this.errorFlag) {
       await this.waitForAnyExecution()
     }
   }

apps/sim/executor/handlers/agent/agent-handler.ts

@@ -305,7 +305,7 @@ export class AgentBlockHandler implements BlockHandler {
       base.executeFunction = async (callParams: Record<string, any>) => {
         const mergedParams = mergeToolParameters(userProvidedParams, callParams)
 
-        const { blockData, blockNameMapping } = collectBlockData(ctx)
+        const { blockData, blockNameMapping, blockOutputSchemas } = collectBlockData(ctx)
 
         const result = await executeTool(
           'function_execute',
@@ -317,6 +317,7 @@ export class AgentBlockHandler implements BlockHandler {
             workflowVariables: ctx.workflowVariables || {},
             blockData,
             blockNameMapping,
+            blockOutputSchemas,
             isCustomTool: true,
             _context: {
               workflowId: ctx.workflowId,

apps/sim/executor/handlers/condition/condition-handler.ts

@@ -26,7 +26,7 @@ export async function evaluateConditionExpression(
     const contextSetup = `const context = ${JSON.stringify(evalContext)};`
     const code = `${contextSetup}\nreturn Boolean(${conditionExpression})`
 
-    const { blockData, blockNameMapping } = collectBlockData(ctx)
+    const { blockData, blockNameMapping, blockOutputSchemas } = collectBlockData(ctx)
 
     const result = await executeTool(
       'function_execute',
@@ -37,6 +37,7 @@ export async function evaluateConditionExpression(
         workflowVariables: ctx.workflowVariables || {},
         blockData,
         blockNameMapping,
+        blockOutputSchemas,
         _context: {
           workflowId: ctx.workflowId,
           workspaceId: ctx.workspaceId,

apps/sim/executor/handlers/function/function-handler.test.ts

@@ -75,7 +75,12 @@ describe('FunctionBlockHandler', () => {
       workflowVariables: {},
       blockData: {},
       blockNameMapping: {},
-      _context: { workflowId: mockContext.workflowId, workspaceId: mockContext.workspaceId },
+      blockOutputSchemas: {},
+      _context: {
+        workflowId: mockContext.workflowId,
+        workspaceId: mockContext.workspaceId,
+        isDeployedContext: mockContext.isDeployedContext,
+      },
     }
     const expectedOutput: any = { result: 'Success' }
 
@@ -84,8 +89,8 @@ describe('FunctionBlockHandler', () => {
     expect(mockExecuteTool).toHaveBeenCalledWith(
       'function_execute',
       expectedToolParams,
-      false, // skipPostProcess
-      mockContext // execution context
+      false,
+      mockContext
     )
     expect(result).toEqual(expectedOutput)
   })
@@ -107,7 +112,12 @@ describe('FunctionBlockHandler', () => {
       workflowVariables: {},
       blockData: {},
       blockNameMapping: {},
-      _context: { workflowId: mockContext.workflowId, workspaceId: mockContext.workspaceId },
+      blockOutputSchemas: {},
+      _context: {
+        workflowId: mockContext.workflowId,
+        workspaceId: mockContext.workspaceId,
+        isDeployedContext: mockContext.isDeployedContext,
+      },
     }
     const expectedOutput: any = { result: 'Success' }
 
@@ -116,8 +126,8 @@ describe('FunctionBlockHandler', () => {
     expect(mockExecuteTool).toHaveBeenCalledWith(
       'function_execute',
       expectedToolParams,
-      false, // skipPostProcess
-      mockContext // execution context
+      false,
+      mockContext
     )
     expect(result).toEqual(expectedOutput)
   })
@@ -132,7 +142,12 @@ describe('FunctionBlockHandler', () => {
       workflowVariables: {},
       blockData: {},
       blockNameMapping: {},
-      _context: { workflowId: mockContext.workflowId, workspaceId: mockContext.workspaceId },
+      blockOutputSchemas: {},
+      _context: {
+        workflowId: mockContext.workflowId,
+        workspaceId: mockContext.workspaceId,
+        isDeployedContext: mockContext.isDeployedContext,
+      },
     }
 
     await handler.execute(mockContext, mockBlock, inputs)

apps/sim/executor/handlers/function/function-handler.ts

@@ -23,7 +23,7 @@ export class FunctionBlockHandler implements BlockHandler {
       ? inputs.code.map((c: { content: string }) => c.content).join('\n')
       : inputs.code
 
-    const { blockData, blockNameMapping } = collectBlockData(ctx)
+    const { blockData, blockNameMapping, blockOutputSchemas } = collectBlockData(ctx)
 
     const result = await executeTool(
       'function_execute',
@@ -35,6 +35,7 @@ export class FunctionBlockHandler implements BlockHandler {
         workflowVariables: ctx.workflowVariables || {},
         blockData,
         blockNameMapping,
+        blockOutputSchemas,
         _context: {
           workflowId: ctx.workflowId,
           workspaceId: ctx.workspaceId,

apps/sim/executor/handlers/router/router-handler.test.ts

@@ -1,7 +1,7 @@
 import '@sim/testing/mocks/executor'
 
 import { beforeEach, describe, expect, it, type Mock, vi } from 'vitest'
-import { generateRouterPrompt } from '@/blocks/blocks/router'
+import { generateRouterPrompt, generateRouterV2Prompt } from '@/blocks/blocks/router'
 import { BlockType } from '@/executor/constants'
 import { RouterBlockHandler } from '@/executor/handlers/router/router-handler'
 import type { ExecutionContext } from '@/executor/types'
@@ -9,6 +9,7 @@ import { getProviderFromModel } from '@/providers/utils'
 import type { SerializedBlock, SerializedWorkflow } from '@/serializer/types'
 
 const mockGenerateRouterPrompt = generateRouterPrompt as Mock
+const mockGenerateRouterV2Prompt = generateRouterV2Prompt as Mock
 const mockGetProviderFromModel = getProviderFromModel as Mock
 const mockFetch = global.fetch as unknown as Mock
 
@@ -44,7 +45,7 @@ describe('RouterBlockHandler', () => {
       metadata: { id: BlockType.ROUTER, name: 'Test Router' },
       position: { x: 50, y: 50 },
       config: { tool: BlockType.ROUTER, params: {} },
-      inputs: { prompt: 'string', model: 'string' }, // Using ParamType strings
+      inputs: { prompt: 'string', model: 'string' },
       outputs: {},
       enabled: true,
     }
@@ -72,14 +73,11 @@ describe('RouterBlockHandler', () => {
       workflow: mockWorkflow as SerializedWorkflow,
     }
 
-    // Reset mocks using vi
     vi.clearAllMocks()
 
-    // Default mock implementations
     mockGetProviderFromModel.mockReturnValue('openai')
     mockGenerateRouterPrompt.mockReturnValue('Generated System Prompt')
 
-    // Set up fetch mock to return a successful response
     mockFetch.mockImplementation(() => {
       return Promise.resolve({
         ok: true,
@@ -147,7 +145,6 @@ describe('RouterBlockHandler', () => {
       })
     )
 
-    // Verify the request body contains the expected data
     const fetchCallArgs = mockFetch.mock.calls[0]
     const requestBody = JSON.parse(fetchCallArgs[1].body)
     expect(requestBody).toMatchObject({
@@ -180,7 +177,6 @@ describe('RouterBlockHandler', () => {
     const inputs = { prompt: 'Test' }
     mockContext.workflow!.blocks = [mockBlock, mockTargetBlock2]
 
-    // Expect execute to throw because getTargetBlocks (called internally) will throw
     await expect(handler.execute(mockContext, mockBlock, inputs)).rejects.toThrow(
       'Target block target-block-1 not found'
     )
@@ -190,7 +186,6 @@ describe('RouterBlockHandler', () => {
   it('should throw error if LLM response is not a valid target block ID', async () => {
     const inputs = { prompt: 'Test', apiKey: 'test-api-key' }
 
-    // Override fetch mock to return an invalid block ID
     mockFetch.mockImplementationOnce(() => {
       return Promise.resolve({
         ok: true,
@@ -228,7 +223,6 @@ describe('RouterBlockHandler', () => {
   it('should handle server error responses', async () => {
     const inputs = { prompt: 'Test error handling.', apiKey: 'test-api-key' }
 
-    // Override fetch mock to return an error
     mockFetch.mockImplementationOnce(() => {
       return Promise.resolve({
         ok: false,
@@ -276,13 +270,12 @@ describe('RouterBlockHandler', () => {
 
     mockGetProviderFromModel.mockReturnValue('vertex')
 
-    // Mock the database query for Vertex credential
     const mockDb = await import('@sim/db')
     const mockAccount = {
       id: 'test-vertex-credential-id',
       accessToken: 'mock-access-token',
       refreshToken: 'mock-refresh-token',
-      expiresAt: new Date(Date.now() + 3600000), // 1 hour from now
+      expiresAt: new Date(Date.now() + 3600000),
     }
     vi.spyOn(mockDb.db.query.account, 'findFirst').mockResolvedValue(mockAccount as any)
 
@@ -300,3 +293,287 @@ describe('RouterBlockHandler', () => {
     expect(requestBody.apiKey).toBe('mock-access-token')
   })
 })
+
+describe('RouterBlockHandler V2', () => {
+  let handler: RouterBlockHandler
+  let mockRouterV2Block: SerializedBlock
+  let mockContext: ExecutionContext
+  let mockWorkflow: Partial<SerializedWorkflow>
+  let mockTargetBlock1: SerializedBlock
+  let mockTargetBlock2: SerializedBlock
+
+  beforeEach(() => {
+    mockTargetBlock1 = {
+      id: 'target-block-1',
+      metadata: { id: 'agent', name: 'Support Agent' },
+      position: { x: 100, y: 100 },
+      config: { tool: 'agent', params: {} },
+      inputs: {},
+      outputs: {},
+      enabled: true,
+    }
+    mockTargetBlock2 = {
+      id: 'target-block-2',
+      metadata: { id: 'agent', name: 'Sales Agent' },
+      position: { x: 100, y: 150 },
+      config: { tool: 'agent', params: {} },
+      inputs: {},
+      outputs: {},
+      enabled: true,
+    }
+    mockRouterV2Block = {
+      id: 'router-v2-block-1',
+      metadata: { id: BlockType.ROUTER_V2, name: 'Test Router V2' },
+      position: { x: 50, y: 50 },
+      config: { tool: BlockType.ROUTER_V2, params: {} },
+      inputs: {},
+      outputs: {},
+      enabled: true,
+    }
+    mockWorkflow = {
+      blocks: [mockRouterV2Block, mockTargetBlock1, mockTargetBlock2],
+      connections: [
+        {
+          source: mockRouterV2Block.id,
+          target: mockTargetBlock1.id,
+          sourceHandle: 'router-route-support',
+        },
+        {
+          source: mockRouterV2Block.id,
+          target: mockTargetBlock2.id,
+          sourceHandle: 'router-route-sales',
+        },
+      ],
+    }
+
+    handler = new RouterBlockHandler({})
+
+    mockContext = {
+      workflowId: 'test-workflow-id',
+      blockStates: new Map(),
+      blockLogs: [],
+      metadata: { duration: 0 },
+      environmentVariables: {},
+      decisions: { router: new Map(), condition: new Map() },
+      loopExecutions: new Map(),
+      completedLoops: new Set(),
+      executedBlocks: new Set(),
+      activeExecutionPath: new Set(),
+      workflow: mockWorkflow as SerializedWorkflow,
+    }
+
+    vi.clearAllMocks()
+
+    mockGetProviderFromModel.mockReturnValue('openai')
+    mockGenerateRouterV2Prompt.mockReturnValue('Generated V2 System Prompt')
+  })
+
+  it('should handle router_v2 blocks', () => {
+    expect(handler.canHandle(mockRouterV2Block)).toBe(true)
+  })
+
+  it('should execute router V2 and return reasoning', async () => {
+    const inputs = {
+      context: 'I need help with a billing issue',
+      model: 'gpt-4o',
+      apiKey: 'test-api-key',
+      routes: JSON.stringify([
+        { id: 'route-support', title: 'Support', value: 'Customer support inquiries' },
+        { id: 'route-sales', title: 'Sales', value: 'Sales and pricing questions' },
+      ]),
+    }
+
+    mockFetch.mockImplementationOnce(() => {
+      return Promise.resolve({
+        ok: true,
+        json: () =>
+          Promise.resolve({
+            content: JSON.stringify({
+              route: 'route-support',
+              reasoning: 'The user mentioned a billing issue which is a customer support matter.',
+            }),
+            model: 'gpt-4o',
+            tokens: { input: 150, output: 25, total: 175 },
+          }),
+      })
+    })
+
+    const result = await handler.execute(mockContext, mockRouterV2Block, inputs)
+
+    expect(result).toMatchObject({
+      context: 'I need help with a billing issue',
+      model: 'gpt-4o',
+      selectedRoute: 'route-support',
+      reasoning: 'The user mentioned a billing issue which is a customer support matter.',
+      selectedPath: {
+        blockId: 'target-block-1',
+        blockType: 'agent',
+        blockTitle: 'Support Agent',
+      },
+    })
+  })
+
+  it('should include responseFormat in provider request', async () => {
+    const inputs = {
+      context: 'Test context',
+      model: 'gpt-4o',
+      apiKey: 'test-api-key',
+      routes: JSON.stringify([{ id: 'route-1', title: 'Route 1', value: 'Description 1' }]),
+    }
+
+    mockFetch.mockImplementationOnce(() => {
+      return Promise.resolve({
+        ok: true,
+        json: () =>
+          Promise.resolve({
+            content: JSON.stringify({ route: 'route-1', reasoning: 'Test reasoning' }),
+            model: 'gpt-4o',
+            tokens: { input: 100, output: 20, total: 120 },
+          }),
+      })
+    })
+
+    await handler.execute(mockContext, mockRouterV2Block, inputs)
+
+    const fetchCallArgs = mockFetch.mock.calls[0]
+    const requestBody = JSON.parse(fetchCallArgs[1].body)
+
+    expect(requestBody.responseFormat).toEqual({
+      name: 'router_response',
+      schema: {
+        type: 'object',
+        properties: {
+          route: {
+            type: 'string',
+            description: 'The selected route ID or NO_MATCH',
+          },
+          reasoning: {
+            type: 'string',
+            description: 'Brief explanation of why this route was chosen',
+          },
+        },
+        required: ['route', 'reasoning'],
+        additionalProperties: false,
+      },
+      strict: true,
+    })
+  })
+
+  it('should handle NO_MATCH response with reasoning', async () => {
+    const inputs = {
+      context: 'Random unrelated query',
+      model: 'gpt-4o',
+      apiKey: 'test-api-key',
+      routes: JSON.stringify([{ id: 'route-1', title: 'Route 1', value: 'Specific topic' }]),
+    }
+
+    mockFetch.mockImplementationOnce(() => {
+      return Promise.resolve({
+        ok: true,
+        json: () =>
+          Promise.resolve({
+            content: JSON.stringify({
+              route: 'NO_MATCH',
+              reasoning: 'The query does not relate to any available route.',
+            }),
+            model: 'gpt-4o',
+            tokens: { input: 100, output: 20, total: 120 },
+          }),
+      })
+    })
+
+    await expect(handler.execute(mockContext, mockRouterV2Block, inputs)).rejects.toThrow(
+      'Router could not determine a matching route: The query does not relate to any available route.'
+    )
+  })
+
+  it('should throw error for invalid route ID in response', async () => {
+    const inputs = {
+      context: 'Test context',
+      model: 'gpt-4o',
+      apiKey: 'test-api-key',
+      routes: JSON.stringify([{ id: 'route-1', title: 'Route 1', value: 'Description' }]),
+    }
+
+    mockFetch.mockImplementationOnce(() => {
+      return Promise.resolve({
+        ok: true,
+        json: () =>
+          Promise.resolve({
+            content: JSON.stringify({ route: 'invalid-route', reasoning: 'Some reasoning' }),
+            model: 'gpt-4o',
+            tokens: { input: 100, output: 20, total: 120 },
+          }),
+      })
+    })
+
+    await expect(handler.execute(mockContext, mockRouterV2Block, inputs)).rejects.toThrow(
+      /Router could not determine a valid route/
+    )
+  })
+
+  it('should handle routes passed as array instead of JSON string', async () => {
+    const inputs = {
+      context: 'Test context',
+      model: 'gpt-4o',
+      apiKey: 'test-api-key',
+      routes: [{ id: 'route-1', title: 'Route 1', value: 'Description' }],
+    }
+
+    mockFetch.mockImplementationOnce(() => {
+      return Promise.resolve({
+        ok: true,
+        json: () =>
+          Promise.resolve({
+            content: JSON.stringify({ route: 'route-1', reasoning: 'Matched route 1' }),
+            model: 'gpt-4o',
+            tokens: { input: 100, output: 20, total: 120 },
+          }),
+      })
+    })
+
+    const result = await handler.execute(mockContext, mockRouterV2Block, inputs)
+
+    expect(result.selectedRoute).toBe('route-1')
+    expect(result.reasoning).toBe('Matched route 1')
+  })
+
+  it('should throw error when no routes are defined', async () => {
+    const inputs = {
+      context: 'Test context',
+      model: 'gpt-4o',
+      apiKey: 'test-api-key',
+      routes: '[]',
+    }
+
+    await expect(handler.execute(mockContext, mockRouterV2Block, inputs)).rejects.toThrow(
+      'No routes defined for router'
+    )
+  })
+
+  it('should handle fallback when JSON parsing fails', async () => {
+    const inputs = {
+      context: 'Test context',
+      model: 'gpt-4o',
+      apiKey: 'test-api-key',
+      routes: JSON.stringify([{ id: 'route-1', title: 'Route 1', value: 'Description' }]),
+    }
+
+    mockFetch.mockImplementationOnce(() => {
+      return Promise.resolve({
+        ok: true,
+        json: () =>
+          Promise.resolve({
+            content: 'route-1',
+            model: 'gpt-4o',
+            tokens: { input: 100, output: 5, total: 105 },
+          }),
+      })
+    })
+
+    const result = await handler.execute(mockContext, mockRouterV2Block, inputs)
+
+    expect(result.selectedRoute).toBe('route-1')
+    expect(result.reasoning).toBe('')
+  })
+})

apps/sim/executor/handlers/router/router-handler.ts

@@ -238,6 +238,25 @@ export class RouterBlockHandler implements BlockHandler {
         apiKey: finalApiKey,
         workflowId: ctx.workflowId,
         workspaceId: ctx.workspaceId,
+        responseFormat: {
+          name: 'router_response',
+          schema: {
+            type: 'object',
+            properties: {
+              route: {
+                type: 'string',
+                description: 'The selected route ID or NO_MATCH',
+              },
+              reasoning: {
+                type: 'string',
+                description: 'Brief explanation of why this route was chosen',
+              },
+            },
+            required: ['route', 'reasoning'],
+            additionalProperties: false,
+          },
+          strict: true,
+        },
       }
 
       if (providerId === 'vertex') {
@@ -277,16 +296,31 @@ export class RouterBlockHandler implements BlockHandler {
 
       const result = await response.json()
 
-      const chosenRouteId = result.content.trim()
+      let chosenRouteId: string
+      let reasoning = ''
+
+      try {
+        const parsedResponse = JSON.parse(result.content)
+        chosenRouteId = parsedResponse.route?.trim() || ''
+        reasoning = parsedResponse.reasoning || ''
+      } catch (_parseError) {
+        logger.error('Router response was not valid JSON despite responseFormat', {
+          content: result.content,
+        })
+        chosenRouteId = result.content.trim()
+      }
 
       if (chosenRouteId === 'NO_MATCH' || chosenRouteId.toUpperCase() === 'NO_MATCH') {
         logger.info('Router determined no route matches the context, routing to error path')
-        throw new Error('Router could not determine a matching route for the given context')
+        throw new Error(
+          reasoning
+            ? `Router could not determine a matching route: ${reasoning}`
+            : 'Router could not determine a matching route for the given context'
+        )
       }
 
       const chosenRoute = routes.find((r) => r.id === chosenRouteId)
 
-      // Throw error if LLM returns invalid route ID - this routes through error path
       if (!chosenRoute) {
         const availableRoutes = routes.map((r) => ({ id: r.id, title: r.title }))
         logger.error(
@@ -298,7 +332,6 @@ export class RouterBlockHandler implements BlockHandler {
         )
       }
 
-      // Find the target block connected to this route's handle
       const connection = ctx.workflow?.connections.find(
         (conn) => conn.source === block.id && conn.sourceHandle === `router-${chosenRoute.id}`
       )
@@ -334,6 +367,7 @@ export class RouterBlockHandler implements BlockHandler {
           total: cost.total,
         },
         selectedRoute: chosenRoute.id,
+        reasoning,
         selectedPath: targetBlock
           ? {
               blockId: targetBlock.id,
@@ -353,7 +387,7 @@ export class RouterBlockHandler implements BlockHandler {
   }
 
   /**
-   * Parse routes from input (can be JSON string or array).
+   * Parse routes from input (can be JSON string or array)
    */
   private parseRoutes(input: any): RouteDefinition[] {
     try {

apps/sim/executor/handlers/workflow/workflow-handler.test.ts

@@ -204,26 +204,21 @@ describe('WorkflowBlockHandler', () => {
       })
     })
 
-    it('should map failed child output correctly', () => {
+    it('should throw error for failed child output so BlockExecutor can check error port', () => {
       const childResult = {
         success: false,
         error: 'Child workflow failed',
       }
 
-      const result = (handler as any).mapChildOutputToParent(
-        childResult,
-        'child-id',
-        'Child Workflow',
-        100
-      )
+      expect(() =>
+        (handler as any).mapChildOutputToParent(childResult, 'child-id', 'Child Workflow', 100)
+      ).toThrow('Error in child workflow "Child Workflow": Child workflow failed')
 
-      expect(result).toEqual({
-        success: false,
-        childWorkflowName: 'Child Workflow',
-        result: {},
-        error: 'Child workflow failed',
-        childTraceSpans: [],
-      })
+      try {
+        ;(handler as any).mapChildOutputToParent(childResult, 'child-id', 'Child Workflow', 100)
+      } catch (error: any) {
+        expect(error.childTraceSpans).toEqual([])
+      }
     })
 
     it('should handle nested response structures', () => {

apps/sim/executor/handlers/workflow/workflow-handler.ts

@@ -144,6 +144,11 @@ export class WorkflowBlockHandler implements BlockHandler {
       const workflowMetadata = workflows[workflowId]
       const childWorkflowName = workflowMetadata?.name || workflowId
 
+      const originalError = error.message || 'Unknown error'
+      const wrappedError = new Error(
+        `Error in child workflow "${childWorkflowName}": ${originalError}`
+      )
+
       if (error.executionResult?.logs) {
         const executionResult = error.executionResult as ExecutionResult
 
@@ -159,28 +164,12 @@ export class WorkflowBlockHandler implements BlockHandler {
         )
 
         logger.info(`Captured ${childTraceSpans.length} child trace spans from failed execution`)
-
-        return {
-          success: false,
-          childWorkflowName,
-          result: {},
-          error: error.message || 'Child workflow execution failed',
-          childTraceSpans: childTraceSpans,
-        } as Record<string, any>
+        ;(wrappedError as any).childTraceSpans = childTraceSpans
+      } else if (error.childTraceSpans && Array.isArray(error.childTraceSpans)) {
+        ;(wrappedError as any).childTraceSpans = error.childTraceSpans
       }
 
-      if (error.childTraceSpans && Array.isArray(error.childTraceSpans)) {
-        return {
-          success: false,
-          childWorkflowName,
-          result: {},
-          error: error.message || 'Child workflow execution failed',
-          childTraceSpans: error.childTraceSpans,
-        } as Record<string, any>
-      }
-
-      const originalError = error.message || 'Unknown error'
-      throw new Error(`Error in child workflow "${childWorkflowName}": ${originalError}`)
+      throw wrappedError
     }
   }
 
@@ -452,17 +441,13 @@ export class WorkflowBlockHandler implements BlockHandler {
 
     if (!success) {
       logger.warn(`Child workflow ${childWorkflowName} failed`)
-      // Return failure with child trace spans so they can be displayed
-      return {
-        success: false,
-        childWorkflowName,
-        result,
-        error: childResult.error || 'Child workflow execution failed',
-        childTraceSpans: childTraceSpans || [],
-      } as Record<string, any>
+      const error = new Error(
+        `Error in child workflow "${childWorkflowName}": ${childResult.error || 'Child workflow execution failed'}`
+      )
+      ;(error as any).childTraceSpans = childTraceSpans || []
+      throw error
     }
 
-    // Success case
     return {
       success: true,
       childWorkflowName,

apps/sim/executor/utils/block-data.ts

@@ -1,24 +1,43 @@
+import { getBlockOutputs } from '@/lib/workflows/blocks/block-outputs'
 import { normalizeName } from '@/executor/constants'
 import type { ExecutionContext } from '@/executor/types'
+import type { OutputSchema } from '@/executor/utils/block-reference'
 
 export interface BlockDataCollection {
-  blockData: Record<string, any>
+  blockData: Record<string, unknown>
   blockNameMapping: Record<string, string>
+  blockOutputSchemas: Record<string, OutputSchema>
 }
 
 export function collectBlockData(ctx: ExecutionContext): BlockDataCollection {
-  const blockData: Record<string, any> = {}
+  const blockData: Record<string, unknown> = {}
   const blockNameMapping: Record<string, string> = {}
+  const blockOutputSchemas: Record<string, OutputSchema> = {}
 
   for (const [id, state] of ctx.blockStates.entries()) {
     if (state.output !== undefined) {
       blockData[id] = state.output
-      const workflowBlock = ctx.workflow?.blocks?.find((b) => b.id === id)
-      if (workflowBlock?.metadata?.name) {
-        blockNameMapping[normalizeName(workflowBlock.metadata.name)] = id
+    }
+
+    const workflowBlock = ctx.workflow?.blocks?.find((b) => b.id === id)
+    if (!workflowBlock) continue
+
+    if (workflowBlock.metadata?.name) {
+      blockNameMapping[normalizeName(workflowBlock.metadata.name)] = id
+    }
+
+    const blockType = workflowBlock.metadata?.id
+    if (blockType) {
+      const params = workflowBlock.config?.params as Record<string, unknown> | undefined
+      const subBlocks = params
+        ? Object.fromEntries(Object.entries(params).map(([k, v]) => [k, { value: v }]))
+        : undefined
+      const schema = getBlockOutputs(blockType, subBlocks)
+      if (schema && Object.keys(schema).length > 0) {
+        blockOutputSchemas[id] = schema
       }
     }
   }
 
-  return { blockData, blockNameMapping }
+  return { blockData, blockNameMapping, blockOutputSchemas }
 }

apps/sim/executor/utils/block-reference.test.ts

@@ -0,0 +1,255 @@
+/**
+ * @vitest-environment node
+ */
+import { describe, expect, it } from 'vitest'
+import {
+  type BlockReferenceContext,
+  InvalidFieldError,
+  resolveBlockReference,
+} from './block-reference'
+
+describe('resolveBlockReference', () => {
+  const createContext = (
+    overrides: Partial<BlockReferenceContext> = {}
+  ): BlockReferenceContext => ({
+    blockNameMapping: { start: 'block-1', agent: 'block-2' },
+    blockData: {},
+    blockOutputSchemas: {},
+    ...overrides,
+  })
+
+  describe('block name resolution', () => {
+    it('should return undefined when block name does not exist', () => {
+      const ctx = createContext()
+      const result = resolveBlockReference('unknown', ['field'], ctx)
+      expect(result).toBeUndefined()
+    })
+
+    it('should normalize block name before lookup', () => {
+      const ctx = createContext({
+        blockNameMapping: { myblock: 'block-1' },
+        blockData: { 'block-1': { value: 'test' } },
+      })
+
+      const result = resolveBlockReference('MyBlock', ['value'], ctx)
+      expect(result).toEqual({ value: 'test', blockId: 'block-1' })
+    })
+
+    it('should handle block names with spaces', () => {
+      const ctx = createContext({
+        blockNameMapping: { myblock: 'block-1' },
+        blockData: { 'block-1': { value: 'test' } },
+      })
+
+      const result = resolveBlockReference('My Block', ['value'], ctx)
+      expect(result).toEqual({ value: 'test', blockId: 'block-1' })
+    })
+  })
+
+  describe('field resolution', () => {
+    it('should return entire block output when no path specified', () => {
+      const ctx = createContext({
+        blockData: { 'block-1': { input: 'hello', other: 'data' } },
+      })
+
+      const result = resolveBlockReference('start', [], ctx)
+      expect(result).toEqual({
+        value: { input: 'hello', other: 'data' },
+        blockId: 'block-1',
+      })
+    })
+
+    it('should resolve simple field path', () => {
+      const ctx = createContext({
+        blockData: { 'block-1': { input: 'hello' } },
+      })
+
+      const result = resolveBlockReference('start', ['input'], ctx)
+      expect(result).toEqual({ value: 'hello', blockId: 'block-1' })
+    })
+
+    it('should resolve nested field path', () => {
+      const ctx = createContext({
+        blockData: { 'block-1': { response: { data: { name: 'test' } } } },
+      })
+
+      const result = resolveBlockReference('start', ['response', 'data', 'name'], ctx)
+      expect(result).toEqual({ value: 'test', blockId: 'block-1' })
+    })
+
+    it('should resolve array index path', () => {
+      const ctx = createContext({
+        blockData: { 'block-1': { items: ['a', 'b', 'c'] } },
+      })
+
+      const result = resolveBlockReference('start', ['items', '1'], ctx)
+      expect(result).toEqual({ value: 'b', blockId: 'block-1' })
+    })
+
+    it('should return undefined value when field exists but has no value', () => {
+      const ctx = createContext({
+        blockData: { 'block-1': { input: undefined } },
+        blockOutputSchemas: {
+          'block-1': { input: { type: 'string' } },
+        },
+      })
+
+      const result = resolveBlockReference('start', ['input'], ctx)
+      expect(result).toEqual({ value: undefined, blockId: 'block-1' })
+    })
+
+    it('should return null value when field has null', () => {
+      const ctx = createContext({
+        blockData: { 'block-1': { input: null } },
+      })
+
+      const result = resolveBlockReference('start', ['input'], ctx)
+      expect(result).toEqual({ value: null, blockId: 'block-1' })
+    })
+  })
+
+  describe('schema validation', () => {
+    it('should throw InvalidFieldError when field not in schema', () => {
+      const ctx = createContext({
+        blockData: { 'block-1': { existing: 'value' } },
+        blockOutputSchemas: {
+          'block-1': {
+            input: { type: 'string' },
+            conversationId: { type: 'string' },
+          },
+        },
+      })
+
+      expect(() => resolveBlockReference('start', ['invalid'], ctx)).toThrow(InvalidFieldError)
+      expect(() => resolveBlockReference('start', ['invalid'], ctx)).toThrow(
+        /"invalid" doesn't exist on block "start"/
+      )
+    })
+
+    it('should include available fields in error message', () => {
+      const ctx = createContext({
+        blockData: { 'block-1': {} },
+        blockOutputSchemas: {
+          'block-1': {
+            input: { type: 'string' },
+            conversationId: { type: 'string' },
+            files: { type: 'files' },
+          },
+        },
+      })
+
+      try {
+        resolveBlockReference('start', ['typo'], ctx)
+        expect.fail('Should have thrown')
+      } catch (error) {
+        expect(error).toBeInstanceOf(InvalidFieldError)
+        const fieldError = error as InvalidFieldError
+        expect(fieldError.availableFields).toContain('input')
+        expect(fieldError.availableFields).toContain('conversationId')
+        expect(fieldError.availableFields).toContain('files')
+      }
+    })
+
+    it('should allow valid field even when value is undefined', () => {
+      const ctx = createContext({
+        blockData: { 'block-1': {} },
+        blockOutputSchemas: {
+          'block-1': { input: { type: 'string' } },
+        },
+      })
+
+      const result = resolveBlockReference('start', ['input'], ctx)
+      expect(result).toEqual({ value: undefined, blockId: 'block-1' })
+    })
+
+    it('should validate path when block has no output yet', () => {
+      const ctx = createContext({
+        blockData: {},
+        blockOutputSchemas: {
+          'block-1': { input: { type: 'string' } },
+        },
+      })
+
+      expect(() => resolveBlockReference('start', ['invalid'], ctx)).toThrow(InvalidFieldError)
+    })
+
+    it('should return undefined for valid field when block has no output', () => {
+      const ctx = createContext({
+        blockData: {},
+        blockOutputSchemas: {
+          'block-1': { input: { type: 'string' } },
+        },
+      })
+
+      const result = resolveBlockReference('start', ['input'], ctx)
+      expect(result).toEqual({ value: undefined, blockId: 'block-1' })
+    })
+  })
+
+  describe('without schema (pass-through mode)', () => {
+    it('should return undefined value without throwing when no schema', () => {
+      const ctx = createContext({
+        blockData: { 'block-1': { existing: 'value' } },
+      })
+
+      const result = resolveBlockReference('start', ['missing'], ctx)
+      expect(result).toEqual({ value: undefined, blockId: 'block-1' })
+    })
+  })
+
+  describe('file type handling', () => {
+    it('should allow file property access', () => {
+      const ctx = createContext({
+        blockData: {
+          'block-1': {
+            files: [{ name: 'test.txt', url: 'http://example.com/file' }],
+          },
+        },
+        blockOutputSchemas: {
+          'block-1': { files: { type: 'files' } },
+        },
+      })
+
+      const result = resolveBlockReference('start', ['files', '0', 'name'], ctx)
+      expect(result).toEqual({ value: 'test.txt', blockId: 'block-1' })
+    })
+
+    it('should validate file property names', () => {
+      const ctx = createContext({
+        blockData: { 'block-1': { files: [] } },
+        blockOutputSchemas: {
+          'block-1': { files: { type: 'files' } },
+        },
+      })
+
+      expect(() => resolveBlockReference('start', ['files', '0', 'invalid'], ctx)).toThrow(
+        InvalidFieldError
+      )
+    })
+  })
+})
+
+describe('InvalidFieldError', () => {
+  it('should have correct properties', () => {
+    const error = new InvalidFieldError('myBlock', 'invalid.path', ['field1', 'field2'])
+
+    expect(error.blockName).toBe('myBlock')
+    expect(error.fieldPath).toBe('invalid.path')
+    expect(error.availableFields).toEqual(['field1', 'field2'])
+    expect(error.name).toBe('InvalidFieldError')
+  })
+
+  it('should format message correctly', () => {
+    const error = new InvalidFieldError('start', 'typo', ['input', 'files'])
+
+    expect(error.message).toBe(
+      '"typo" doesn\'t exist on block "start". Available fields: input, files'
+    )
+  })
+
+  it('should handle empty available fields', () => {
+    const error = new InvalidFieldError('start', 'field', [])
+
+    expect(error.message).toBe('"field" doesn\'t exist on block "start". Available fields: none')
+  })
+})

apps/sim/executor/utils/block-reference.ts

@@ -0,0 +1,210 @@
+import { USER_FILE_ACCESSIBLE_PROPERTIES } from '@/lib/workflows/types'
+import { normalizeName } from '@/executor/constants'
+import { navigatePath } from '@/executor/variables/resolvers/reference'
+
+export type OutputSchema = Record<string, { type?: string; description?: string } | unknown>
+
+export interface BlockReferenceContext {
+  blockNameMapping: Record<string, string>
+  blockData: Record<string, unknown>
+  blockOutputSchemas?: Record<string, OutputSchema>
+}
+
+export interface BlockReferenceResult {
+  value: unknown
+  blockId: string
+}
+
+export class InvalidFieldError extends Error {
+  constructor(
+    public readonly blockName: string,
+    public readonly fieldPath: string,
+    public readonly availableFields: string[]
+  ) {
+    super(
+      `"${fieldPath}" doesn't exist on block "${blockName}". ` +
+        `Available fields: ${availableFields.length > 0 ? availableFields.join(', ') : 'none'}`
+    )
+    this.name = 'InvalidFieldError'
+  }
+}
+
+function isFileType(value: unknown): boolean {
+  if (typeof value !== 'object' || value === null) return false
+  const typed = value as { type?: string }
+  return typed.type === 'file[]' || typed.type === 'files'
+}
+
+function isArrayType(value: unknown): value is { type: 'array'; items?: unknown } {
+  if (typeof value !== 'object' || value === null) return false
+  return (value as { type?: string }).type === 'array'
+}
+
+function getArrayItems(schema: unknown): unknown {
+  if (typeof schema !== 'object' || schema === null) return undefined
+  return (schema as { items?: unknown }).items
+}
+
+function getProperties(schema: unknown): Record<string, unknown> | undefined {
+  if (typeof schema !== 'object' || schema === null) return undefined
+  const props = (schema as { properties?: unknown }).properties
+  return typeof props === 'object' && props !== null
+    ? (props as Record<string, unknown>)
+    : undefined
+}
+
+function lookupField(schema: unknown, fieldName: string): unknown | undefined {
+  if (typeof schema !== 'object' || schema === null) return undefined
+  const typed = schema as Record<string, unknown>
+
+  if (fieldName in typed) {
+    return typed[fieldName]
+  }
+
+  const props = getProperties(schema)
+  if (props && fieldName in props) {
+    return props[fieldName]
+  }
+
+  return undefined
+}
+
+function isPathInSchema(schema: OutputSchema | undefined, pathParts: string[]): boolean {
+  if (!schema || pathParts.length === 0) {
+    return true
+  }
+
+  let current: unknown = schema
+
+  for (let i = 0; i < pathParts.length; i++) {
+    const part = pathParts[i]
+
+    if (current === null || current === undefined) {
+      return false
+    }
+
+    if (/^\d+$/.test(part)) {
+      if (isFileType(current)) {
+        const nextPart = pathParts[i + 1]
+        return (
+          !nextPart ||
+          USER_FILE_ACCESSIBLE_PROPERTIES.includes(
+            nextPart as (typeof USER_FILE_ACCESSIBLE_PROPERTIES)[number]
+          )
+        )
+      }
+      if (isArrayType(current)) {
+        current = getArrayItems(current)
+      }
+      continue
+    }
+
+    const arrayMatch = part.match(/^([^[]+)\[(\d+)\]$/)
+    if (arrayMatch) {
+      const [, prop] = arrayMatch
+      const fieldDef = lookupField(current, prop)
+      if (!fieldDef) return false
+
+      if (isFileType(fieldDef)) {
+        const nextPart = pathParts[i + 1]
+        return (
+          !nextPart ||
+          USER_FILE_ACCESSIBLE_PROPERTIES.includes(
+            nextPart as (typeof USER_FILE_ACCESSIBLE_PROPERTIES)[number]
+          )
+        )
+      }
+
+      current = isArrayType(fieldDef) ? getArrayItems(fieldDef) : fieldDef
+      continue
+    }
+
+    if (
+      isFileType(current) &&
+      USER_FILE_ACCESSIBLE_PROPERTIES.includes(
+        part as (typeof USER_FILE_ACCESSIBLE_PROPERTIES)[number]
+      )
+    ) {
+      return true
+    }
+
+    const fieldDef = lookupField(current, part)
+    if (fieldDef !== undefined) {
+      if (isFileType(fieldDef)) {
+        const nextPart = pathParts[i + 1]
+        if (!nextPart) return true
+        if (/^\d+$/.test(nextPart)) {
+          const afterIndex = pathParts[i + 2]
+          return (
+            !afterIndex ||
+            USER_FILE_ACCESSIBLE_PROPERTIES.includes(
+              afterIndex as (typeof USER_FILE_ACCESSIBLE_PROPERTIES)[number]
+            )
+          )
+        }
+        return USER_FILE_ACCESSIBLE_PROPERTIES.includes(
+          nextPart as (typeof USER_FILE_ACCESSIBLE_PROPERTIES)[number]
+        )
+      }
+      current = fieldDef
+      continue
+    }
+
+    if (isArrayType(current)) {
+      const items = getArrayItems(current)
+      const itemField = lookupField(items, part)
+      if (itemField !== undefined) {
+        current = itemField
+        continue
+      }
+    }
+
+    return false
+  }
+
+  return true
+}
+
+function getSchemaFieldNames(schema: OutputSchema | undefined): string[] {
+  if (!schema) return []
+  return Object.keys(schema)
+}
+
+export function resolveBlockReference(
+  blockName: string,
+  pathParts: string[],
+  context: BlockReferenceContext
+): BlockReferenceResult | undefined {
+  const normalizedName = normalizeName(blockName)
+  const blockId = context.blockNameMapping[normalizedName]
+
+  if (!blockId) {
+    return undefined
+  }
+
+  const blockOutput = context.blockData[blockId]
+  const schema = context.blockOutputSchemas?.[blockId]
+
+  if (blockOutput === undefined) {
+    if (schema && pathParts.length > 0) {
+      if (!isPathInSchema(schema, pathParts)) {
+        throw new InvalidFieldError(blockName, pathParts.join('.'), getSchemaFieldNames(schema))
+      }
+    }
+    return { value: undefined, blockId }
+  }
+
+  if (pathParts.length === 0) {
+    return { value: blockOutput, blockId }
+  }
+
+  const value = navigatePath(blockOutput, pathParts)
+
+  if (value === undefined && schema) {
+    if (!isPathInSchema(schema, pathParts)) {
+      throw new InvalidFieldError(blockName, pathParts.join('.'), getSchemaFieldNames(schema))
+    }
+  }
+
+  return { value, blockId }
+}

apps/sim/executor/variables/resolvers/block.ts

@@ -1,11 +1,15 @@
 import { getBlockOutputs } from '@/lib/workflows/blocks/block-outputs'
-import { USER_FILE_ACCESSIBLE_PROPERTIES } from '@/lib/workflows/types'
 import {
   isReference,
   normalizeName,
   parseReferencePath,
   SPECIAL_REFERENCE_PREFIXES,
 } from '@/executor/constants'
+import {
+  InvalidFieldError,
+  type OutputSchema,
+  resolveBlockReference,
+} from '@/executor/utils/block-reference'
 import {
   navigatePath,
   type ResolutionContext,
@@ -14,123 +18,6 @@ import {
 import type { SerializedBlock, SerializedWorkflow } from '@/serializer/types'
 import { getTool } from '@/tools/utils'
 
-function isPathInOutputSchema(
-  outputs: Record<string, any> | undefined,
-  pathParts: string[]
-): boolean {
-  if (!outputs || pathParts.length === 0) {
-    return true
-  }
-
-  const isFileArrayType = (value: any): boolean =>
-    value?.type === 'file[]' || value?.type === 'files'
-
-  let current: any = outputs
-  for (let i = 0; i < pathParts.length; i++) {
-    const part = pathParts[i]
-
-    const arrayMatch = part.match(/^([^[]+)\[(\d+)\]$/)
-    if (arrayMatch) {
-      const [, prop] = arrayMatch
-      let fieldDef: any
-
-      if (prop in current) {
-        fieldDef = current[prop]
-      } else if (current.properties && prop in current.properties) {
-        fieldDef = current.properties[prop]
-      } else if (current.type === 'array' && current.items) {
-        if (current.items.properties && prop in current.items.properties) {
-          fieldDef = current.items.properties[prop]
-        } else if (prop in current.items) {
-          fieldDef = current.items[prop]
-        }
-      }
-
-      if (!fieldDef) {
-        return false
-      }
-
-      if (isFileArrayType(fieldDef)) {
-        if (i + 1 < pathParts.length) {
-          return USER_FILE_ACCESSIBLE_PROPERTIES.includes(pathParts[i + 1] as any)
-        }
-        return true
-      }
-
-      if (fieldDef.type === 'array' && fieldDef.items) {
-        current = fieldDef.items
-        continue
-      }
-
-      current = fieldDef
-      continue
-    }
-
-    if (/^\d+$/.test(part)) {
-      if (isFileArrayType(current)) {
-        if (i + 1 < pathParts.length) {
-          const nextPart = pathParts[i + 1]
-          return USER_FILE_ACCESSIBLE_PROPERTIES.includes(nextPart as any)
-        }
-        return true
-      }
-      continue
-    }
-
-    if (current === null || current === undefined) {
-      return false
-    }
-
-    if (part in current) {
-      const nextCurrent = current[part]
-      if (nextCurrent?.type === 'file[]' && i + 1 < pathParts.length) {
-        const nextPart = pathParts[i + 1]
-        if (/^\d+$/.test(nextPart) && i + 2 < pathParts.length) {
-          const propertyPart = pathParts[i + 2]
-          return USER_FILE_ACCESSIBLE_PROPERTIES.includes(propertyPart as any)
-        }
-      }
-      current = nextCurrent
-      continue
-    }
-
-    if (current.properties && part in current.properties) {
-      current = current.properties[part]
-      continue
-    }
-
-    if (current.type === 'array' && current.items) {
-      if (current.items.properties && part in current.items.properties) {
-        current = current.items.properties[part]
-        continue
-      }
-      if (part in current.items) {
-        current = current.items[part]
-        continue
-      }
-    }
-
-    if (isFileArrayType(current) && USER_FILE_ACCESSIBLE_PROPERTIES.includes(part as any)) {
-      return true
-    }
-
-    if ('type' in current && typeof current.type === 'string') {
-      if (!current.properties && !current.items) {
-        return false
-      }
-    }
-
-    return false
-  }
-
-  return true
-}
-
-function getSchemaFieldNames(outputs: Record<string, any> | undefined): string[] {
-  if (!outputs) return []
-  return Object.keys(outputs)
-}
-
 export class BlockResolver implements Resolver {
   private nameToBlockId: Map<string, string>
   private blockById: Map<string, SerializedBlock>
@@ -170,83 +57,94 @@ export class BlockResolver implements Resolver {
       return undefined
     }
 
-    const block = this.blockById.get(blockId)
+    const block = this.blockById.get(blockId)!
     const output = this.getBlockOutput(blockId, context)
 
-    if (output === undefined) {
+    const blockData: Record<string, unknown> = {}
+    const blockOutputSchemas: Record<string, OutputSchema> = {}
+
+    if (output !== undefined) {
+      blockData[blockId] = output
+    }
+
+    const blockType = block.metadata?.id
+    const params = block.config?.params as Record<string, unknown> | undefined
+    const subBlocks = params
+      ? Object.fromEntries(Object.entries(params).map(([k, v]) => [k, { value: v }]))
+      : undefined
+    const toolId = block.config?.tool
+    const toolConfig = toolId ? getTool(toolId) : undefined
+    const outputSchema =
+      toolConfig?.outputs ?? (blockType ? getBlockOutputs(blockType, subBlocks) : block.outputs)
+
+    if (outputSchema && Object.keys(outputSchema).length > 0) {
+      blockOutputSchemas[blockId] = outputSchema
+    }
+
+    try {
+      const result = resolveBlockReference(blockName, pathParts, {
+        blockNameMapping: Object.fromEntries(this.nameToBlockId),
+        blockData,
+        blockOutputSchemas,
+      })!
+
+      if (result.value !== undefined) {
+        return result.value
+      }
+
+      return this.handleBackwardsCompat(block, output, pathParts)
+    } catch (error) {
+      if (error instanceof InvalidFieldError) {
+        const fallback = this.handleBackwardsCompat(block, output, pathParts)
+        if (fallback !== undefined) {
+          return fallback
+        }
+        throw new Error(error.message)
+      }
+      throw error
+    }
+  }
+
+  private handleBackwardsCompat(
+    block: SerializedBlock,
+    output: unknown,
+    pathParts: string[]
+  ): unknown {
+    if (output === undefined || pathParts.length === 0) {
       return undefined
     }
-    if (pathParts.length === 0) {
-      return output
-    }
 
-    // Try the original path first
-    let result = navigatePath(output, pathParts)
-
-    // If successful, return it immediately
-    if (result !== undefined) {
-      return result
-    }
-
-    // Response block backwards compatibility:
-    // Old: <responseBlock.response.data> -> New: <responseBlock.data>
-    // Only apply fallback if:
-    // 1. Block type is 'response'
-    // 2. Path starts with 'response.'
-    // 3. Output doesn't have a 'response' key (confirming it's the new format)
     if (
-      block?.metadata?.id === 'response' &&
+      block.metadata?.id === 'response' &&
       pathParts[0] === 'response' &&
-      output?.response === undefined
+      (output as Record<string, unknown>)?.response === undefined
     ) {
       const adjustedPathParts = pathParts.slice(1)
       if (adjustedPathParts.length === 0) {
         return output
       }
-      result = navigatePath(output, adjustedPathParts)
-      if (result !== undefined) {
-        return result
+      const fallbackResult = navigatePath(output, adjustedPathParts)
+      if (fallbackResult !== undefined) {
+        return fallbackResult
       }
     }
 
-    // Workflow block backwards compatibility:
-    // Old: <workflowBlock.result.response.data> -> New: <workflowBlock.result.data>
-    // Only apply fallback if:
-    // 1. Block type is 'workflow' or 'workflow_input'
-    // 2. Path starts with 'result.response.'
-    // 3. output.result.response doesn't exist (confirming child used new format)
     const isWorkflowBlock =
-      block?.metadata?.id === 'workflow' || block?.metadata?.id === 'workflow_input'
+      block.metadata?.id === 'workflow' || block.metadata?.id === 'workflow_input'
+    const outputRecord = output as Record<string, Record<string, unknown> | undefined>
     if (
       isWorkflowBlock &&
       pathParts[0] === 'result' &&
       pathParts[1] === 'response' &&
-      output?.result?.response === undefined
+      outputRecord?.result?.response === undefined
     ) {
       const adjustedPathParts = ['result', ...pathParts.slice(2)]
-      result = navigatePath(output, adjustedPathParts)
-      if (result !== undefined) {
-        return result
+      const fallbackResult = navigatePath(output, adjustedPathParts)
+      if (fallbackResult !== undefined) {
+        return fallbackResult
       }
     }
 
-    const blockType = block?.metadata?.id
-    const params = block?.config?.params as Record<string, unknown> | undefined
-    const subBlocks = params
-      ? Object.fromEntries(Object.entries(params).map(([k, v]) => [k, { value: v }]))
-      : undefined
-    const toolId = block?.config?.tool
-    const toolConfig = toolId ? getTool(toolId) : undefined
-    const outputSchema =
-      toolConfig?.outputs ?? (blockType ? getBlockOutputs(blockType, subBlocks) : block?.outputs)
-    const schemaFields = getSchemaFieldNames(outputSchema)
-    if (schemaFields.length > 0 && !isPathInOutputSchema(outputSchema, pathParts)) {
-      throw new Error(
-        `"${pathParts.join('.')}" doesn't exist on block "${blockName}". ` +
-          `Available fields: ${schemaFields.join(', ')}`
-      )
-    }
-
     return undefined
   }
 

apps/sim/executor/variables/resolvers/loop.test.ts

@@ -1,6 +1,7 @@
 import { loggerMock } from '@sim/testing'
 import { describe, expect, it, vi } from 'vitest'
 import type { LoopScope } from '@/executor/execution/state'
+import { InvalidFieldError } from '@/executor/utils/block-reference'
 import { LoopResolver } from './loop'
 import type { ResolutionContext } from './reference'
 
@@ -62,7 +63,12 @@ function createTestContext(
 
 describe('LoopResolver', () => {
   describe('canResolve', () => {
-    it.concurrent('should return true for loop references', () => {
+    it.concurrent('should return true for bare loop reference', () => {
+      const resolver = new LoopResolver(createTestWorkflow())
+      expect(resolver.canResolve('<loop>')).toBe(true)
+    })
+
+    it.concurrent('should return true for known loop properties', () => {
       const resolver = new LoopResolver(createTestWorkflow())
       expect(resolver.canResolve('<loop.index>')).toBe(true)
       expect(resolver.canResolve('<loop.iteration>')).toBe(true)
@@ -78,6 +84,13 @@ describe('LoopResolver', () => {
       expect(resolver.canResolve('<loop.items.0>')).toBe(true)
     })
 
+    it.concurrent('should return true for unknown loop properties (validates in resolve)', () => {
+      const resolver = new LoopResolver(createTestWorkflow())
+      expect(resolver.canResolve('<loop.results>')).toBe(true)
+      expect(resolver.canResolve('<loop.output>')).toBe(true)
+      expect(resolver.canResolve('<loop.unknownProperty>')).toBe(true)
+    })
+
     it.concurrent('should return false for non-loop references', () => {
       const resolver = new LoopResolver(createTestWorkflow())
       expect(resolver.canResolve('<block.output>')).toBe(false)
@@ -181,20 +194,34 @@ describe('LoopResolver', () => {
   })
 
   describe('edge cases', () => {
-    it.concurrent('should return undefined for invalid loop reference (missing property)', () => {
+    it.concurrent('should return context object for bare loop reference', () => {
       const resolver = new LoopResolver(createTestWorkflow())
-      const loopScope = createLoopScope({ iteration: 0 })
+      const loopScope = createLoopScope({ iteration: 2, item: 'test', items: ['a', 'b', 'c'] })
       const ctx = createTestContext('block-1', loopScope)
 
-      expect(resolver.resolve('<loop>', ctx)).toBeUndefined()
+      expect(resolver.resolve('<loop>', ctx)).toEqual({
+        index: 2,
+        currentItem: 'test',
+        items: ['a', 'b', 'c'],
+      })
     })
 
-    it.concurrent('should return undefined for unknown loop property', () => {
+    it.concurrent('should return minimal context object for for-loop (no items)', () => {
+      const resolver = new LoopResolver(createTestWorkflow())
+      const loopScope = createLoopScope({ iteration: 5 })
+      const ctx = createTestContext('block-1', loopScope)
+
+      expect(resolver.resolve('<loop>', ctx)).toEqual({
+        index: 5,
+      })
+    })
+
+    it.concurrent('should throw InvalidFieldError for unknown loop property', () => {
       const resolver = new LoopResolver(createTestWorkflow())
       const loopScope = createLoopScope({ iteration: 0 })
       const ctx = createTestContext('block-1', loopScope)
 
-      expect(resolver.resolve('<loop.unknownProperty>', ctx)).toBeUndefined()
+      expect(() => resolver.resolve('<loop.unknownProperty>', ctx)).toThrow(InvalidFieldError)
     })
 
     it.concurrent('should handle iteration index 0 correctly', () => {

apps/sim/executor/variables/resolvers/loop.ts

@@ -1,5 +1,6 @@
 import { createLogger } from '@sim/logger'
 import { isReference, parseReferencePath, REFERENCE } from '@/executor/constants'
+import { InvalidFieldError } from '@/executor/utils/block-reference'
 import { extractBaseBlockId } from '@/executor/utils/subflow-utils'
 import {
   navigatePath,
@@ -13,6 +14,8 @@ const logger = createLogger('LoopResolver')
 export class LoopResolver implements Resolver {
   constructor(private workflow: SerializedWorkflow) {}
 
+  private static KNOWN_PROPERTIES = ['iteration', 'index', 'item', 'currentItem', 'items']
+
   canResolve(reference: string): boolean {
     if (!isReference(reference)) {
       return false
@@ -27,16 +30,15 @@ export class LoopResolver implements Resolver {
 
   resolve(reference: string, context: ResolutionContext): any {
     const parts = parseReferencePath(reference)
-    if (parts.length < 2) {
-      logger.warn('Invalid loop reference - missing property', { reference })
+    if (parts.length === 0) {
+      logger.warn('Invalid loop reference', { reference })
       return undefined
     }
 
-    const [_, property, ...pathParts] = parts
+    const loopId = this.findLoopForBlock(context.currentNodeId)
     let loopScope = context.loopScope
 
     if (!loopScope) {
-      const loopId = this.findLoopForBlock(context.currentNodeId)
       if (!loopId) {
         return undefined
       }
@@ -48,6 +50,27 @@ export class LoopResolver implements Resolver {
       return undefined
     }
 
+    const isForEach = loopId ? this.isForEachLoop(loopId) : loopScope.items !== undefined
+
+    if (parts.length === 1) {
+      const result: Record<string, any> = {
+        index: loopScope.iteration,
+      }
+      if (loopScope.item !== undefined) {
+        result.currentItem = loopScope.item
+      }
+      if (loopScope.items !== undefined) {
+        result.items = loopScope.items
+      }
+      return result
+    }
+
+    const [_, property, ...pathParts] = parts
+    if (!LoopResolver.KNOWN_PROPERTIES.includes(property)) {
+      const availableFields = isForEach ? ['index', 'currentItem', 'items'] : ['index']
+      throw new InvalidFieldError('loop', property, availableFields)
+    }
+
     let value: any
     switch (property) {
       case 'iteration':
@@ -61,12 +84,8 @@ export class LoopResolver implements Resolver {
       case 'items':
         value = loopScope.items
         break
-      default:
-        logger.warn('Unknown loop property', { property })
-        return undefined
     }
 
-    // If there are additional path parts, navigate deeper
     if (pathParts.length > 0) {
       return navigatePath(value, pathParts)
     }
@@ -85,4 +104,9 @@ export class LoopResolver implements Resolver {
 
     return undefined
   }
+
+  private isForEachLoop(loopId: string): boolean {
+    const loopConfig = this.workflow.loops?.[loopId]
+    return loopConfig?.loopType === 'forEach'
+  }
 }

apps/sim/executor/variables/resolvers/parallel.test.ts

@@ -1,5 +1,6 @@
 import { loggerMock } from '@sim/testing'
 import { describe, expect, it, vi } from 'vitest'
+import { InvalidFieldError } from '@/executor/utils/block-reference'
 import { ParallelResolver } from './parallel'
 import type { ResolutionContext } from './reference'
 
@@ -81,7 +82,12 @@ function createTestContext(
 
 describe('ParallelResolver', () => {
   describe('canResolve', () => {
-    it.concurrent('should return true for parallel references', () => {
+    it.concurrent('should return true for bare parallel reference', () => {
+      const resolver = new ParallelResolver(createTestWorkflow())
+      expect(resolver.canResolve('<parallel>')).toBe(true)
+    })
+
+    it.concurrent('should return true for known parallel properties', () => {
       const resolver = new ParallelResolver(createTestWorkflow())
       expect(resolver.canResolve('<parallel.index>')).toBe(true)
       expect(resolver.canResolve('<parallel.currentItem>')).toBe(true)
@@ -94,6 +100,16 @@ describe('ParallelResolver', () => {
       expect(resolver.canResolve('<parallel.items.0>')).toBe(true)
     })
 
+    it.concurrent(
+      'should return true for unknown parallel properties (validates in resolve)',
+      () => {
+        const resolver = new ParallelResolver(createTestWorkflow())
+        expect(resolver.canResolve('<parallel.results>')).toBe(true)
+        expect(resolver.canResolve('<parallel.output>')).toBe(true)
+        expect(resolver.canResolve('<parallel.unknownProperty>')).toBe(true)
+      }
+    )
+
     it.concurrent('should return false for non-parallel references', () => {
       const resolver = new ParallelResolver(createTestWorkflow())
       expect(resolver.canResolve('<block.output>')).toBe(false)
@@ -254,24 +270,40 @@ describe('ParallelResolver', () => {
   })
 
   describe('edge cases', () => {
-    it.concurrent(
-      'should return undefined for invalid parallel reference (missing property)',
-      () => {
-        const resolver = new ParallelResolver(createTestWorkflow())
-        const ctx = createTestContext('block-1₍0₎')
+    it.concurrent('should return context object for bare parallel reference', () => {
+      const workflow = createTestWorkflow({
+        'parallel-1': { nodes: ['block-1'], distribution: ['a', 'b', 'c'] },
+      })
+      const resolver = new ParallelResolver(workflow)
+      const ctx = createTestContext('block-1₍1₎')
 
-        expect(resolver.resolve('<parallel>', ctx)).toBeUndefined()
-      }
-    )
+      expect(resolver.resolve('<parallel>', ctx)).toEqual({
+        index: 1,
+        currentItem: 'b',
+        items: ['a', 'b', 'c'],
+      })
+    })
 
-    it.concurrent('should return undefined for unknown parallel property', () => {
+    it.concurrent('should return minimal context object when no distribution', () => {
+      const workflow = createTestWorkflow({
+        'parallel-1': { nodes: ['block-1'] },
+      })
+      const resolver = new ParallelResolver(workflow)
+      const ctx = createTestContext('block-1₍0₎')
+
+      const result = resolver.resolve('<parallel>', ctx)
+      expect(result).toHaveProperty('index', 0)
+      expect(result).toHaveProperty('items')
+    })
+
+    it.concurrent('should throw InvalidFieldError for unknown parallel property', () => {
       const workflow = createTestWorkflow({
         'parallel-1': { nodes: ['block-1'], distribution: ['a'] },
       })
       const resolver = new ParallelResolver(workflow)
       const ctx = createTestContext('block-1₍0₎')
 
-      expect(resolver.resolve('<parallel.unknownProperty>', ctx)).toBeUndefined()
+      expect(() => resolver.resolve('<parallel.unknownProperty>', ctx)).toThrow(InvalidFieldError)
     })
 
     it.concurrent('should return undefined when block is not in any parallel', () => {

apps/sim/executor/variables/resolvers/parallel.ts

@@ -1,5 +1,6 @@
 import { createLogger } from '@sim/logger'
 import { isReference, parseReferencePath, REFERENCE } from '@/executor/constants'
+import { InvalidFieldError } from '@/executor/utils/block-reference'
 import { extractBaseBlockId, extractBranchIndex } from '@/executor/utils/subflow-utils'
 import {
   navigatePath,
@@ -13,6 +14,8 @@ const logger = createLogger('ParallelResolver')
 export class ParallelResolver implements Resolver {
   constructor(private workflow: SerializedWorkflow) {}
 
+  private static KNOWN_PROPERTIES = ['index', 'currentItem', 'items']
+
   canResolve(reference: string): boolean {
     if (!isReference(reference)) {
       return false
@@ -27,12 +30,11 @@ export class ParallelResolver implements Resolver {
 
   resolve(reference: string, context: ResolutionContext): any {
     const parts = parseReferencePath(reference)
-    if (parts.length < 2) {
-      logger.warn('Invalid parallel reference - missing property', { reference })
+    if (parts.length === 0) {
+      logger.warn('Invalid parallel reference', { reference })
       return undefined
     }
 
-    const [_, property, ...pathParts] = parts
     const parallelId = this.findParallelForBlock(context.currentNodeId)
     if (!parallelId) {
       return undefined
@@ -49,11 +51,33 @@ export class ParallelResolver implements Resolver {
       return undefined
     }
 
-    // First try to get items from the parallel scope (resolved at runtime)
-    // This is the same pattern as LoopResolver reading from loopScope.items
     const parallelScope = context.executionContext.parallelExecutions?.get(parallelId)
     const distributionItems = parallelScope?.items ?? this.getDistributionItems(parallelConfig)
 
+    if (parts.length === 1) {
+      const result: Record<string, any> = {
+        index: branchIndex,
+      }
+      if (distributionItems !== undefined) {
+        result.items = distributionItems
+        if (Array.isArray(distributionItems)) {
+          result.currentItem = distributionItems[branchIndex]
+        } else if (typeof distributionItems === 'object' && distributionItems !== null) {
+          const keys = Object.keys(distributionItems)
+          const key = keys[branchIndex]
+          result.currentItem = key !== undefined ? distributionItems[key] : undefined
+        }
+      }
+      return result
+    }
+
+    const [_, property, ...pathParts] = parts
+    if (!ParallelResolver.KNOWN_PROPERTIES.includes(property)) {
+      const isCollection = parallelConfig.parallelType === 'collection'
+      const availableFields = isCollection ? ['index', 'currentItem', 'items'] : ['index']
+      throw new InvalidFieldError('parallel', property, availableFields)
+    }
+
     let value: any
     switch (property) {
       case 'index':
@@ -73,12 +97,8 @@ export class ParallelResolver implements Resolver {
       case 'items':
         value = distributionItems
         break
-      default:
-        logger.warn('Unknown parallel property', { property })
-        return undefined
     }
 
-    // If there are additional path parts, navigate deeper
     if (pathParts.length > 0) {
       return navigatePath(value, pathParts)
     }

apps/sim/executor/variables/resolvers/reference.ts

@@ -27,23 +27,28 @@ export function navigatePath(obj: any, path: string[]): any {
       return undefined
     }
 
-    // Handle array indexing like "items[0]" or just numeric indices
-    const arrayMatch = part.match(/^([^[]+)\[(\d+)\](.*)$/)
+    const arrayMatch = part.match(/^([^[]+)(\[.+)$/)
     if (arrayMatch) {
-      // Handle complex array access like "items[0]"
-      const [, prop, index] = arrayMatch
+      const [, prop, bracketsPart] = arrayMatch
       current = current[prop]
       if (current === undefined || current === null) {
         return undefined
       }
-      const idx = Number.parseInt(index, 10)
-      current = Array.isArray(current) ? current[idx] : undefined
+
+      const indices = bracketsPart.match(/\[(\d+)\]/g)
+      if (indices) {
+        for (const indexMatch of indices) {
+          if (current === null || current === undefined) {
+            return undefined
+          }
+          const idx = Number.parseInt(indexMatch.slice(1, -1), 10)
+          current = Array.isArray(current) ? current[idx] : undefined
+        }
+      }
     } else if (/^\d+$/.test(part)) {
-      // Handle plain numeric index
       const index = Number.parseInt(part, 10)
       current = Array.isArray(current) ? current[index] : undefined
     } else {
-      // Handle regular property access
       current = current[part]
     }
   }

apps/sim/hooks/use-collaborative-workflow.ts

@@ -5,7 +5,7 @@ import { useShallow } from 'zustand/react/shallow'
 import { useSession } from '@/lib/auth/auth-client'
 import { useSocket } from '@/app/workspace/providers/socket-provider'
 import { getBlock } from '@/blocks'
-import { normalizeName } from '@/executor/constants'
+import { normalizeName, RESERVED_BLOCK_NAMES } from '@/executor/constants'
 import { useUndoRedo } from '@/hooks/use-undo-redo'
 import {
   BLOCK_OPERATIONS,
@@ -740,6 +740,16 @@ export function useCollaborativeWorkflow() {
         return { success: false, error: 'Block name cannot be empty' }
       }
 
+      if ((RESERVED_BLOCK_NAMES as readonly string[]).includes(normalizedNewName)) {
+        logger.error(`Cannot rename block to reserved name: "${trimmedName}"`)
+        useNotificationStore.getState().addNotification({
+          level: 'error',
+          message: `"${trimmedName}" is a reserved name and cannot be used`,
+          workflowId: activeWorkflowId || undefined,
+        })
+        return { success: false, error: `"${trimmedName}" is a reserved name` }
+      }
+
       const currentBlocks = useWorkflowStore.getState().blocks
       const conflictingBlock = Object.entries(currentBlocks).find(
         ([blockId, block]) => blockId !== id && normalizeName(block.name) === normalizedNewName

apps/sim/lib/copilot/tools/server/workflow/edit-workflow.ts

@@ -14,7 +14,7 @@ import { validateWorkflowState } from '@/lib/workflows/sanitization/validation'
 import { TriggerUtils } from '@/lib/workflows/triggers/triggers'
 import { getAllBlocks, getBlock } from '@/blocks/registry'
 import type { SubBlockConfig } from '@/blocks/types'
-import { EDGE, normalizeName } from '@/executor/constants'
+import { EDGE, normalizeName, RESERVED_BLOCK_NAMES } from '@/executor/constants'
 import { getUserPermissionConfig } from '@/executor/utils/permission-check'
 import { generateLoopBlocks, generateParallelBlocks } from '@/stores/workflows/workflow/utils'
 import { TRIGGER_RUNTIME_SUBBLOCK_IDS } from '@/triggers/constants'
@@ -63,6 +63,7 @@ type SkippedItemType =
   | 'invalid_subflow_parent'
   | 'nested_subflow_not_allowed'
   | 'duplicate_block_name'
+  | 'reserved_block_name'
   | 'duplicate_trigger'
   | 'duplicate_single_instance_block'
 
@@ -1683,7 +1684,8 @@ function applyOperationsToWorkflowState(
           }
         }
         if (params?.name !== undefined) {
-          if (!normalizeName(params.name)) {
+          const normalizedName = normalizeName(params.name)
+          if (!normalizedName) {
             logSkippedItem(skippedItems, {
               type: 'missing_required_params',
               operationType: 'edit',
@@ -1691,6 +1693,14 @@ function applyOperationsToWorkflowState(
               reason: `Cannot rename to empty name`,
               details: { requestedName: params.name },
             })
+          } else if ((RESERVED_BLOCK_NAMES as readonly string[]).includes(normalizedName)) {
+            logSkippedItem(skippedItems, {
+              type: 'reserved_block_name',
+              operationType: 'edit',
+              blockId: block_id,
+              reason: `Cannot rename to "${params.name}" - this is a reserved name`,
+              details: { requestedName: params.name },
+            })
           } else {
             const conflictingBlock = findBlockWithDuplicateNormalizedName(
               modifiedState.blocks,
@@ -1911,7 +1921,8 @@ function applyOperationsToWorkflowState(
       }
 
       case 'add': {
-        if (!params?.type || !params?.name || !normalizeName(params.name)) {
+        const addNormalizedName = params?.name ? normalizeName(params.name) : ''
+        if (!params?.type || !params?.name || !addNormalizedName) {
           logSkippedItem(skippedItems, {
             type: 'missing_required_params',
             operationType: 'add',
@@ -1922,6 +1933,17 @@ function applyOperationsToWorkflowState(
           break
         }
 
+        if ((RESERVED_BLOCK_NAMES as readonly string[]).includes(addNormalizedName)) {
+          logSkippedItem(skippedItems, {
+            type: 'reserved_block_name',
+            operationType: 'add',
+            blockId: block_id,
+            reason: `Block name "${params.name}" is a reserved name and cannot be used`,
+            details: { requestedName: params.name },
+          })
+          break
+        }
+
         const conflictingBlock = findBlockWithDuplicateNormalizedName(
           modifiedState.blocks,
           params.name,

apps/sim/lib/core/idempotency/cleanup.ts

@@ -1,7 +1,7 @@
 import { db } from '@sim/db'
 import { idempotencyKey } from '@sim/db/schema'
 import { createLogger } from '@sim/logger'
-import { and, eq, lt } from 'drizzle-orm'
+import { and, count, inArray, like, lt, max, min, sql } from 'drizzle-orm'
 
 const logger = createLogger('IdempotencyCleanup')
 
@@ -19,7 +19,8 @@ export interface CleanupOptions {
   batchSize?: number
 
   /**
-   * Specific namespace to clean up, or undefined to clean all namespaces
+   * Specific namespace prefix to clean up (e.g., 'webhook', 'polling')
+   * Keys are prefixed with namespace, so this filters by key prefix
    */
   namespace?: string
 }
@@ -53,13 +54,17 @@ export async function cleanupExpiredIdempotencyKeys(
 
     while (hasMore) {
       try {
+        // Build where condition - filter by cutoff date and optionally by namespace prefix
         const whereCondition = namespace
-          ? and(lt(idempotencyKey.createdAt, cutoffDate), eq(idempotencyKey.namespace, namespace))
+          ? and(
+              lt(idempotencyKey.createdAt, cutoffDate),
+              like(idempotencyKey.key, `${namespace}:%`)
+            )
           : lt(idempotencyKey.createdAt, cutoffDate)
 
-        // First, find IDs to delete with limit
+        // Find keys to delete with limit
         const toDelete = await db
-          .select({ key: idempotencyKey.key, namespace: idempotencyKey.namespace })
+          .select({ key: idempotencyKey.key })
           .from(idempotencyKey)
           .where(whereCondition)
           .limit(batchSize)
@@ -68,14 +73,13 @@ export async function cleanupExpiredIdempotencyKeys(
           break
         }
 
-        // Delete the found records
+        // Delete the found records by key
         const deleteResult = await db
           .delete(idempotencyKey)
           .where(
-            and(
-              ...toDelete.map((item) =>
-                and(eq(idempotencyKey.key, item.key), eq(idempotencyKey.namespace, item.namespace))
-              )
+            inArray(
+              idempotencyKey.key,
+              toDelete.map((item) => item.key)
             )
           )
           .returning({ key: idempotencyKey.key })
@@ -126,6 +130,7 @@ export async function cleanupExpiredIdempotencyKeys(
 
 /**
  * Get statistics about idempotency key usage
+ * Uses SQL aggregations to avoid loading all keys into memory
  */
 export async function getIdempotencyKeyStats(): Promise<{
   totalKeys: number
@@ -134,34 +139,35 @@ export async function getIdempotencyKeyStats(): Promise<{
   newestKey: Date | null
 }> {
   try {
-    const allKeys = await db
+    // Get total count and date range in a single query
+    const [statsResult] = await db
       .select({
-        namespace: idempotencyKey.namespace,
-        createdAt: idempotencyKey.createdAt,
+        totalKeys: count(),
+        oldestKey: min(idempotencyKey.createdAt),
+        newestKey: max(idempotencyKey.createdAt),
       })
       .from(idempotencyKey)
 
-    const totalKeys = allKeys.length
+    // Get counts by namespace prefix using SQL substring
+    // Extracts everything before the first ':' as the namespace
+    const namespaceStats = await db
+      .select({
+        namespace: sql<string>`split_part(${idempotencyKey.key}, ':', 1)`.as('namespace'),
+        count: count(),
+      })
+      .from(idempotencyKey)
+      .groupBy(sql`split_part(${idempotencyKey.key}, ':', 1)`)
+
     const keysByNamespace: Record<string, number> = {}
-    let oldestKey: Date | null = null
-    let newestKey: Date | null = null
-
-    for (const key of allKeys) {
-      keysByNamespace[key.namespace] = (keysByNamespace[key.namespace] || 0) + 1
-
-      if (!oldestKey || key.createdAt < oldestKey) {
-        oldestKey = key.createdAt
-      }
-      if (!newestKey || key.createdAt > newestKey) {
-        newestKey = key.createdAt
-      }
+    for (const row of namespaceStats) {
+      keysByNamespace[row.namespace || 'unknown'] = row.count
     }
 
     return {
-      totalKeys,
+      totalKeys: statsResult?.totalKeys ?? 0,
       keysByNamespace,
-      oldestKey,
-      newestKey,
+      oldestKey: statsResult?.oldestKey ?? null,
+      newestKey: statsResult?.newestKey ?? null,
     }
   } catch (error) {
     logger.error('Failed to get idempotency key stats:', error)

apps/sim/lib/core/idempotency/service.ts

@@ -2,7 +2,7 @@ import { randomUUID } from 'crypto'
 import { db } from '@sim/db'
 import { idempotencyKey } from '@sim/db/schema'
 import { createLogger } from '@sim/logger'
-import { and, eq } from 'drizzle-orm'
+import { eq } from 'drizzle-orm'
 import { getRedisClient } from '@/lib/core/config/redis'
 import { getStorageMethod, type StorageMethod } from '@/lib/core/storage'
 import { extractProviderIdentifierFromBody } from '@/lib/webhooks/provider-utils'
@@ -124,12 +124,7 @@ export class IdempotencyService {
     const existing = await db
       .select({ result: idempotencyKey.result, createdAt: idempotencyKey.createdAt })
       .from(idempotencyKey)
-      .where(
-        and(
-          eq(idempotencyKey.key, normalizedKey),
-          eq(idempotencyKey.namespace, this.config.namespace)
-        )
-      )
+      .where(eq(idempotencyKey.key, normalizedKey))
       .limit(1)
 
     if (existing.length > 0) {
@@ -224,11 +219,12 @@ export class IdempotencyService {
       .insert(idempotencyKey)
       .values({
         key: normalizedKey,
-        namespace: this.config.namespace,
         result: inProgressResult,
         createdAt: new Date(),
       })
-      .onConflictDoNothing()
+      .onConflictDoNothing({
+        target: [idempotencyKey.key],
+      })
       .returning({ key: idempotencyKey.key })
 
     if (insertResult.length > 0) {
@@ -243,12 +239,7 @@ export class IdempotencyService {
     const existing = await db
       .select({ result: idempotencyKey.result })
       .from(idempotencyKey)
-      .where(
-        and(
-          eq(idempotencyKey.key, normalizedKey),
-          eq(idempotencyKey.namespace, this.config.namespace)
-        )
-      )
+      .where(eq(idempotencyKey.key, normalizedKey))
       .limit(1)
 
     const existingResult =
@@ -280,12 +271,7 @@ export class IdempotencyService {
         const existing = await db
           .select({ result: idempotencyKey.result })
           .from(idempotencyKey)
-          .where(
-            and(
-              eq(idempotencyKey.key, normalizedKey),
-              eq(idempotencyKey.namespace, this.config.namespace)
-            )
-          )
+          .where(eq(idempotencyKey.key, normalizedKey))
           .limit(1)
         currentResult = existing.length > 0 ? (existing[0].result as ProcessingResult) : null
       }
@@ -339,12 +325,11 @@ export class IdempotencyService {
       .insert(idempotencyKey)
       .values({
         key: normalizedKey,
-        namespace: this.config.namespace,
         result: result,
         createdAt: new Date(),
       })
       .onConflictDoUpdate({
-        target: [idempotencyKey.key, idempotencyKey.namespace],
+        target: [idempotencyKey.key],
         set: {
           result: result,
           createdAt: new Date(),

apps/sim/lib/execution/isolated-vm-worker.cjs

@@ -130,7 +130,11 @@ async function executeCode(request) {
     await jail.set('environmentVariables', new ivm.ExternalCopy(envVars).copyInto())
 
     for (const [key, value] of Object.entries(contextVariables)) {
-      await jail.set(key, new ivm.ExternalCopy(value).copyInto())
+      if (value === undefined) {
+        await jail.set(key, undefined)
+      } else {
+        await jail.set(key, new ivm.ExternalCopy(value).copyInto())
+      }
     }
 
     const fetchCallback = new ivm.Reference(async (url, optionsJson) => {

apps/sim/stores/workflows/workflow/store.ts

@@ -7,7 +7,7 @@ import { getBlockOutputs } from '@/lib/workflows/blocks/block-outputs'
 import { TriggerUtils } from '@/lib/workflows/triggers/triggers'
 import { getBlock } from '@/blocks'
 import type { SubBlockConfig } from '@/blocks/types'
-import { normalizeName } from '@/executor/constants'
+import { normalizeName, RESERVED_BLOCK_NAMES } from '@/executor/constants'
 import { useWorkflowRegistry } from '@/stores/workflows/registry/store'
 import { useSubBlockStore } from '@/stores/workflows/subblock/store'
 import { filterNewEdges, getUniqueBlockName, mergeSubblockState } from '@/stores/workflows/utils'
@@ -726,6 +726,11 @@ export const useWorkflowStore = create<WorkflowStore>()(
           return { success: false, changedSubblocks: [] }
         }
 
+        if ((RESERVED_BLOCK_NAMES as readonly string[]).includes(normalizedNewName)) {
+          logger.error(`Cannot rename block to reserved name: "${name}"`)
+          return { success: false, changedSubblocks: [] }
+        }
+
         const newState = {
           blocks: {
             ...get().blocks,

apps/sim/tools/function/execute.test.ts

@@ -56,6 +56,7 @@ describe('Function Execute Tool', () => {
         workflowVariables: {},
         blockData: {},
         blockNameMapping: {},
+        blockOutputSchemas: {},
         isCustomTool: false,
         language: 'javascript',
         timeout: 5000,
@@ -83,6 +84,7 @@ describe('Function Execute Tool', () => {
         workflowVariables: {},
         blockData: {},
         blockNameMapping: {},
+        blockOutputSchemas: {},
         isCustomTool: false,
         language: 'javascript',
         workflowId: undefined,
@@ -101,6 +103,7 @@ describe('Function Execute Tool', () => {
         workflowVariables: {},
         blockData: {},
         blockNameMapping: {},
+        blockOutputSchemas: {},
         isCustomTool: false,
         language: 'javascript',
         workflowId: undefined,

apps/sim/tools/function/execute.ts

@@ -53,6 +53,13 @@ export const functionExecuteTool: ToolConfig<CodeExecutionInput, CodeExecutionOu
       description: 'Mapping of block names to block IDs',
       default: {},
     },
+    blockOutputSchemas: {
+      type: 'object',
+      required: false,
+      visibility: 'hidden',
+      description: 'Mapping of block IDs to their output schemas for validation',
+      default: {},
+    },
     workflowVariables: {
       type: 'object',
       required: false,
@@ -81,6 +88,7 @@ export const functionExecuteTool: ToolConfig<CodeExecutionInput, CodeExecutionOu
         workflowVariables: params.workflowVariables || {},
         blockData: params.blockData || {},
         blockNameMapping: params.blockNameMapping || {},
+        blockOutputSchemas: params.blockOutputSchemas || {},
         workflowId: params._context?.workflowId,
         isCustomTool: params.isCustomTool || false,
       }

apps/sim/tools/function/types.ts

@@ -11,6 +11,7 @@ export interface CodeExecutionInput {
   workflowVariables?: Record<string, unknown>
   blockData?: Record<string, unknown>
   blockNameMapping?: Record<string, string>
+  blockOutputSchemas?: Record<string, Record<string, unknown>>
   _context?: {
     workflowId?: string
   }

helm/sim/templates/deployment-app.yaml

@@ -110,12 +110,22 @@ spec:
           {{- end }}
           {{- include "sim.resources" .Values.app | nindent 10 }}
           {{- include "sim.securityContext" .Values.app | nindent 10 }}
-          {{- with .Values.extraVolumeMounts }}
+          {{- if or .Values.extraVolumeMounts .Values.app.extraVolumeMounts }}
           volumeMounts:
+            {{- with .Values.extraVolumeMounts }}
             {{- toYaml . | nindent 12 }}
+            {{- end }}
+            {{- with .Values.app.extraVolumeMounts }}
+            {{- toYaml . | nindent 12 }}
+            {{- end }}
           {{- end }}
-      {{- with .Values.extraVolumes }}
+      {{- if or .Values.extraVolumes .Values.app.extraVolumes }}
       volumes:
+        {{- with .Values.extraVolumes }}
         {{- toYaml . | nindent 8 }}
+        {{- end }}
+        {{- with .Values.app.extraVolumes }}
+        {{- toYaml . | nindent 8 }}
+        {{- end }}
       {{- end }}
 {{- end }}

helm/sim/templates/deployment-ollama.yaml

@@ -92,6 +92,7 @@ spec:
             {{- toYaml .Values.ollama.readinessProbe | nindent 12 }}
           {{- end }}
           {{- include "sim.resources" .Values.ollama | nindent 10 }}
+          {{- if or .Values.ollama.persistence.enabled .Values.extraVolumeMounts .Values.ollama.extraVolumeMounts }}
           volumeMounts:
             {{- if .Values.ollama.persistence.enabled }}
             - name: ollama-data
@@ -100,13 +101,22 @@ spec:
             {{- with .Values.extraVolumeMounts }}
             {{- toYaml . | nindent 12 }}
             {{- end }}
-      {{- if .Values.ollama.persistence.enabled }}
+            {{- with .Values.ollama.extraVolumeMounts }}
+            {{- toYaml . | nindent 12 }}
+            {{- end }}
+          {{- end }}
+      {{- if or .Values.ollama.persistence.enabled .Values.extraVolumes .Values.ollama.extraVolumes }}
       volumes:
+        {{- if .Values.ollama.persistence.enabled }}
         - name: ollama-data
           persistentVolumeClaim:
             claimName: {{ include "sim.fullname" . }}-ollama-data
+        {{- end }}
         {{- with .Values.extraVolumes }}
         {{- toYaml . | nindent 8 }}
         {{- end }}
+        {{- with .Values.ollama.extraVolumes }}
+        {{- toYaml . | nindent 8 }}
+        {{- end }}
       {{- end }}
 {{- end }}

helm/sim/templates/deployment-realtime.yaml

@@ -84,12 +84,22 @@ spec:
           {{- end }}
           {{- include "sim.resources" .Values.realtime | nindent 10 }}
           {{- include "sim.securityContext" .Values.realtime | nindent 10 }}
-          {{- with .Values.extraVolumeMounts }}
+          {{- if or .Values.extraVolumeMounts .Values.realtime.extraVolumeMounts }}
           volumeMounts:
+            {{- with .Values.extraVolumeMounts }}
             {{- toYaml . | nindent 12 }}
+            {{- end }}
+            {{- with .Values.realtime.extraVolumeMounts }}
+            {{- toYaml . | nindent 12 }}
+            {{- end }}
           {{- end }}
-      {{- with .Values.extraVolumes }}
+      {{- if or .Values.extraVolumes .Values.realtime.extraVolumes }}
       volumes:
+        {{- with .Values.extraVolumes }}
         {{- toYaml . | nindent 8 }}
+        {{- end }}
+        {{- with .Values.realtime.extraVolumes }}
+        {{- toYaml . | nindent 8 }}
+        {{- end }}
       {{- end }}
 {{- end }}

helm/sim/values.yaml

@@ -224,6 +224,10 @@ app:
     timeoutSeconds: 5
     failureThreshold: 3
 
+  # Additional volumes for app deployment (e.g., branding assets, custom configs)
+  extraVolumes: []
+  extraVolumeMounts: []
+
 # Realtime socket server configuration
 realtime:
   # Enable/disable the realtime service
@@ -301,6 +305,10 @@ realtime:
     timeoutSeconds: 5
     failureThreshold: 3
 
+  # Additional volumes for realtime deployment
+  extraVolumes: []
+  extraVolumeMounts: []
+
 # Database migrations job configuration
 migrations:
   # Enable/disable migrations job
@@ -539,6 +547,10 @@ ollama:
     timeoutSeconds: 5
     failureThreshold: 3
 
+  # Additional volumes for ollama deployment
+  extraVolumes: []
+  extraVolumeMounts: []
+
 # Ingress configuration
 ingress:
   # Enable/disable ingress

packages/db/migrations/0147_rare_firebrand.sql

@@ -0,0 +1,4 @@
+DROP INDEX "idempotency_key_namespace_unique";--> statement-breakpoint
+DROP INDEX "idempotency_key_namespace_idx";--> statement-breakpoint
+ALTER TABLE "idempotency_key" ADD PRIMARY KEY ("key");--> statement-breakpoint
+ALTER TABLE "idempotency_key" DROP COLUMN "namespace";

packages/db/migrations/meta/_journal.json

@@ -1023,6 +1023,13 @@
       "when": 1768867605608,
       "tag": "0146_cultured_ikaris",
       "breakpoints": true
+    },
+    {
+      "idx": 147,
+      "version": "7",
+      "when": 1769134350805,
+      "tag": "0147_rare_firebrand",
+      "breakpoints": true
     }
   ]
 }

packages/db/schema.ts

@@ -1656,20 +1656,13 @@ export const workflowDeploymentVersion = pgTable(
 export const idempotencyKey = pgTable(
   'idempotency_key',
   {
-    key: text('key').notNull(),
-    namespace: text('namespace').notNull().default('default'),
+    key: text('key').primaryKey(),
     result: json('result').notNull(),
     createdAt: timestamp('created_at').notNull().defaultNow(),
   },
   (table) => ({
-    // Primary key is combination of key and namespace
-    keyNamespacePk: uniqueIndex('idempotency_key_namespace_unique').on(table.key, table.namespace),
-
     // Index for cleanup operations by creation time
     createdAtIdx: index('idempotency_key_created_at_idx').on(table.createdAt),
-
-    // Index for namespace-based queries
-    namespaceIdx: index('idempotency_key_namespace_idx').on(table.namespace),
   })
 )