diff --git a/apps/sim/app/api/copilot/checkpoints/revert/route.ts b/apps/sim/app/api/copilot/checkpoints/revert/route.ts
index e47f2f6d1..f0b635f20 100644
--- a/apps/sim/app/api/copilot/checkpoints/revert/route.ts
+++ b/apps/sim/app/api/copilot/checkpoints/revert/route.ts
@@ -10,9 +10,9 @@ import {
   createRequestTracker,
   createUnauthorizedResponse,
 } from '@/lib/copilot/request-helpers'
-import { validateUUID } from '@/lib/core/security/input-validation'
 import { getBaseUrl } from '@/lib/core/utils/urls'
 import { createLogger } from '@/lib/logs/console/logger'
+import { isUuidV4 } from '@/executor/constants'
 
 const logger = createLogger('CheckpointRevertAPI')
 
@@ -87,9 +87,8 @@ export async function POST(request: NextRequest) {
       isDeployed: cleanedState.isDeployed,
     })
 
-    const workflowIdValidation = validateUUID(checkpoint.workflowId, 'workflowId')
-    if (!workflowIdValidation.isValid) {
-      logger.error(`[${tracker.requestId}] Invalid workflow ID: ${workflowIdValidation.error}`)
+    if (!isUuidV4(checkpoint.workflowId)) {
+      logger.error(`[${tracker.requestId}] Invalid workflow ID format`)
       return NextResponse.json({ error: 'Invalid workflow ID format' }, { status: 400 })
     }
 
diff --git a/apps/sim/app/api/copilot/execute-tool/route.ts b/apps/sim/app/api/copilot/execute-tool/route.ts
index c83685152..e5cb66095 100644
--- a/apps/sim/app/api/copilot/execute-tool/route.ts
+++ b/apps/sim/app/api/copilot/execute-tool/route.ts
@@ -14,6 +14,8 @@ import { generateRequestId } from '@/lib/core/utils/request'
 import { getEffectiveDecryptedEnv } from '@/lib/environment/utils'
 import { createLogger } from '@/lib/logs/console/logger'
 import { refreshTokenIfNeeded } from '@/app/api/auth/oauth/utils'
+import { REFERENCE } from '@/executor/constants'
+import { createEnvVarPattern } from '@/executor/utils/reference-validation'
 import { executeTool } from '@/tools'
 import { getTool } from '@/tools/utils'
 
@@ -33,14 +35,18 @@ const ExecuteToolSchema = z.object({
 function resolveEnvVarReferences(value: any, envVars: Record<string, string>): any {
   if (typeof value === 'string') {
     // Check for exact match: entire string is "{{VAR_NAME}}"
-    const exactMatch = /^\{\{([^}]+)\}\}$/.exec(value)
+    const exactMatchPattern = new RegExp(
+      `^\\${REFERENCE.ENV_VAR_START}([^}]+)\\${REFERENCE.ENV_VAR_END}$`
+    )
+    const exactMatch = exactMatchPattern.exec(value)
     if (exactMatch) {
       const envVarName = exactMatch[1].trim()
       return envVars[envVarName] ?? value
     }
 
     // Check for embedded references: "prefix {{VAR}} suffix"
-    return value.replace(/\{\{([^}]+)\}\}/g, (match, varName) => {
+    const envVarPattern = createEnvVarPattern()
+    return value.replace(envVarPattern, (match, varName) => {
       const trimmedName = varName.trim()
       return envVars[trimmedName] ?? match
     })
diff --git a/apps/sim/app/api/files/authorization.ts b/apps/sim/app/api/files/authorization.ts
index 6083a92c7..65b3381a1 100644
--- a/apps/sim/app/api/files/authorization.ts
+++ b/apps/sim/app/api/files/authorization.ts
@@ -14,6 +14,7 @@ import type { StorageConfig } from '@/lib/uploads/core/storage-client'
 import { getFileMetadataByKey } from '@/lib/uploads/server/metadata'
 import { inferContextFromKey } from '@/lib/uploads/utils/file-utils'
 import { getUserEntityPermissions } from '@/lib/workspaces/permissions/utils'
+import { isUuid } from '@/executor/constants'
 
 const logger = createLogger('FileAuthorization')
 
@@ -85,9 +86,7 @@ function extractWorkspaceIdFromKey(key: string): string | null {
   const parts = key.split('/')
   const workspaceId = parts[0]
 
-  // Validate UUID format
-  const UUID_PATTERN = /^[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}$/i
-  if (workspaceId && UUID_PATTERN.test(workspaceId)) {
+  if (workspaceId && isUuid(workspaceId)) {
     return workspaceId
   }
 
diff --git a/apps/sim/app/api/files/upload/route.ts b/apps/sim/app/api/files/upload/route.ts
index 89d911e89..c23f46ec8 100644
--- a/apps/sim/app/api/files/upload/route.ts
+++ b/apps/sim/app/api/files/upload/route.ts
@@ -1,5 +1,6 @@
 import { type NextRequest, NextResponse } from 'next/server'
 import { createLogger } from '@/lib/logs/console/logger'
+import { sanitizeFileName } from '@/executor/constants'
 import '@/lib/uploads/core/setup.server'
 import { getSession } from '@/lib/auth'
 import type { StorageContext } from '@/lib/uploads/config'
@@ -154,7 +155,7 @@ export async function POST(request: NextRequest) {
         logger.info(`Uploading knowledge-base file: ${originalName}`)
 
         const timestamp = Date.now()
-        const safeFileName = originalName.replace(/\s+/g, '-')
+        const safeFileName = sanitizeFileName(originalName)
         const storageKey = `kb/${timestamp}-${safeFileName}`
 
         const metadata: Record<string, string> = {
@@ -267,9 +268,8 @@ export async function POST(request: NextRequest) {
 
         logger.info(`Uploading ${context} file: ${originalName}`)
 
-        // Generate storage key with context prefix and timestamp to ensure uniqueness
         const timestamp = Date.now()
-        const safeFileName = originalName.replace(/\s+/g, '-')
+        const safeFileName = sanitizeFileName(originalName)
         const storageKey = `${context}/${timestamp}-${safeFileName}`
 
         const metadata: Record<string, string> = {
diff --git a/apps/sim/app/api/function/execute/route.ts b/apps/sim/app/api/function/execute/route.ts
index b09fde257..ce42d5e67 100644
--- a/apps/sim/app/api/function/execute/route.ts
+++ b/apps/sim/app/api/function/execute/route.ts
@@ -5,6 +5,7 @@ import { executeInE2B } from '@/lib/execution/e2b'
 import { executeInIsolatedVM } from '@/lib/execution/isolated-vm'
 import { CodeLanguage, DEFAULT_CODE_LANGUAGE, isValidCodeLanguage } from '@/lib/execution/languages'
 import { createLogger } from '@/lib/logs/console/logger'
+import { escapeRegExp, normalizeName, REFERENCE } from '@/executor/constants'
 import {
   createEnvVarPattern,
   createWorkflowVariablePattern,
@@ -405,7 +406,7 @@ function resolveWorkflowVariables(
 
     // Find the variable by name (workflowVariables is indexed by ID, values are variable objects)
     const foundVariable = Object.entries(workflowVariables).find(
-      ([_, variable]) => (variable.name || '').replace(/\s+/g, '') === variableName
+      ([_, variable]) => normalizeName(variable.name || '') === variableName
     )
 
     let variableValue: unknown = ''
@@ -513,31 +514,26 @@ function resolveTagVariables(
 ): string {
   let resolvedCode = code
 
-  const tagMatches = resolvedCode.match(/<([a-zA-Z_][a-zA-Z0-9_.]*[a-zA-Z0-9_])>/g) || []
+  const tagPattern = new RegExp(
+    `${REFERENCE.START}([a-zA-Z_][a-zA-Z0-9_${REFERENCE.PATH_DELIMITER}]*[a-zA-Z0-9_])${REFERENCE.END}`,
+    'g'
+  )
+  const tagMatches = resolvedCode.match(tagPattern) || []
 
   for (const match of tagMatches) {
-    const tagName = match.slice(1, -1).trim()
+    const tagName = match.slice(REFERENCE.START.length, -REFERENCE.END.length).trim()
 
     // Handle nested paths like "getrecord.response.data" or "function1.response.result"
     // First try params, then blockData directly, then try with block name mapping
     let tagValue = getNestedValue(params, tagName) || getNestedValue(blockData, tagName) || ''
 
     // If not found and the path starts with a block name, try mapping the block name to ID
-    if (!tagValue && tagName.includes('.')) {
-      const pathParts = tagName.split('.')
+    if (!tagValue && tagName.includes(REFERENCE.PATH_DELIMITER)) {
+      const pathParts = tagName.split(REFERENCE.PATH_DELIMITER)
       const normalizedBlockName = pathParts[0] // This should already be normalized like "function1"
 
-      // Find the block ID by looking for a block name that normalizes to this value
-      let blockId = null
-
-      for (const [blockName, id] of Object.entries(blockNameMapping)) {
-        // Apply the same normalization logic as the UI: remove spaces and lowercase
-        const normalizedName = blockName.replace(/\s+/g, '').toLowerCase()
-        if (normalizedName === normalizedBlockName) {
-          blockId = id
-          break
-        }
-      }
+      // Direct lookup using normalized block name
+      const blockId = blockNameMapping[normalizedBlockName] ?? null
 
       if (blockId) {
         const remainingPath = pathParts.slice(1).join('.')
@@ -617,13 +613,6 @@ function getNestedValue(obj: any, path: string): any {
   }, obj)
 }
 
-/**
- * Escape special regex characters in a string
- */
-function escapeRegExp(string: string): string {
-  return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
-}
-
 /**
  * Remove one trailing newline from stdout
  * This handles the common case where print() or console.log() adds a trailing \n
diff --git a/apps/sim/app/api/mcp/servers/test-connection/route.ts b/apps/sim/app/api/mcp/servers/test-connection/route.ts
index 840fb4aae..1c4add215 100644
--- a/apps/sim/app/api/mcp/servers/test-connection/route.ts
+++ b/apps/sim/app/api/mcp/servers/test-connection/route.ts
@@ -6,6 +6,8 @@ import { getParsedBody, withMcpAuth } from '@/lib/mcp/middleware'
 import type { McpServerConfig, McpTransport } from '@/lib/mcp/types'
 import { validateMcpServerUrl } from '@/lib/mcp/url-validator'
 import { createMcpErrorResponse, createMcpSuccessResponse } from '@/lib/mcp/utils'
+import { REFERENCE } from '@/executor/constants'
+import { createEnvVarPattern } from '@/executor/utils/reference-validation'
 
 const logger = createLogger('McpServerTestAPI')
 
@@ -23,12 +25,13 @@ function isUrlBasedTransport(transport: McpTransport): boolean {
  * Resolve environment variables in strings
  */
 function resolveEnvVars(value: string, envVars: Record<string, string>): string {
-  const envMatches = value.match(/\{\{([^}]+)\}\}/g)
+  const envVarPattern = createEnvVarPattern()
+  const envMatches = value.match(envVarPattern)
   if (!envMatches) return value
 
   let resolvedValue = value
   for (const match of envMatches) {
-    const envKey = match.slice(2, -2).trim()
+    const envKey = match.slice(REFERENCE.ENV_VAR_START.length, -REFERENCE.ENV_VAR_END.length).trim()
     const envValue = envVars[envKey]
 
     if (envValue === undefined) {
diff --git a/apps/sim/app/api/tools/google_calendar/calendars/route.ts b/apps/sim/app/api/tools/google_calendar/calendars/route.ts
index 7fc17db6e..77b6291bf 100644
--- a/apps/sim/app/api/tools/google_calendar/calendars/route.ts
+++ b/apps/sim/app/api/tools/google_calendar/calendars/route.ts
@@ -1,9 +1,9 @@
 import { type NextRequest, NextResponse } from 'next/server'
 import { authorizeCredentialUse } from '@/lib/auth/credential-access'
-import { validateUUID } from '@/lib/core/security/input-validation'
 import { generateRequestId } from '@/lib/core/utils/request'
 import { createLogger } from '@/lib/logs/console/logger'
 import { refreshAccessTokenIfNeeded } from '@/app/api/auth/oauth/utils'
+import { isUuidV4 } from '@/executor/constants'
 export const dynamic = 'force-dynamic'
 
 const logger = createLogger('GoogleCalendarAPI')
@@ -35,18 +35,14 @@ export async function GET(request: NextRequest) {
       return NextResponse.json({ error: 'Credential ID is required' }, { status: 400 })
     }
 
-    const credentialValidation = validateUUID(credentialId, 'credentialId')
-    if (!credentialValidation.isValid) {
+    if (!isUuidV4(credentialId)) {
       logger.warn(`[${requestId}] Invalid credentialId format`, { credentialId })
-      return NextResponse.json({ error: credentialValidation.error }, { status: 400 })
+      return NextResponse.json({ error: 'Invalid credential ID format' }, { status: 400 })
     }
 
-    if (workflowId) {
-      const workflowValidation = validateUUID(workflowId, 'workflowId')
-      if (!workflowValidation.isValid) {
-        logger.warn(`[${requestId}] Invalid workflowId format`, { workflowId })
-        return NextResponse.json({ error: workflowValidation.error }, { status: 400 })
-      }
+    if (workflowId && !isUuidV4(workflowId)) {
+      logger.warn(`[${requestId}] Invalid workflowId format`, { workflowId })
+      return NextResponse.json({ error: 'Invalid workflow ID format' }, { status: 400 })
     }
     const authz = await authorizeCredentialUse(request, { credentialId, workflowId })
     if (!authz.ok || !authz.credentialOwnerUserId) {
diff --git a/apps/sim/app/api/workflows/[id]/execute/route.ts b/apps/sim/app/api/workflows/[id]/execute/route.ts
index acf3015ab..df35fc3ca 100644
--- a/apps/sim/app/api/workflows/[id]/execute/route.ts
+++ b/apps/sim/app/api/workflows/[id]/execute/route.ts
@@ -22,6 +22,7 @@ import {
 import { createStreamingResponse } from '@/lib/workflows/streaming/streaming'
 import { createHttpResponseFromBlock, workflowHasResponseBlock } from '@/lib/workflows/utils'
 import type { WorkflowExecutionPayload } from '@/background/workflow-execution'
+import { normalizeName } from '@/executor/constants'
 import { type ExecutionMetadata, ExecutionSnapshot } from '@/executor/execution/snapshot'
 import type { StreamingExecution } from '@/executor/types'
 import { Serializer } from '@/serializer'
@@ -86,10 +87,9 @@ function resolveOutputIds(
     const blockName = outputId.substring(0, dotIndex)
     const path = outputId.substring(dotIndex + 1)
 
-    const normalizedBlockName = blockName.toLowerCase().replace(/\s+/g, '')
+    const normalizedBlockName = normalizeName(blockName)
     const block = Object.values(blocks).find((b: any) => {
-      const normalized = (b.name || '').toLowerCase().replace(/\s+/g, '')
-      return normalized === normalizedBlockName
+      return normalizeName(b.name || '') === normalizedBlockName
     })
 
     if (!block) {
diff --git a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/deploy/components/deploy-modal/deploy-modal.tsx b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/deploy/components/deploy-modal/deploy-modal.tsx
index 84b3996fb..7ea3acfd5 100644
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/deploy/components/deploy-modal/deploy-modal.tsx
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/deploy/components/deploy-modal/deploy-modal.tsx
@@ -18,6 +18,7 @@ import { getEnv } from '@/lib/core/config/env'
 import { createLogger } from '@/lib/logs/console/logger'
 import { getInputFormatExample as getInputFormatExampleUtil } from '@/lib/workflows/operations/deployment-utils'
 import type { WorkflowDeploymentVersionResponse } from '@/lib/workflows/persistence/utils'
+import { startsWithUuid } from '@/executor/constants'
 import { useWorkflowRegistry } from '@/stores/workflows/registry/store'
 import { useWorkflowStore } from '@/stores/workflows/workflow/store'
 import type { WorkflowState } from '@/stores/workflows/workflow/types'
@@ -289,10 +290,9 @@ export function DeployModal({
     if (!open || selectedStreamingOutputs.length === 0) return
 
     const blocks = Object.values(useWorkflowStore.getState().blocks)
-    const UUID_REGEX = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}/i
 
     const validOutputs = selectedStreamingOutputs.filter((outputId) => {
-      if (UUID_REGEX.test(outputId)) {
+      if (startsWithUuid(outputId)) {
         const underscoreIndex = outputId.indexOf('_')
         if (underscoreIndex === -1) return false
 
diff --git a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/hooks/use-subflow-editor.ts b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/hooks/use-subflow-editor.ts
index 64503e03e..caaa59749 100644
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/hooks/use-subflow-editor.ts
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/hooks/use-subflow-editor.ts
@@ -7,9 +7,9 @@ import {
 } from '@/lib/workflows/sanitization/references'
 import { checkTagTrigger } from '@/app/workspace/[workspaceId]/w/[workflowId]/components/panel/components/editor/components/sub-block/components/tag-dropdown/tag-dropdown'
 import { useAccessibleReferencePrefixes } from '@/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-accessible-reference-prefixes'
+import { normalizeName, REFERENCE } from '@/executor/constants'
 import { createEnvVarPattern, createReferencePattern } from '@/executor/utils/reference-validation'
 import { useCollaborativeWorkflow } from '@/hooks/use-collaborative-workflow'
-import { normalizeName } from '@/stores/workflows/utils'
 import { useWorkflowStore } from '@/stores/workflows/workflow/store'
 import type { BlockState } from '@/stores/workflows/workflow/types'
 
@@ -89,7 +89,7 @@ export function useSubflowEditor(currentBlock: BlockState | null, currentBlockId
    */
   const shouldHighlightReference = useCallback(
     (part: string): boolean => {
-      if (!part.startsWith('<') || !part.endsWith('>')) {
+      if (!part.startsWith(REFERENCE.START) || !part.endsWith(REFERENCE.END)) {
         return false
       }
 
@@ -108,8 +108,8 @@ export function useSubflowEditor(currentBlock: BlockState | null, currentBlockId
         return true
       }
 
-      const inner = reference.slice(1, -1)
-      const [prefix] = inner.split('.')
+      const inner = reference.slice(REFERENCE.START.length, -REFERENCE.END.length)
+      const [prefix] = inner.split(REFERENCE.PATH_DELIMITER)
       const normalizedPrefix = normalizeName(prefix)
 
       if (SYSTEM_REFERENCE_PREFIXES.has(normalizedPrefix)) {
diff --git a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-accessible-reference-prefixes.ts b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-accessible-reference-prefixes.ts
index b589972e1..55aa01c21 100644
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-accessible-reference-prefixes.ts
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-accessible-reference-prefixes.ts
@@ -2,7 +2,7 @@ import { useMemo } from 'react'
 import { useShallow } from 'zustand/react/shallow'
 import { BlockPathCalculator } from '@/lib/workflows/blocks/block-path-calculator'
 import { SYSTEM_REFERENCE_PREFIXES } from '@/lib/workflows/sanitization/references'
-import { normalizeName } from '@/stores/workflows/utils'
+import { normalizeName } from '@/executor/constants'
 import { useWorkflowStore } from '@/stores/workflows/workflow/store'
 import type { Loop, Parallel } from '@/stores/workflows/workflow/types'
 
diff --git a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-block-connections.ts b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-block-connections.ts
index 5671a4caa..95c78a369 100644
--- a/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-block-connections.ts
+++ b/apps/sim/app/workspace/[workspaceId]/w/[workflowId]/hooks/use-block-connections.ts
@@ -3,6 +3,7 @@ import { createLogger } from '@/lib/logs/console/logger'
 import { getBlockOutputs } from '@/lib/workflows/blocks/block-outputs'
 import { BlockPathCalculator } from '@/lib/workflows/blocks/block-path-calculator'
 import { TriggerUtils } from '@/lib/workflows/triggers/triggers'
+import { REFERENCE } from '@/executor/constants'
 import { useWorkflowRegistry } from '@/stores/workflows/registry/store'
 import { useSubBlockStore } from '@/stores/workflows/subblock/store'
 import { useWorkflowStore } from '@/stores/workflows/workflow/store'
@@ -44,7 +45,7 @@ function parseResponseFormatSafely(responseFormatValue: any, blockId: string): a
   if (typeof responseFormatValue === 'string') {
     const trimmedValue = responseFormatValue.trim()
 
-    if (trimmedValue.startsWith('<') && trimmedValue.includes('>')) {
+    if (trimmedValue.startsWith(REFERENCE.START) && trimmedValue.includes(REFERENCE.END)) {
       return trimmedValue
     }
 
diff --git a/apps/sim/app/workspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/environment/environment.tsx b/apps/sim/app/workspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/environment/environment.tsx
index a3a535e73..e0497d27e 100644
--- a/apps/sim/app/workspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/environment/environment.tsx
+++ b/apps/sim/app/workspace/[workspaceId]/w/components/sidebar/components/settings-modal/components/environment/environment.tsx
@@ -16,6 +16,7 @@ import {
 import { Trash } from '@/components/emcn/icons/trash'
 import { Input, Skeleton } from '@/components/ui'
 import { createLogger } from '@/lib/logs/console/logger'
+import { isValidEnvVarName } from '@/executor/constants'
 import {
   usePersonalEnvironment,
   useRemoveWorkspaceEnvironment,
@@ -28,7 +29,6 @@ import {
 const logger = createLogger('EnvironmentVariables')
 
 const GRID_COLS = 'grid grid-cols-[minmax(0,1fr)_8px_minmax(0,1fr)_auto] items-center'
-const ENV_VAR_PATTERN = /^[A-Za-z_][A-Za-z0-9_]*$/
 const PRIMARY_BUTTON_STYLES =
   '!bg-[var(--brand-tertiary-2)] !text-[var(--text-inverse)] hover:!bg-[var(--brand-tertiary-2)]/90'
 
@@ -59,7 +59,7 @@ interface UIEnvironmentVariable {
 function validateEnvVarKey(key: string): string | undefined {
   if (!key) return undefined
   if (key.includes(' ')) return 'Spaces are not allowed'
-  if (!ENV_VAR_PATTERN.test(key)) return 'Only letters, numbers, and underscores allowed'
+  if (!isValidEnvVarName(key)) return 'Only letters, numbers, and underscores allowed'
   return undefined
 }
 
@@ -377,7 +377,7 @@ export function EnvironmentVariables({ registerBeforeLeaveHandler }: Environment
     if (equalIndex === -1 || equalIndex === 0) return null
 
     const potentialKey = withoutExport.substring(0, equalIndex).trim()
-    if (!ENV_VAR_PATTERN.test(potentialKey)) return null
+    if (!isValidEnvVarName(potentialKey)) return null
 
     let value = withoutExport.substring(equalIndex + 1)
 
diff --git a/apps/sim/background/schedule-execution.ts b/apps/sim/background/schedule-execution.ts
index 34253bb7b..f0e778f79 100644
--- a/apps/sim/background/schedule-execution.ts
+++ b/apps/sim/background/schedule-execution.ts
@@ -22,8 +22,10 @@ import {
   getScheduleTimeValues,
   getSubBlockValue,
 } from '@/lib/workflows/schedules/utils'
+import { REFERENCE } from '@/executor/constants'
 import { type ExecutionMetadata, ExecutionSnapshot } from '@/executor/execution/snapshot'
 import type { ExecutionResult } from '@/executor/types'
+import { createEnvVarPattern } from '@/executor/utils/reference-validation'
 import { mergeSubblockState } from '@/stores/workflows/server-utils'
 
 const logger = createLogger('TriggerScheduleExecution')
@@ -128,17 +130,25 @@ async function ensureBlockVariablesResolvable(
       await Promise.all(
         Object.values(subBlocks).map(async (subBlock) => {
           const value = subBlock.value
-          if (typeof value !== 'string' || !value.includes('{{') || !value.includes('}}')) {
+          if (
+            typeof value !== 'string' ||
+            !value.includes(REFERENCE.ENV_VAR_START) ||
+            !value.includes(REFERENCE.ENV_VAR_END)
+          ) {
             return
           }
 
-          const matches = value.match(/{{([^}]+)}}/g)
+          const envVarPattern = createEnvVarPattern()
+          const matches = value.match(envVarPattern)
           if (!matches) {
             return
           }
 
           for (const match of matches) {
-            const varName = match.slice(2, -2)
+            const varName = match.slice(
+              REFERENCE.ENV_VAR_START.length,
+              -REFERENCE.ENV_VAR_END.length
+            )
             const encryptedValue = variables[varName]
             if (!encryptedValue) {
               throw new Error(`Environment variable "${varName}" was not found`)
diff --git a/apps/sim/executor/constants.ts b/apps/sim/executor/constants.ts
index 99d0b5b16..ecf9e4ddf 100644
--- a/apps/sim/executor/constants.ts
+++ b/apps/sim/executor/constants.ts
@@ -165,6 +165,10 @@ export const AGENT = {
   CUSTOM_TOOL_PREFIX: 'custom_',
 } as const
 
+export const MCP = {
+  TOOL_PREFIX: 'mcp-',
+} as const
+
 export const MEMORY = {
   DEFAULT_SLIDING_WINDOW_SIZE: 10,
   DEFAULT_SLIDING_WINDOW_TOKENS: 4000,
@@ -338,3 +342,60 @@ export function parseReferencePath(reference: string): string[] {
   const content = extractReferenceContent(reference)
   return content.split(REFERENCE.PATH_DELIMITER)
 }
+
+export const PATTERNS = {
+  UUID: /^[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}$/i,
+  UUID_V4: /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i,
+  UUID_PREFIX: /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}/i,
+  ENV_VAR_NAME: /^[A-Za-z_][A-Za-z0-9_]*$/,
+} as const
+
+export function isUuid(value: string): boolean {
+  return PATTERNS.UUID.test(value)
+}
+
+export function isUuidV4(value: string): boolean {
+  return PATTERNS.UUID_V4.test(value)
+}
+
+export function startsWithUuid(value: string): boolean {
+  return PATTERNS.UUID_PREFIX.test(value)
+}
+
+export function isValidEnvVarName(name: string): boolean {
+  return PATTERNS.ENV_VAR_NAME.test(name)
+}
+
+export function sanitizeFileName(fileName: string): string {
+  return fileName.replace(/\s+/g, '-').replace(/[^a-zA-Z0-9.-]/g, '_')
+}
+
+export function isCustomTool(toolId: string): boolean {
+  return toolId.startsWith(AGENT.CUSTOM_TOOL_PREFIX)
+}
+
+export function isMcpTool(toolId: string): boolean {
+  return toolId.startsWith(MCP.TOOL_PREFIX)
+}
+
+export function stripCustomToolPrefix(name: string): string {
+  return name.startsWith(AGENT.CUSTOM_TOOL_PREFIX)
+    ? name.slice(AGENT.CUSTOM_TOOL_PREFIX.length)
+    : name
+}
+
+export function stripMcpToolPrefix(name: string): string {
+  return name.startsWith(MCP.TOOL_PREFIX) ? name.slice(MCP.TOOL_PREFIX.length) : name
+}
+
+export function escapeRegExp(value: string): string {
+  return value.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
+}
+
+/**
+ * Normalizes a name for comparison by converting to lowercase and removing spaces.
+ * Used for both block names and variable names to ensure consistent matching.
+ */
+export function normalizeName(name: string): string {
+  return name.toLowerCase().replace(/\s+/g, '')
+}
diff --git a/apps/sim/executor/handlers/agent/agent-handler.test.ts b/apps/sim/executor/handlers/agent/agent-handler.test.ts
index e6e5e95e9..d0e259533 100644
--- a/apps/sim/executor/handlers/agent/agent-handler.test.ts
+++ b/apps/sim/executor/handlers/agent/agent-handler.test.ts
@@ -1,6 +1,6 @@
 import { afterEach, beforeEach, describe, expect, it, type Mock, vi } from 'vitest'
 import { getAllBlocks } from '@/blocks'
-import { BlockType } from '@/executor/constants'
+import { BlockType, isMcpTool } from '@/executor/constants'
 import { AgentBlockHandler } from '@/executor/handlers/agent/agent-handler'
 import type { ExecutionContext, StreamingExecution } from '@/executor/types'
 import { executeProviderRequest } from '@/providers'
@@ -1384,7 +1384,7 @@ describe('AgentBlockHandler', () => {
 
     it('should handle MCP tools in agent execution', async () => {
       mockExecuteTool.mockImplementation((toolId, params, skipProxy, skipPostProcess, context) => {
-        if (toolId.startsWith('mcp-')) {
+        if (isMcpTool(toolId)) {
           return Promise.resolve({
             success: true,
             output: {
@@ -1660,7 +1660,7 @@ describe('AgentBlockHandler', () => {
       let capturedContext: any
       mockExecuteTool.mockImplementation((toolId, params, skipProxy, skipPostProcess, context) => {
         capturedContext = context
-        if (toolId.startsWith('mcp-')) {
+        if (isMcpTool(toolId)) {
           return Promise.resolve({
             success: true,
             output: { content: [{ type: 'text', text: 'Success' }] },
diff --git a/apps/sim/executor/handlers/agent/agent-handler.ts b/apps/sim/executor/handlers/agent/agent-handler.ts
index 292a154f0..4f70ebdf0 100644
--- a/apps/sim/executor/handlers/agent/agent-handler.ts
+++ b/apps/sim/executor/handlers/agent/agent-handler.ts
@@ -6,7 +6,14 @@ import { createMcpToolId } from '@/lib/mcp/utils'
 import { refreshTokenIfNeeded } from '@/app/api/auth/oauth/utils'
 import { getAllBlocks } from '@/blocks'
 import type { BlockOutput } from '@/blocks/types'
-import { AGENT, BlockType, DEFAULTS, HTTP } from '@/executor/constants'
+import {
+  AGENT,
+  BlockType,
+  DEFAULTS,
+  HTTP,
+  REFERENCE,
+  stripCustomToolPrefix,
+} from '@/executor/constants'
 import { memoryService } from '@/executor/handlers/agent/memory'
 import type {
   AgentInputs,
@@ -105,7 +112,7 @@ export class AgentBlockHandler implements BlockHandler {
     if (typeof responseFormat === 'string') {
       const trimmedValue = responseFormat.trim()
 
-      if (trimmedValue.startsWith('<') && trimmedValue.includes('>')) {
+      if (trimmedValue.startsWith(REFERENCE.START) && trimmedValue.includes(REFERENCE.END)) {
         return undefined
       }
 
@@ -1337,7 +1344,7 @@ export class AgentBlockHandler implements BlockHandler {
   }
 
   private formatToolCall(tc: any) {
-    const toolName = this.stripCustomToolPrefix(tc.name)
+    const toolName = stripCustomToolPrefix(tc.name)
 
     return {
       ...tc,
@@ -1349,10 +1356,4 @@ export class AgentBlockHandler implements BlockHandler {
       result: tc.result || tc.output,
     }
   }
-
-  private stripCustomToolPrefix(name: string): string {
-    return name.startsWith(AGENT.CUSTOM_TOOL_PREFIX)
-      ? name.replace(AGENT.CUSTOM_TOOL_PREFIX, '')
-      : name
-  }
 }
diff --git a/apps/sim/executor/handlers/condition/condition-handler.test.ts b/apps/sim/executor/handlers/condition/condition-handler.test.ts
index abc415948..b0e1c103a 100644
--- a/apps/sim/executor/handlers/condition/condition-handler.test.ts
+++ b/apps/sim/executor/handlers/condition/condition-handler.test.ts
@@ -24,7 +24,7 @@ vi.mock('@/tools', () => ({
 vi.mock('@/executor/utils/block-data', () => ({
   collectBlockData: vi.fn(() => ({
     blockData: { 'source-block-1': { value: 10, text: 'hello' } },
-    blockNameMapping: { 'Source Block': 'source-block-1' },
+    blockNameMapping: { sourceblock: 'source-block-1' },
   })),
 }))
 
@@ -200,7 +200,7 @@ describe('ConditionBlockHandler', () => {
         envVars: mockContext.environmentVariables,
         workflowVariables: mockContext.workflowVariables,
         blockData: { 'source-block-1': { value: 10, text: 'hello' } },
-        blockNameMapping: { 'Source Block': 'source-block-1' },
+        blockNameMapping: { sourceblock: 'source-block-1' },
         _context: {
           workflowId: 'test-workflow-id',
           workspaceId: 'test-workspace-id',
diff --git a/apps/sim/executor/handlers/generic/generic-handler.ts b/apps/sim/executor/handlers/generic/generic-handler.ts
index c875ab140..4d23721e3 100644
--- a/apps/sim/executor/handlers/generic/generic-handler.ts
+++ b/apps/sim/executor/handlers/generic/generic-handler.ts
@@ -1,5 +1,6 @@
 import { createLogger } from '@/lib/logs/console/logger'
 import { getBlock } from '@/blocks/index'
+import { isMcpTool } from '@/executor/constants'
 import type { BlockHandler, ExecutionContext } from '@/executor/types'
 import type { SerializedBlock } from '@/serializer/types'
 import { executeTool } from '@/tools'
@@ -17,10 +18,10 @@ export class GenericBlockHandler implements BlockHandler {
     block: SerializedBlock,
     inputs: Record<string, any>
   ): Promise<any> {
-    const isMcpTool = block.config.tool?.startsWith('mcp-')
+    const isMcp = block.config.tool ? isMcpTool(block.config.tool) : false
     let tool = null
 
-    if (!isMcpTool) {
+    if (!isMcp) {
       tool = getTool(block.config.tool)
       if (!tool) {
         throw new Error(`Tool not found: ${block.config.tool}`)
diff --git a/apps/sim/executor/handlers/human-in-the-loop/human-in-the-loop-handler.ts b/apps/sim/executor/handlers/human-in-the-loop/human-in-the-loop-handler.ts
index b94a0a203..5764f59fb 100644
--- a/apps/sim/executor/handlers/human-in-the-loop/human-in-the-loop-handler.ts
+++ b/apps/sim/executor/handlers/human-in-the-loop/human-in-the-loop-handler.ts
@@ -7,7 +7,9 @@ import {
   buildResumeUiUrl,
   type FieldType,
   HTTP,
+  normalizeName,
   PAUSE_RESUME,
+  REFERENCE,
 } from '@/executor/constants'
 import {
   generatePauseContextId,
@@ -16,7 +18,6 @@ import {
 import type { BlockHandler, ExecutionContext, PauseMetadata } from '@/executor/types'
 import { collectBlockData } from '@/executor/utils/block-data'
 import type { SerializedBlock } from '@/serializer/types'
-import { normalizeName } from '@/stores/workflows/utils'
 import { executeTool } from '@/tools'
 
 const logger = createLogger('HumanInTheLoopBlockHandler')
@@ -477,7 +478,11 @@ export class HumanInTheLoopBlockHandler implements BlockHandler {
   }
 
   private isVariableReference(value: any): boolean {
-    return typeof value === 'string' && value.trim().startsWith('<') && value.trim().includes('>')
+    return (
+      typeof value === 'string' &&
+      value.trim().startsWith(REFERENCE.START) &&
+      value.trim().includes(REFERENCE.END)
+    )
   }
 
   private parseObjectStrings(data: any): any {
@@ -590,7 +595,6 @@ export class HumanInTheLoopBlockHandler implements BlockHandler {
     blockDataWithPause[pauseBlockId] = pauseOutput
 
     if (pauseBlockName) {
-      blockNameMappingWithPause[pauseBlockName] = pauseBlockId
       blockNameMappingWithPause[normalizeName(pauseBlockName)] = pauseBlockId
     }
 
diff --git a/apps/sim/executor/handlers/response/response-handler.ts b/apps/sim/executor/handlers/response/response-handler.ts
index 1af1bd9f3..94bcf35e4 100644
--- a/apps/sim/executor/handlers/response/response-handler.ts
+++ b/apps/sim/executor/handlers/response/response-handler.ts
@@ -1,6 +1,6 @@
 import { createLogger } from '@/lib/logs/console/logger'
 import type { BlockOutput } from '@/blocks/types'
-import { BlockType, HTTP } from '@/executor/constants'
+import { BlockType, HTTP, REFERENCE } from '@/executor/constants'
 import type { BlockHandler, ExecutionContext } from '@/executor/types'
 import type { SerializedBlock } from '@/serializer/types'
 
@@ -220,7 +220,11 @@ export class ResponseBlockHandler implements BlockHandler {
   }
 
   private isVariableReference(value: any): boolean {
-    return typeof value === 'string' && value.trim().startsWith('<') && value.trim().includes('>')
+    return (
+      typeof value === 'string' &&
+      value.trim().startsWith(REFERENCE.START) &&
+      value.trim().includes(REFERENCE.END)
+    )
   }
 
   private parseObjectStrings(data: any): any {
diff --git a/apps/sim/executor/utils/block-data.ts b/apps/sim/executor/utils/block-data.ts
index 64ae2097a..fc7b26ae3 100644
--- a/apps/sim/executor/utils/block-data.ts
+++ b/apps/sim/executor/utils/block-data.ts
@@ -1,3 +1,4 @@
+import { normalizeName } from '@/executor/constants'
 import type { ExecutionContext } from '@/executor/types'
 
 export interface BlockDataCollection {
@@ -14,9 +15,7 @@ export function collectBlockData(ctx: ExecutionContext): BlockDataCollection {
       blockData[id] = state.output
       const workflowBlock = ctx.workflow?.blocks?.find((b) => b.id === id)
       if (workflowBlock?.metadata?.name) {
-        blockNameMapping[workflowBlock.metadata.name] = id
-        const normalized = workflowBlock.metadata.name.replace(/\s+/g, '').toLowerCase()
-        blockNameMapping[normalized] = id
+        blockNameMapping[normalizeName(workflowBlock.metadata.name)] = id
       }
     }
   }
diff --git a/apps/sim/executor/variables/resolver.ts b/apps/sim/executor/variables/resolver.ts
index bcf34d82e..9080faab7 100644
--- a/apps/sim/executor/variables/resolver.ts
+++ b/apps/sim/executor/variables/resolver.ts
@@ -1,8 +1,8 @@
 import { createLogger } from '@/lib/logs/console/logger'
-import { BlockType, REFERENCE } from '@/executor/constants'
+import { BlockType } from '@/executor/constants'
 import type { ExecutionState, LoopScope } from '@/executor/execution/state'
 import type { ExecutionContext } from '@/executor/types'
-import { replaceValidReferences } from '@/executor/utils/reference-validation'
+import { createEnvVarPattern, replaceValidReferences } from '@/executor/utils/reference-validation'
 import { BlockResolver } from '@/executor/variables/resolvers/block'
 import { EnvResolver } from '@/executor/variables/resolvers/env'
 import { LoopResolver } from '@/executor/variables/resolvers/loop'
@@ -185,8 +185,7 @@ export class VariableResolver {
       throw replacementError
     }
 
-    const envRegex = new RegExp(`${REFERENCE.ENV_VAR_START}([^}]+)${REFERENCE.ENV_VAR_END}`, 'g')
-    result = result.replace(envRegex, (match) => {
+    result = result.replace(createEnvVarPattern(), (match) => {
       const resolved = this.resolveReference(match, resolutionContext)
       return typeof resolved === 'string' ? resolved : match
     })
@@ -236,8 +235,7 @@ export class VariableResolver {
       throw replacementError
     }
 
-    const envRegex = new RegExp(`${REFERENCE.ENV_VAR_START}([^}]+)${REFERENCE.ENV_VAR_END}`, 'g')
-    result = result.replace(envRegex, (match) => {
+    result = result.replace(createEnvVarPattern(), (match) => {
       const resolved = this.resolveReference(match, resolutionContext)
       return typeof resolved === 'string' ? resolved : match
     })
diff --git a/apps/sim/executor/variables/resolvers/block.ts b/apps/sim/executor/variables/resolvers/block.ts
index 253498ed3..5bd9fd6e6 100644
--- a/apps/sim/executor/variables/resolvers/block.ts
+++ b/apps/sim/executor/variables/resolvers/block.ts
@@ -1,22 +1,24 @@
-import { isReference, parseReferencePath, SPECIAL_REFERENCE_PREFIXES } from '@/executor/constants'
+import {
+  isReference,
+  normalizeName,
+  parseReferencePath,
+  SPECIAL_REFERENCE_PREFIXES,
+} from '@/executor/constants'
 import {
   navigatePath,
   type ResolutionContext,
   type Resolver,
 } from '@/executor/variables/resolvers/reference'
 import type { SerializedWorkflow } from '@/serializer/types'
-import { normalizeName } from '@/stores/workflows/utils'
 
 export class BlockResolver implements Resolver {
-  private blockByNormalizedName: Map<string, string>
+  private nameToBlockId: Map<string, string>
 
   constructor(private workflow: SerializedWorkflow) {
-    this.blockByNormalizedName = new Map()
+    this.nameToBlockId = new Map()
     for (const block of workflow.blocks) {
-      this.blockByNormalizedName.set(block.id, block.id)
       if (block.metadata?.name) {
-        const normalized = normalizeName(block.metadata.name)
-        this.blockByNormalizedName.set(normalized, block.id)
+        this.nameToBlockId.set(normalizeName(block.metadata.name), block.id)
       }
     }
   }
@@ -80,11 +82,7 @@ export class BlockResolver implements Resolver {
   }
 
   private findBlockIdByName(name: string): string | undefined {
-    if (this.blockByNormalizedName.has(name)) {
-      return this.blockByNormalizedName.get(name)
-    }
-    const normalized = normalizeName(name)
-    return this.blockByNormalizedName.get(normalized)
+    return this.nameToBlockId.get(normalizeName(name))
   }
 
   public formatValueForBlock(
diff --git a/apps/sim/executor/variables/resolvers/parallel.ts b/apps/sim/executor/variables/resolvers/parallel.ts
index 78fca1f9f..1f992a023 100644
--- a/apps/sim/executor/variables/resolvers/parallel.ts
+++ b/apps/sim/executor/variables/resolvers/parallel.ts
@@ -117,7 +117,7 @@ export class ParallelResolver implements Resolver {
     // String handling
     if (typeof rawItems === 'string') {
       // Skip references - they should be resolved by the variable resolver
-      if (rawItems.startsWith('<')) {
+      if (rawItems.startsWith(REFERENCE.START)) {
         return []
       }
 
diff --git a/apps/sim/executor/variables/resolvers/workflow.ts b/apps/sim/executor/variables/resolvers/workflow.ts
index 2e00912df..c2acf26aa 100644
--- a/apps/sim/executor/variables/resolvers/workflow.ts
+++ b/apps/sim/executor/variables/resolvers/workflow.ts
@@ -1,12 +1,11 @@
 import { createLogger } from '@/lib/logs/console/logger'
 import { VariableManager } from '@/lib/workflows/variables/variable-manager'
-import { isReference, parseReferencePath, REFERENCE } from '@/executor/constants'
+import { isReference, normalizeName, parseReferencePath, REFERENCE } from '@/executor/constants'
 import {
   navigatePath,
   type ResolutionContext,
   type Resolver,
 } from '@/executor/variables/resolvers/reference'
-import { normalizeName } from '@/stores/workflows/utils'
 
 const logger = createLogger('WorkflowResolver')
 
diff --git a/apps/sim/lib/copilot/process-contents.ts b/apps/sim/lib/copilot/process-contents.ts
index 3bf6cf564..6c362a2d5 100644
--- a/apps/sim/lib/copilot/process-contents.ts
+++ b/apps/sim/lib/copilot/process-contents.ts
@@ -4,6 +4,7 @@ import { and, eq, isNull } from 'drizzle-orm'
 import { createLogger } from '@/lib/logs/console/logger'
 import { loadWorkflowFromNormalizedTables } from '@/lib/workflows/persistence/utils'
 import { sanitizeForCopilot } from '@/lib/workflows/sanitization/json-sanitizer'
+import { escapeRegExp } from '@/executor/constants'
 import type { ChatContext } from '@/stores/panel/copilot/types'
 
 export type AgentContextType =
@@ -153,10 +154,6 @@ export async function processContextsServer(
   return filtered
 }
 
-function escapeRegExp(input: string): string {
-  return input.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
-}
-
 function sanitizeMessageForDocs(rawMessage: string, contexts: ChatContext[] | undefined): string {
   if (!rawMessage) return ''
   if (!Array.isArray(contexts) || contexts.length === 0) {
diff --git a/apps/sim/lib/copilot/tools/client/workflow/block-output-utils.ts b/apps/sim/lib/copilot/tools/client/workflow/block-output-utils.ts
index a30ca07a5..4916cb770 100644
--- a/apps/sim/lib/copilot/tools/client/workflow/block-output-utils.ts
+++ b/apps/sim/lib/copilot/tools/client/workflow/block-output-utils.ts
@@ -4,10 +4,10 @@ import {
 } from '@/lib/core/utils/response-format'
 import { getBlockOutputPaths } from '@/lib/workflows/blocks/block-outputs'
 import { getBlock } from '@/blocks'
+import { normalizeName } from '@/executor/constants'
 import { useVariablesStore } from '@/stores/panel/variables/store'
 import type { Variable } from '@/stores/panel/variables/types'
 import { useSubBlockStore } from '@/stores/workflows/subblock/store'
-import { normalizeName } from '@/stores/workflows/utils'
 import type { BlockState, Loop, Parallel } from '@/stores/workflows/workflow/types'
 
 export interface WorkflowContext {
diff --git a/apps/sim/lib/copilot/tools/client/workflow/get-block-outputs.ts b/apps/sim/lib/copilot/tools/client/workflow/get-block-outputs.ts
index b27ebd402..d99ecf94d 100644
--- a/apps/sim/lib/copilot/tools/client/workflow/get-block-outputs.ts
+++ b/apps/sim/lib/copilot/tools/client/workflow/get-block-outputs.ts
@@ -16,8 +16,8 @@ import {
   type GetBlockOutputsResultType,
 } from '@/lib/copilot/tools/shared/schemas'
 import { createLogger } from '@/lib/logs/console/logger'
+import { normalizeName } from '@/executor/constants'
 import { useWorkflowRegistry } from '@/stores/workflows/registry/store'
-import { normalizeName } from '@/stores/workflows/utils'
 import { useWorkflowStore } from '@/stores/workflows/workflow/store'
 
 const logger = createLogger('GetBlockOutputsClientTool')
diff --git a/apps/sim/lib/copilot/tools/server/workflow/edit-workflow.ts b/apps/sim/lib/copilot/tools/server/workflow/edit-workflow.ts
index 909f3ee74..d12c554a0 100644
--- a/apps/sim/lib/copilot/tools/server/workflow/edit-workflow.ts
+++ b/apps/sim/lib/copilot/tools/server/workflow/edit-workflow.ts
@@ -12,6 +12,7 @@ import { isValidKey } from '@/lib/workflows/sanitization/key-validation'
 import { validateWorkflowState } from '@/lib/workflows/sanitization/validation'
 import { getAllBlocks, getBlock } from '@/blocks/registry'
 import type { SubBlockConfig } from '@/blocks/types'
+import { EDGE, normalizeName } from '@/executor/constants'
 import { generateLoopBlocks, generateParallelBlocks } from '@/stores/workflows/workflow/utils'
 import { TRIGGER_RUNTIME_SUBBLOCK_IDS } from '@/triggers/constants'
 
@@ -55,6 +56,7 @@ type SkippedItemType =
   | 'invalid_subblock_field'
   | 'missing_required_params'
   | 'invalid_subflow_parent'
+  | 'duplicate_block_name'
 
 /**
  * Represents an item that was skipped during operation application
@@ -80,6 +82,21 @@ function logSkippedItem(skippedItems: SkippedItem[], item: SkippedItem): void {
   skippedItems.push(item)
 }
 
+/**
+ * Finds an existing block with the same normalized name.
+ */
+function findBlockWithDuplicateNormalizedName(
+  blocks: Record<string, any>,
+  name: string,
+  excludeBlockId: string
+): [string, any] | undefined {
+  const normalizedName = normalizeName(name)
+  return Object.entries(blocks).find(
+    ([blockId, block]: [string, any]) =>
+      blockId !== excludeBlockId && normalizeName(block.name || '') === normalizedName
+  )
+}
+
 /**
  * Result of input validation
  */
@@ -773,10 +790,10 @@ function validateSourceHandleForBlock(
       }
 
     case 'condition': {
-      if (!sourceHandle.startsWith('condition-')) {
+      if (!sourceHandle.startsWith(EDGE.CONDITION_PREFIX)) {
         return {
           valid: false,
-          error: `Invalid source handle "${sourceHandle}" for condition block. Must start with "condition-"`,
+          error: `Invalid source handle "${sourceHandle}" for condition block. Must start with "${EDGE.CONDITION_PREFIX}"`,
         }
       }
 
@@ -792,12 +809,12 @@ function validateSourceHandleForBlock(
     }
 
     case 'router':
-      if (sourceHandle === 'source' || sourceHandle.startsWith('router-')) {
+      if (sourceHandle === 'source' || sourceHandle.startsWith(EDGE.ROUTER_PREFIX)) {
         return { valid: true }
       }
       return {
         valid: false,
-        error: `Invalid source handle "${sourceHandle}" for router block. Valid handles: source, router-{targetId}, error`,
+        error: `Invalid source handle "${sourceHandle}" for router block. Valid handles: source, ${EDGE.ROUTER_PREFIX}{targetId}, error`,
       }
 
     default:
@@ -1387,7 +1404,39 @@ function applyOperationsToWorkflowState(
             block.type = params.type
           }
         }
-        if (params?.name !== undefined) block.name = params.name
+        if (params?.name !== undefined) {
+          if (!normalizeName(params.name)) {
+            logSkippedItem(skippedItems, {
+              type: 'missing_required_params',
+              operationType: 'edit',
+              blockId: block_id,
+              reason: `Cannot rename to empty name`,
+              details: { requestedName: params.name },
+            })
+          } else {
+            const conflictingBlock = findBlockWithDuplicateNormalizedName(
+              modifiedState.blocks,
+              params.name,
+              block_id
+            )
+
+            if (conflictingBlock) {
+              logSkippedItem(skippedItems, {
+                type: 'duplicate_block_name',
+                operationType: 'edit',
+                blockId: block_id,
+                reason: `Cannot rename to "${params.name}" - conflicts with "${conflictingBlock[1].name}"`,
+                details: {
+                  requestedName: params.name,
+                  conflictingBlockId: conflictingBlock[0],
+                  conflictingBlockName: conflictingBlock[1].name,
+                },
+              })
+            } else {
+              block.name = params.name
+            }
+          }
+        }
 
         // Handle trigger mode toggle
         if (typeof params?.triggerMode === 'boolean') {
@@ -1571,7 +1620,7 @@ function applyOperationsToWorkflowState(
       }
 
       case 'add': {
-        if (!params?.type || !params?.name) {
+        if (!params?.type || !params?.name || !normalizeName(params.name)) {
           logSkippedItem(skippedItems, {
             type: 'missing_required_params',
             operationType: 'add',
@@ -1582,6 +1631,27 @@ function applyOperationsToWorkflowState(
           break
         }
 
+        const conflictingBlock = findBlockWithDuplicateNormalizedName(
+          modifiedState.blocks,
+          params.name,
+          block_id
+        )
+
+        if (conflictingBlock) {
+          logSkippedItem(skippedItems, {
+            type: 'duplicate_block_name',
+            operationType: 'add',
+            blockId: block_id,
+            reason: `Block name "${params.name}" conflicts with existing block "${conflictingBlock[1].name}"`,
+            details: {
+              requestedName: params.name,
+              conflictingBlockId: conflictingBlock[0],
+              conflictingBlockName: conflictingBlock[1].name,
+            },
+          })
+          break
+        }
+
         // Special container types (loop, parallel) are not in the block registry but are valid
         const isContainerType = params.type === 'loop' || params.type === 'parallel'
 
diff --git a/apps/sim/lib/core/security/input-validation.test.ts b/apps/sim/lib/core/security/input-validation.test.ts
index 616751995..4af48e331 100644
--- a/apps/sim/lib/core/security/input-validation.test.ts
+++ b/apps/sim/lib/core/security/input-validation.test.ts
@@ -8,7 +8,6 @@ import {
   validateNumericId,
   validatePathSegment,
   validateUrlWithDNS,
-  validateUUID,
 } from '@/lib/core/security/input-validation'
 import { sanitizeForLogging } from '@/lib/core/security/redaction'
 
@@ -194,54 +193,6 @@ describe('validatePathSegment', () => {
   })
 })
 
-describe('validateUUID', () => {
-  describe('valid UUIDs', () => {
-    it.concurrent('should accept valid UUID v4', () => {
-      const result = validateUUID('550e8400-e29b-41d4-a716-446655440000')
-      expect(result.isValid).toBe(true)
-    })
-
-    it.concurrent('should accept UUID with uppercase letters', () => {
-      const result = validateUUID('550E8400-E29B-41D4-A716-446655440000')
-      expect(result.isValid).toBe(true)
-      expect(result.sanitized).toBe('550e8400-e29b-41d4-a716-446655440000')
-    })
-
-    it.concurrent('should normalize UUID to lowercase', () => {
-      const result = validateUUID('550E8400-E29B-41D4-A716-446655440000')
-      expect(result.sanitized).toBe('550e8400-e29b-41d4-a716-446655440000')
-    })
-  })
-
-  describe('invalid UUIDs', () => {
-    it.concurrent('should reject non-UUID strings', () => {
-      const result = validateUUID('not-a-uuid')
-      expect(result.isValid).toBe(false)
-      expect(result.error).toContain('valid UUID')
-    })
-
-    it.concurrent('should reject UUID with wrong version', () => {
-      const result = validateUUID('550e8400-e29b-31d4-a716-446655440000') // version 3
-      expect(result.isValid).toBe(false)
-    })
-
-    it.concurrent('should reject UUID with wrong variant', () => {
-      const result = validateUUID('550e8400-e29b-41d4-1716-446655440000') // wrong variant
-      expect(result.isValid).toBe(false)
-    })
-
-    it.concurrent('should reject empty string', () => {
-      const result = validateUUID('')
-      expect(result.isValid).toBe(false)
-    })
-
-    it.concurrent('should reject null', () => {
-      const result = validateUUID(null)
-      expect(result.isValid).toBe(false)
-    })
-  })
-})
-
 describe('validateAlphanumericId', () => {
   it.concurrent('should accept alphanumeric IDs', () => {
     const result = validateAlphanumericId('user123')
diff --git a/apps/sim/lib/core/security/input-validation.ts b/apps/sim/lib/core/security/input-validation.ts
index e84c7f8f4..8fd18e533 100644
--- a/apps/sim/lib/core/security/input-validation.ts
+++ b/apps/sim/lib/core/security/input-validation.ts
@@ -171,46 +171,6 @@ export function validatePathSegment(
   return { isValid: true, sanitized: value }
 }
 
-/**
- * Validates a UUID (v4 format)
- *
- * @param value - The UUID to validate
- * @param paramName - Name of the parameter for error messages
- * @returns ValidationResult
- *
- * @example
- * ```typescript
- * const result = validateUUID(workflowId, 'workflowId')
- * if (!result.isValid) {
- *   return NextResponse.json({ error: result.error }, { status: 400 })
- * }
- * ```
- */
-export function validateUUID(
-  value: string | null | undefined,
-  paramName = 'UUID'
-): ValidationResult {
-  if (value === null || value === undefined || value === '') {
-    return {
-      isValid: false,
-      error: `${paramName} is required`,
-    }
-  }
-
-  // UUID v4 pattern
-  const uuidPattern = /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i
-
-  if (!uuidPattern.test(value)) {
-    logger.warn('Invalid UUID format', { paramName, value: value.substring(0, 50) })
-    return {
-      isValid: false,
-      error: `${paramName} must be a valid UUID`,
-    }
-  }
-
-  return { isValid: true, sanitized: value.toLowerCase() }
-}
-
 /**
  * Validates an alphanumeric ID (letters, numbers, hyphens, underscores only)
  *
diff --git a/apps/sim/lib/logs/execution/trace-spans/trace-spans.test.ts b/apps/sim/lib/logs/execution/trace-spans/trace-spans.test.ts
index 829f8cad6..c92507ecf 100644
--- a/apps/sim/lib/logs/execution/trace-spans/trace-spans.test.ts
+++ b/apps/sim/lib/logs/execution/trace-spans/trace-spans.test.ts
@@ -1,8 +1,6 @@
 import { describe, expect, test } from 'vitest'
-import {
-  buildTraceSpans,
-  stripCustomToolPrefix,
-} from '@/lib/logs/execution/trace-spans/trace-spans'
+import { buildTraceSpans } from '@/lib/logs/execution/trace-spans/trace-spans'
+import { stripCustomToolPrefix } from '@/executor/constants'
 import type { ExecutionResult } from '@/executor/types'
 
 describe('buildTraceSpans', () => {
diff --git a/apps/sim/lib/logs/execution/trace-spans/trace-spans.ts b/apps/sim/lib/logs/execution/trace-spans/trace-spans.ts
index 0f35e1d8d..da0207729 100644
--- a/apps/sim/lib/logs/execution/trace-spans/trace-spans.ts
+++ b/apps/sim/lib/logs/execution/trace-spans/trace-spans.ts
@@ -1,6 +1,6 @@
 import { createLogger } from '@/lib/logs/console/logger'
 import type { ToolCall, TraceSpan } from '@/lib/logs/types'
-import { isWorkflowBlockType } from '@/executor/constants'
+import { isWorkflowBlockType, stripCustomToolPrefix } from '@/executor/constants'
 import type { ExecutionResult } from '@/executor/types'
 
 const logger = createLogger('TraceSpans')
@@ -769,7 +769,3 @@ function ensureNestedWorkflowsProcessed(span: TraceSpan): TraceSpan {
 
   return processedSpan
 }
-
-export function stripCustomToolPrefix(name: string) {
-  return name.startsWith('custom_') ? name.replace('custom_', '') : name
-}
diff --git a/apps/sim/lib/mcp/service.ts b/apps/sim/lib/mcp/service.ts
index 1e95dd706..3626c0412 100644
--- a/apps/sim/lib/mcp/service.ts
+++ b/apps/sim/lib/mcp/service.ts
@@ -25,6 +25,8 @@ import type {
   McpTransport,
 } from '@/lib/mcp/types'
 import { MCP_CONSTANTS } from '@/lib/mcp/utils'
+import { REFERENCE } from '@/executor/constants'
+import { createEnvVarPattern } from '@/executor/utils/reference-validation'
 
 const logger = createLogger('McpService')
 
@@ -49,14 +51,17 @@ class McpService {
    * Resolve environment variables in strings
    */
   private resolveEnvVars(value: string, envVars: Record<string, string>): string {
-    const envMatches = value.match(/\{\{([^}]+)\}\}/g)
+    const envVarPattern = createEnvVarPattern()
+    const envMatches = value.match(envVarPattern)
     if (!envMatches) return value
 
     let resolvedValue = value
     const missingVars: string[] = []
 
     for (const match of envMatches) {
-      const envKey = match.slice(2, -2).trim()
+      const envKey = match
+        .slice(REFERENCE.ENV_VAR_START.length, -REFERENCE.ENV_VAR_END.length)
+        .trim()
       const envValue = envVars[envKey]
 
       if (envValue === undefined) {
diff --git a/apps/sim/lib/mcp/utils.ts b/apps/sim/lib/mcp/utils.ts
index eee16742f..1a446b675 100644
--- a/apps/sim/lib/mcp/utils.ts
+++ b/apps/sim/lib/mcp/utils.ts
@@ -1,5 +1,6 @@
 import { NextResponse } from 'next/server'
 import type { McpApiResponse } from '@/lib/mcp/types'
+import { isMcpTool, MCP } from '@/executor/constants'
 
 /**
  * MCP-specific constants
@@ -124,7 +125,7 @@ export function categorizeError(error: unknown): { message: string; status: numb
  * Create standardized MCP tool ID from server ID and tool name
  */
 export function createMcpToolId(serverId: string, toolName: string): string {
-  const normalizedServerId = serverId.startsWith('mcp-') ? serverId : `mcp-${serverId}`
+  const normalizedServerId = isMcpTool(serverId) ? serverId : `${MCP.TOOL_PREFIX}${serverId}`
   return `${normalizedServerId}-${toolName}`
 }
 
diff --git a/apps/sim/lib/uploads/contexts/execution/utils.ts b/apps/sim/lib/uploads/contexts/execution/utils.ts
index 9e36ec72e..ab4b98aad 100644
--- a/apps/sim/lib/uploads/contexts/execution/utils.ts
+++ b/apps/sim/lib/uploads/contexts/execution/utils.ts
@@ -1,3 +1,4 @@
+import { isUuid, sanitizeFileName } from '@/executor/constants'
 import type { UserFile } from '@/executor/types'
 
 /**
@@ -15,7 +16,7 @@ export interface ExecutionContext {
  */
 export function generateExecutionFileKey(context: ExecutionContext, fileName: string): string {
   const { workspaceId, workflowId, executionId } = context
-  const safeFileName = fileName.replace(/\s+/g, '-').replace(/[^a-zA-Z0-9.-]/g, '_')
+  const safeFileName = sanitizeFileName(fileName)
   return `execution/${workspaceId}/${workflowId}/${executionId}/${safeFileName}`
 }
 
@@ -26,17 +27,7 @@ export function generateFileId(): string {
   return `file_${Date.now()}_${Math.random().toString(36).substring(2, 9)}`
 }
 
-/**
- * UUID pattern for validating execution context IDs
- */
-const UUID_PATTERN = /^[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}$/i
-
-/**
- * Check if a string matches UUID pattern
- */
-export function isUuid(str: string): boolean {
-  return UUID_PATTERN.test(str)
-}
+export { isUuid }
 
 /**
  * Check if a key matches execution file pattern
diff --git a/apps/sim/lib/uploads/contexts/workspace/workspace-file-manager.ts b/apps/sim/lib/uploads/contexts/workspace/workspace-file-manager.ts
index fc4cf1f29..d4a0d17a0 100644
--- a/apps/sim/lib/uploads/contexts/workspace/workspace-file-manager.ts
+++ b/apps/sim/lib/uploads/contexts/workspace/workspace-file-manager.ts
@@ -19,6 +19,7 @@ import {
   uploadFile,
 } from '@/lib/uploads/core/storage-service'
 import { getFileMetadataByKey, insertFileMetadata } from '@/lib/uploads/server/metadata'
+import { isUuid, sanitizeFileName } from '@/executor/constants'
 import type { UserFile } from '@/executor/types'
 
 const logger = createLogger('WorkspaceFileStorage')
@@ -36,11 +37,6 @@ export interface WorkspaceFileRecord {
   uploadedAt: Date
 }
 
-/**
- * UUID pattern for validating workspace IDs
- */
-const UUID_PATTERN = /^[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}$/i
-
 /**
  * Workspace file key pattern: workspace/{workspaceId}/{timestamp}-{random}-{filename}
  */
@@ -73,7 +69,7 @@ export function parseWorkspaceFileKey(key: string): string | null {
   }
 
   const workspaceId = match[1]
-  return UUID_PATTERN.test(workspaceId) ? workspaceId : null
+  return isUuid(workspaceId) ? workspaceId : null
 }
 
 /**
@@ -83,7 +79,7 @@ export function parseWorkspaceFileKey(key: string): string | null {
 export function generateWorkspaceFileKey(workspaceId: string, fileName: string): string {
   const timestamp = Date.now()
   const random = Math.random().toString(36).substring(2, 9)
-  const safeFileName = fileName.replace(/\s+/g, '-').replace(/[^a-zA-Z0-9.-]/g, '_')
+  const safeFileName = sanitizeFileName(fileName)
   return `workspace/${workspaceId}/${timestamp}-${random}-${safeFileName}`
 }
 
diff --git a/apps/sim/lib/uploads/providers/blob/client.ts b/apps/sim/lib/uploads/providers/blob/client.ts
index 32751e232..0b2cc89d1 100644
--- a/apps/sim/lib/uploads/providers/blob/client.ts
+++ b/apps/sim/lib/uploads/providers/blob/client.ts
@@ -8,6 +8,7 @@ import type {
 } from '@/lib/uploads/providers/blob/types'
 import type { FileInfo } from '@/lib/uploads/shared/types'
 import { sanitizeStorageMetadata } from '@/lib/uploads/utils/file-utils'
+import { sanitizeFileName } from '@/executor/constants'
 
 type BlobServiceClientInstance = Awaited<
   ReturnType<typeof import('@azure/storage-blob').BlobServiceClient.fromConnectionString>
@@ -79,7 +80,7 @@ export async function uploadToBlob(
     shouldPreserveKey = preserveKey ?? false
   }
 
-  const safeFileName = fileName.replace(/\s+/g, '-') // Replace spaces with hyphens
+  const safeFileName = sanitizeFileName(fileName)
   const uniqueKey = shouldPreserveKey ? fileName : `${Date.now()}-${safeFileName}`
 
   const blobServiceClient = await getBlobServiceClient()
@@ -357,7 +358,7 @@ export async function initiateMultipartUpload(
     containerName = BLOB_CONFIG.containerName
   }
 
-  const safeFileName = fileName.replace(/\s+/g, '-').replace(/[^a-zA-Z0-9.-]/g, '_')
+  const safeFileName = sanitizeFileName(fileName)
   const { v4: uuidv4 } = await import('uuid')
   const uniqueKey = `kb/${uuidv4()}-${safeFileName}`
 
diff --git a/apps/sim/lib/uploads/providers/s3/client.ts b/apps/sim/lib/uploads/providers/s3/client.ts
index 800477b1a..1a6e27e2e 100644
--- a/apps/sim/lib/uploads/providers/s3/client.ts
+++ b/apps/sim/lib/uploads/providers/s3/client.ts
@@ -22,6 +22,7 @@ import {
   sanitizeFilenameForMetadata,
   sanitizeStorageMetadata,
 } from '@/lib/uploads/utils/file-utils'
+import { sanitizeFileName } from '@/executor/constants'
 
 let _s3Client: S3Client | null = null
 
@@ -84,7 +85,7 @@ export async function uploadToS3(
     shouldSkipTimestamp = skipTimestampPrefix ?? false
   }
 
-  const safeFileName = fileName.replace(/\s+/g, '-') // Replace spaces with hyphens
+  const safeFileName = sanitizeFileName(fileName)
   const uniqueKey = shouldSkipTimestamp ? fileName : `${Date.now()}-${safeFileName}`
 
   const s3Client = getS3Client()
@@ -223,7 +224,7 @@ export async function initiateS3MultipartUpload(
   const config = customConfig || { bucket: S3_KB_CONFIG.bucket, region: S3_KB_CONFIG.region }
   const s3Client = getS3Client()
 
-  const safeFileName = fileName.replace(/\s+/g, '-').replace(/[^a-zA-Z0-9.-]/g, '_')
+  const safeFileName = sanitizeFileName(fileName)
   const { v4: uuidv4 } = await import('uuid')
   const uniqueKey = `kb/${uuidv4()}-${safeFileName}`
 
diff --git a/apps/sim/lib/uploads/utils/file-utils.ts b/apps/sim/lib/uploads/utils/file-utils.ts
index 69042f7ef..623c1bf3e 100644
--- a/apps/sim/lib/uploads/utils/file-utils.ts
+++ b/apps/sim/lib/uploads/utils/file-utils.ts
@@ -1,6 +1,7 @@
 import type { Logger } from '@/lib/logs/console/logger'
 import type { StorageContext } from '@/lib/uploads'
 import { ACCEPTED_FILE_TYPES, SUPPORTED_DOCUMENT_EXTENSIONS } from '@/lib/uploads/utils/validation'
+import { isUuid } from '@/executor/constants'
 import type { UserFile } from '@/executor/types'
 
 export interface FileAttachment {
@@ -625,11 +626,9 @@ export function extractCleanFilename(urlOrPath: string): string {
 export function extractWorkspaceIdFromExecutionKey(key: string): string | null {
   const segments = key.split('/')
 
-  const UUID_PATTERN = /^[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}$/i
-
   if (segments[0] === 'execution' && segments.length >= 5) {
     const workspaceId = segments[1]
-    if (workspaceId && UUID_PATTERN.test(workspaceId)) {
+    if (workspaceId && isUuid(workspaceId)) {
       return workspaceId
     }
   }
diff --git a/apps/sim/lib/webhooks/processor.ts b/apps/sim/lib/webhooks/processor.ts
index 47a84cc33..2873b59fd 100644
--- a/apps/sim/lib/webhooks/processor.ts
+++ b/apps/sim/lib/webhooks/processor.ts
@@ -14,6 +14,8 @@ import {
   verifyProviderWebhook,
 } from '@/lib/webhooks/utils.server'
 import { executeWebhookJob } from '@/background/webhook-execution'
+import { REFERENCE } from '@/executor/constants'
+import { createEnvVarPattern } from '@/executor/utils/reference-validation'
 
 const logger = createLogger('WebhookProcessor')
 
@@ -170,12 +172,13 @@ export async function findWebhookAndWorkflow(
  * @returns String with all {{VARIABLE}} references replaced
  */
 function resolveEnvVars(value: string, envVars: Record<string, string>): string {
-  const envMatches = value.match(/\{\{([^}]+)\}\}/g)
+  const envVarPattern = createEnvVarPattern()
+  const envMatches = value.match(envVarPattern)
   if (!envMatches) return value
 
   let resolvedValue = value
   for (const match of envMatches) {
-    const envKey = match.slice(2, -2).trim()
+    const envKey = match.slice(REFERENCE.ENV_VAR_START.length, -REFERENCE.ENV_VAR_END.length).trim()
     const envValue = envVars[envKey]
     if (envValue !== undefined) {
       resolvedValue = resolvedValue.replaceAll(match, envValue)
diff --git a/apps/sim/lib/workflows/autolayout/core.ts b/apps/sim/lib/workflows/autolayout/core.ts
index 745b4865e..1fde83821 100644
--- a/apps/sim/lib/workflows/autolayout/core.ts
+++ b/apps/sim/lib/workflows/autolayout/core.ts
@@ -11,6 +11,7 @@ import {
   prepareBlockMetrics,
 } from '@/lib/workflows/autolayout/utils'
 import { BLOCK_DIMENSIONS, HANDLE_POSITIONS } from '@/lib/workflows/blocks/block-dimensions'
+import { EDGE } from '@/executor/constants'
 import type { BlockState } from '@/stores/workflows/workflow/types'
 
 const logger = createLogger('AutoLayout:Core')
@@ -31,8 +32,8 @@ function getSourceHandleYOffset(block: BlockState, sourceHandle?: string | null)
     return HANDLE_POSITIONS.SUBFLOW_START_Y_OFFSET
   }
 
-  if (block.type === 'condition' && sourceHandle?.startsWith('condition-')) {
-    const conditionId = sourceHandle.replace('condition-', '')
+  if (block.type === 'condition' && sourceHandle?.startsWith(EDGE.CONDITION_PREFIX)) {
+    const conditionId = sourceHandle.replace(EDGE.CONDITION_PREFIX, '')
     try {
       const conditionsValue = block.subBlocks?.conditions?.value
       if (typeof conditionsValue === 'string' && conditionsValue) {
diff --git a/apps/sim/lib/workflows/blocks/block-path-calculator.ts b/apps/sim/lib/workflows/blocks/block-path-calculator.ts
index 939e47468..a67094480 100644
--- a/apps/sim/lib/workflows/blocks/block-path-calculator.ts
+++ b/apps/sim/lib/workflows/blocks/block-path-calculator.ts
@@ -97,41 +97,4 @@ export class BlockPathCalculator {
 
     return accessibleMap
   }
-
-  /**
-   * Gets accessible block names for a specific block (for error messages).
-   *
-   * @param blockId - The block ID to get accessible names for
-   * @param workflow - The serialized workflow
-   * @param accessibleBlocksMap - Pre-calculated accessible blocks map
-   * @returns Array of accessible block names and aliases
-   */
-  static getAccessibleBlockNames(
-    blockId: string,
-    workflow: SerializedWorkflow,
-    accessibleBlocksMap: Map<string, Set<string>>
-  ): string[] {
-    const accessibleBlockIds = accessibleBlocksMap.get(blockId) || new Set<string>()
-    const names: string[] = []
-
-    // Create a map of block IDs to blocks for efficient lookup
-    const blockById = new Map(workflow.blocks.map((block) => [block.id, block]))
-
-    for (const accessibleBlockId of accessibleBlockIds) {
-      const block = blockById.get(accessibleBlockId)
-      if (block) {
-        // Add both the actual name and the normalized name
-        if (block.metadata?.name) {
-          names.push(block.metadata.name)
-          names.push(block.metadata.name.toLowerCase().replace(/\s+/g, ''))
-        }
-        names.push(accessibleBlockId)
-      }
-    }
-
-    // Add special aliases
-    names.push('start') // Always allow start alias
-
-    return [...new Set(names)] // Remove duplicates
-  }
 }
diff --git a/apps/sim/lib/workflows/executor/execution-core.ts b/apps/sim/lib/workflows/executor/execution-core.ts
index 11dc2a1f4..0607d01ac 100644
--- a/apps/sim/lib/workflows/executor/execution-core.ts
+++ b/apps/sim/lib/workflows/executor/execution-core.ts
@@ -16,8 +16,10 @@ import {
 import { TriggerUtils } from '@/lib/workflows/triggers/triggers'
 import { updateWorkflowRunCounts } from '@/lib/workflows/utils'
 import { Executor } from '@/executor'
+import { REFERENCE } from '@/executor/constants'
 import type { ExecutionCallbacks, ExecutionSnapshot } from '@/executor/execution/snapshot'
 import type { ExecutionResult } from '@/executor/types'
+import { createEnvVarPattern } from '@/executor/utils/reference-validation'
 import { Serializer } from '@/serializer'
 import { mergeSubblockState } from '@/stores/workflows/server-utils'
 
@@ -190,11 +192,19 @@ export async function executeWorkflowCore(
           (subAcc, [key, subBlock]) => {
             let value = subBlock.value
 
-            if (typeof value === 'string' && value.includes('{{') && value.includes('}}')) {
-              const matches = value.match(/{{([^}]+)}}/g)
+            if (
+              typeof value === 'string' &&
+              value.includes(REFERENCE.ENV_VAR_START) &&
+              value.includes(REFERENCE.ENV_VAR_END)
+            ) {
+              const envVarPattern = createEnvVarPattern()
+              const matches = value.match(envVarPattern)
               if (matches) {
                 for (const match of matches) {
-                  const varName = match.slice(2, -2)
+                  const varName = match.slice(
+                    REFERENCE.ENV_VAR_START.length,
+                    -REFERENCE.ENV_VAR_END.length
+                  )
                   const decryptedValue = decryptedEnvVars[varName]
                   if (decryptedValue !== undefined) {
                     value = (value as string).replace(match, decryptedValue)
@@ -218,7 +228,7 @@ export async function executeWorkflowCore(
       (acc, [blockId, blockState]) => {
         if (blockState.responseFormat && typeof blockState.responseFormat === 'string') {
           const responseFormatValue = blockState.responseFormat.trim()
-          if (responseFormatValue && !responseFormatValue.startsWith('<')) {
+          if (responseFormatValue && !responseFormatValue.startsWith(REFERENCE.START)) {
             try {
               acc[blockId] = {
                 ...blockState,
diff --git a/apps/sim/lib/workflows/operations/deployment-utils.ts b/apps/sim/lib/workflows/operations/deployment-utils.ts
index f46238bad..b5fcc3514 100644
--- a/apps/sim/lib/workflows/operations/deployment-utils.ts
+++ b/apps/sim/lib/workflows/operations/deployment-utils.ts
@@ -1,5 +1,6 @@
 import { createLogger } from '@/lib/logs/console/logger'
 import { resolveStartCandidates, StartBlockPath } from '@/lib/workflows/triggers/triggers'
+import { normalizeName, startsWithUuid } from '@/executor/constants'
 import { useSubBlockStore } from '@/stores/workflows/subblock/store'
 import { useWorkflowStore } from '@/stores/workflows/workflow/store'
 
@@ -74,13 +75,11 @@ export function getInputFormatExample(
       // Add streaming parameters if enabled and outputs are selected
       if (includeStreaming && selectedStreamingOutputs.length > 0) {
         exampleData.stream = true
-        // Convert blockId_attribute format to blockName.attribute format for display
-        const UUID_REGEX = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}/i
 
         const convertedOutputs = selectedStreamingOutputs
           .map((outputId) => {
             // If it starts with a UUID, convert to blockName.attribute format
-            if (UUID_REGEX.test(outputId)) {
+            if (startsWithUuid(outputId)) {
               const underscoreIndex = outputId.indexOf('_')
               if (underscoreIndex === -1) return null
 
@@ -90,9 +89,7 @@ export function getInputFormatExample(
               // Find the block by ID and get its name
               const block = blocks.find((b) => b.id === blockId)
               if (block?.name) {
-                // Normalize block name: lowercase and remove spaces
-                const normalizedBlockName = block.name.toLowerCase().replace(/\s+/g, '')
-                return `${normalizedBlockName}.${attribute}`
+                return `${normalizeName(block.name)}.${attribute}`
               }
               // Block not found (deleted), return null to filter out
               return null
@@ -104,7 +101,7 @@ export function getInputFormatExample(
               const blockName = parts[0]
               // Check if a block with this name exists
               const block = blocks.find(
-                (b) => b.name?.toLowerCase().replace(/\s+/g, '') === blockName.toLowerCase()
+                (b) => b.name && normalizeName(b.name) === normalizeName(blockName)
               )
               if (!block) {
                 // Block not found (deleted), return null to filter out
diff --git a/apps/sim/lib/workflows/sanitization/references.ts b/apps/sim/lib/workflows/sanitization/references.ts
index 8dc978aec..2290f150f 100644
--- a/apps/sim/lib/workflows/sanitization/references.ts
+++ b/apps/sim/lib/workflows/sanitization/references.ts
@@ -1,4 +1,4 @@
-import { normalizeName } from '@/stores/workflows/utils'
+import { normalizeName, REFERENCE } from '@/executor/constants'
 
 export const SYSTEM_REFERENCE_PREFIXES = new Set(['start', 'loop', 'parallel', 'variable'])
 
@@ -9,11 +9,11 @@ const LEADING_REFERENCE_PATTERN = /^[<>=!\s]*$/
 export function splitReferenceSegment(
   segment: string
 ): { leading: string; reference: string } | null {
-  if (!segment.startsWith('<') || !segment.endsWith('>')) {
+  if (!segment.startsWith(REFERENCE.START) || !segment.endsWith(REFERENCE.END)) {
     return null
   }
 
-  const lastOpenBracket = segment.lastIndexOf('<')
+  const lastOpenBracket = segment.lastIndexOf(REFERENCE.START)
   if (lastOpenBracket === -1) {
     return null
   }
@@ -21,7 +21,7 @@ export function splitReferenceSegment(
   const leading = lastOpenBracket > 0 ? segment.slice(0, lastOpenBracket) : ''
   const reference = segment.slice(lastOpenBracket)
 
-  if (!reference.startsWith('<') || !reference.endsWith('>')) {
+  if (!reference.startsWith(REFERENCE.START) || !reference.endsWith(REFERENCE.END)) {
     return null
   }
 
@@ -40,7 +40,7 @@ export function isLikelyReferenceSegment(segment: string): boolean {
     return false
   }
 
-  const inner = reference.slice(1, -1)
+  const inner = reference.slice(REFERENCE.START.length, -REFERENCE.END.length)
 
   if (!inner) {
     return false
@@ -58,10 +58,10 @@ export function isLikelyReferenceSegment(segment: string): boolean {
     return false
   }
 
-  if (inner.includes('.')) {
-    const dotIndex = inner.indexOf('.')
+  if (inner.includes(REFERENCE.PATH_DELIMITER)) {
+    const dotIndex = inner.indexOf(REFERENCE.PATH_DELIMITER)
     const beforeDot = inner.substring(0, dotIndex)
-    const afterDot = inner.substring(dotIndex + 1)
+    const afterDot = inner.substring(dotIndex + REFERENCE.PATH_DELIMITER.length)
 
     if (afterDot.includes(' ')) {
       return false
@@ -82,7 +82,8 @@ export function extractReferencePrefixes(value: string): Array<{ raw: string; pr
     return []
   }
 
-  const matches = value.match(/<[^>]+>/g)
+  const referencePattern = new RegExp(`${REFERENCE.START}[^${REFERENCE.END}]+${REFERENCE.END}`, 'g')
+  const matches = value.match(referencePattern)
   if (!matches) {
     return []
   }
@@ -105,8 +106,8 @@ export function extractReferencePrefixes(value: string): Array<{ raw: string; pr
       continue
     }
 
-    const inner = referenceSegment.slice(1, -1)
-    const [rawPrefix] = inner.split('.')
+    const inner = referenceSegment.slice(REFERENCE.START.length, -REFERENCE.END.length)
+    const [rawPrefix] = inner.split(REFERENCE.PATH_DELIMITER)
     if (!rawPrefix) {
       continue
     }
diff --git a/apps/sim/lib/workflows/sanitization/validation.ts b/apps/sim/lib/workflows/sanitization/validation.ts
index 9423b0113..7519383d4 100644
--- a/apps/sim/lib/workflows/sanitization/validation.ts
+++ b/apps/sim/lib/workflows/sanitization/validation.ts
@@ -1,5 +1,6 @@
 import { createLogger } from '@/lib/logs/console/logger'
 import { getBlock } from '@/blocks/registry'
+import { isCustomTool, isMcpTool } from '@/executor/constants'
 import type { WorkflowState } from '@/stores/workflows/workflow/types'
 import { getTool } from '@/tools/utils'
 
@@ -299,11 +300,7 @@ export function validateToolReference(
 ): string | null {
   if (!toolId) return null
 
-  // Check if it's a custom tool or MCP tool
-  const isCustomTool = toolId.startsWith('custom_')
-  const isMcpTool = toolId.startsWith('mcp-')
-
-  if (!isCustomTool && !isMcpTool) {
+  if (!isCustomTool(toolId) && !isMcpTool(toolId)) {
     // For built-in tools, verify they exist
     const tool = getTool(toolId)
     if (!tool) {
diff --git a/apps/sim/lib/workflows/utils.ts b/apps/sim/lib/workflows/utils.ts
index 4c69e23c1..21036588e 100644
--- a/apps/sim/lib/workflows/utils.ts
+++ b/apps/sim/lib/workflows/utils.ts
@@ -458,10 +458,6 @@ export function hasWorkflowChanged(
   return false
 }
 
-export function stripCustomToolPrefix(name: string) {
-  return name.startsWith('custom_') ? name.replace('custom_', '') : name
-}
-
 export const workflowHasResponseBlock = (executionResult: ExecutionResult): boolean => {
   if (
     !executionResult?.logs ||
diff --git a/apps/sim/providers/utils.ts b/apps/sim/providers/utils.ts
index 9344d3971..33485ac56 100644
--- a/apps/sim/providers/utils.ts
+++ b/apps/sim/providers/utils.ts
@@ -3,6 +3,7 @@ import type { CompletionUsage } from 'openai/resources/completions'
 import { getEnv, isTruthy } from '@/lib/core/config/env'
 import { isHosted } from '@/lib/core/config/feature-flags'
 import { createLogger, type Logger } from '@/lib/logs/console/logger'
+import { isCustomTool } from '@/executor/constants'
 import {
   getComputerUseModels,
   getEmbeddingModelPricing,
@@ -431,7 +432,7 @@ export async function transformBlockTool(
 
   let toolConfig: any
 
-  if (toolId.startsWith('custom_') && getToolAsync) {
+  if (isCustomTool(toolId) && getToolAsync) {
     toolConfig = await getToolAsync(toolId)
   } else {
     toolConfig = getTool(toolId)
diff --git a/apps/sim/serializer/index.ts b/apps/sim/serializer/index.ts
index 6500f7fb2..1e0425179 100644
--- a/apps/sim/serializer/index.ts
+++ b/apps/sim/serializer/index.ts
@@ -3,6 +3,7 @@ import { createLogger } from '@/lib/logs/console/logger'
 import { BlockPathCalculator } from '@/lib/workflows/blocks/block-path-calculator'
 import { getBlock } from '@/blocks'
 import type { SubBlockConfig } from '@/blocks/types'
+import { REFERENCE } from '@/executor/constants'
 import type { SerializedBlock, SerializedWorkflow } from '@/serializer/types'
 import type { BlockState, Loop, Parallel } from '@/stores/workflows/workflow/types'
 import { generateLoopBlocks, generateParallelBlocks } from '@/stores/workflows/workflow/utils'
@@ -351,7 +352,7 @@ export class Serializer {
       const trimmedValue = responseFormat.trim()
 
       // Check for variable references like <start.input>
-      if (trimmedValue.startsWith('<') && trimmedValue.includes('>')) {
+      if (trimmedValue.startsWith(REFERENCE.START) && trimmedValue.includes(REFERENCE.END)) {
         // Keep variable references as-is
         return trimmedValue
       }
diff --git a/apps/sim/stores/variables/store.ts b/apps/sim/stores/variables/store.ts
index aa3c54e01..c4bcb89ff 100644
--- a/apps/sim/stores/variables/store.ts
+++ b/apps/sim/stores/variables/store.ts
@@ -11,6 +11,7 @@ import type {
 } from '@/stores/variables/types'
 import { useWorkflowRegistry } from '@/stores/workflows/registry/store'
 import { useSubBlockStore } from '@/stores/workflows/subblock/store'
+import { normalizeName } from '@/stores/workflows/utils'
 
 const logger = createLogger('VariablesModalStore')
 
@@ -303,8 +304,8 @@ export const useVariablesStore = create<VariablesStore>()(
                   Object.entries(workflowValues).forEach(([blockId, blockValues]) => {
                     Object.entries(blockValues as Record<string, any>).forEach(
                       ([subBlockId, value]) => {
-                        const oldVarName = oldVariableName.replace(/\s+/g, '').toLowerCase()
-                        const newVarName = newName.replace(/\s+/g, '').toLowerCase()
+                        const oldVarName = normalizeName(oldVariableName)
+                        const newVarName = normalizeName(newName)
                         const regex = new RegExp(`<variable\\.${oldVarName}>`, 'gi')
 
                         updatedWorkflowValues[blockId][subBlockId] = updateReferences(
diff --git a/apps/sim/stores/workflows/subblock/utils.ts b/apps/sim/stores/workflows/subblock/utils.ts
index 578ebe141..b95b050d8 100644
--- a/apps/sim/stores/workflows/subblock/utils.ts
+++ b/apps/sim/stores/workflows/subblock/utils.ts
@@ -1,17 +1,7 @@
-// DEPRECATED: useEnvironmentStore import removed as autofill functions were removed
-
 /**
- * Checks if a value is an environment variable reference in the format {{ENV_VAR}}
+ * Re-exports env var utilities from executor constants for backward compatibility
  */
-export const isEnvVarReference = (value: string): boolean => {
-  // Check if the value looks like {{ENV_VAR}}
-  return /^\{\{[a-zA-Z0-9_-]+\}\}$/.test(value)
-}
-
-/**
- * Extracts the environment variable name from a reference like {{ENV_VAR}}
- */
-export const extractEnvVarName = (value: string): string | null => {
-  if (!isEnvVarReference(value)) return null
-  return value.slice(2, -2)
-}
+export {
+  extractEnvVarName,
+  isEnvVarReference,
+} from '@/executor/constants'
diff --git a/apps/sim/stores/workflows/utils.ts b/apps/sim/stores/workflows/utils.ts
index e7abd5603..a0da2e3e7 100644
--- a/apps/sim/stores/workflows/utils.ts
+++ b/apps/sim/stores/workflows/utils.ts
@@ -1,15 +1,8 @@
+import { normalizeName } from '@/executor/constants'
 import { useSubBlockStore } from '@/stores/workflows/subblock/store'
 import type { BlockState, SubBlockState } from '@/stores/workflows/workflow/types'
 
-/**
- * Normalizes a name for comparison by converting to lowercase and removing spaces.
- * Used for both block names and variable names to ensure consistent matching.
- * @param name - The name to normalize
- * @returns The normalized name
- */
-export function normalizeName(name: string): string {
-  return name.toLowerCase().replace(/\s+/g, '')
-}
+export { normalizeName }
 
 /**
  * Generates a unique block name by finding the highest number suffix among existing blocks
diff --git a/apps/sim/stores/workflows/workflow/store.test.ts b/apps/sim/stores/workflows/workflow/store.test.ts
index 1f18f8110..b8c5cd9ef 100644
--- a/apps/sim/stores/workflows/workflow/store.test.ts
+++ b/apps/sim/stores/workflows/workflow/store.test.ts
@@ -594,18 +594,18 @@ describe('workflow store', () => {
       }
     )
 
-    it.concurrent('should handle edge cases with empty or whitespace-only names', () => {
+    it.concurrent('should reject empty or whitespace-only names', () => {
       const { updateBlockName } = useWorkflowStore.getState()
 
       const result1 = updateBlockName('block1', '')
-      expect(result1.success).toBe(true)
+      expect(result1.success).toBe(false)
 
       const result2 = updateBlockName('block2', '   ')
-      expect(result2.success).toBe(true)
+      expect(result2.success).toBe(false)
 
       const state = useWorkflowStore.getState()
-      expect(state.blocks.block1.name).toBe('')
-      expect(state.blocks.block2.name).toBe('   ')
+      expect(state.blocks.block1.name).toBe('column ad')
+      expect(state.blocks.block2.name).toBe('Employee Length')
     })
 
     it.concurrent('should return false when trying to rename a non-existent block', () => {
diff --git a/apps/sim/stores/workflows/workflow/store.ts b/apps/sim/stores/workflows/workflow/store.ts
index cc5f41292..9504bf7c4 100644
--- a/apps/sim/stores/workflows/workflow/store.ts
+++ b/apps/sim/stores/workflows/workflow/store.ts
@@ -671,23 +671,21 @@ export const useWorkflowStore = create<WorkflowStore>()(
         const oldBlock = get().blocks[id]
         if (!oldBlock) return { success: false, changedSubblocks: [] }
 
-        // Check for normalized name collisions
         const normalizedNewName = normalizeName(name)
-        const currentBlocks = get().blocks
 
-        // Find any other block with the same normalized name
-        const conflictingBlock = Object.entries(currentBlocks).find(([blockId, block]) => {
-          return (
-            blockId !== id && // Different block
-            block.name && // Has a name
-            normalizeName(block.name) === normalizedNewName // Same normalized name
-          )
-        })
+        if (!normalizedNewName) {
+          logger.error(`Cannot rename block to empty name`)
+          return { success: false, changedSubblocks: [] }
+        }
+
+        const currentBlocks = get().blocks
+        const conflictingBlock = Object.entries(currentBlocks).find(
+          ([blockId, block]) => blockId !== id && normalizeName(block.name) === normalizedNewName
+        )
 
         if (conflictingBlock) {
-          // Don't allow the rename - another block already uses this normalized name
           logger.error(
-            `Cannot rename block to "${name}" - another block "${conflictingBlock[1].name}" already uses the normalized name "${normalizedNewName}"`
+            `Cannot rename block to "${name}" - conflicts with "${conflictingBlock[1].name}"`
           )
           return { success: false, changedSubblocks: [] }
         }
@@ -723,8 +721,8 @@ export const useWorkflowStore = create<WorkflowStore>()(
 
             // Loop through subblocks and update references
             Object.entries(blockValues).forEach(([subBlockId, value]) => {
-              const oldBlockName = oldBlock.name.replace(/\s+/g, '').toLowerCase()
-              const newBlockName = name.replace(/\s+/g, '').toLowerCase()
+              const oldBlockName = normalizeName(oldBlock.name)
+              const newBlockName = normalizeName(name)
               const regex = new RegExp(`<${oldBlockName}\\.`, 'g')
 
               // Use a recursive function to handle all object types
diff --git a/apps/sim/stores/workflows/yaml/importer.ts b/apps/sim/stores/workflows/yaml/importer.ts
index dc2a6b5fd..fe9260a15 100644
--- a/apps/sim/stores/workflows/yaml/importer.ts
+++ b/apps/sim/stores/workflows/yaml/importer.ts
@@ -2,6 +2,7 @@ import { load as yamlParse } from 'js-yaml'
 import { v4 as uuidv4 } from 'uuid'
 import { createLogger } from '@/lib/logs/console/logger'
 import { getBlock } from '@/blocks'
+import { normalizeName } from '@/executor/constants'
 import {
   type ConnectionsFormat,
   expandConditionInputs,
@@ -172,6 +173,34 @@ function validateBlockTypes(yamlWorkflow: YamlWorkflow): { errors: string[]; war
   return { errors, warnings }
 }
 
+/**
+ * Validates block names are non-empty and unique (by normalized name).
+ */
+function validateBlockNames(blocks: Record<string, YamlBlock>): string[] {
+  const errors: string[] = []
+  const seen = new Map<string, string>()
+
+  for (const [blockId, block] of Object.entries(blocks)) {
+    const normalized = normalizeName(block.name)
+
+    if (!normalized) {
+      errors.push(`Block "${blockId}" has empty name`)
+      continue
+    }
+
+    const existingBlockId = seen.get(normalized)
+    if (existingBlockId) {
+      errors.push(
+        `Block "${blockId}" has same name as "${existingBlockId}" (normalized: "${normalized}")`
+      )
+    } else {
+      seen.set(normalized, blockId)
+    }
+  }
+
+  return errors
+}
+
 /**
  * Calculate positions for blocks based on their connections
  * Uses a simple layered approach similar to the auto-layout algorithm
@@ -334,18 +363,19 @@ export function convertYamlToWorkflow(yamlWorkflow: YamlWorkflow): ImportResult
   errors.push(...typeErrors)
   warnings.push(...typeWarnings)
 
+  // Validate block names (non-empty and unique)
+  const nameErrors = validateBlockNames(yamlWorkflow.blocks)
+  errors.push(...nameErrors)
+
   if (errors.length > 0) {
     return { blocks: [], edges: [], errors, warnings }
   }
 
-  // Calculate positions
   const positions = calculateBlockPositions(yamlWorkflow)
 
-  // Convert blocks
   Object.entries(yamlWorkflow.blocks).forEach(([blockId, yamlBlock]) => {
     const position = positions[blockId] || { x: 100, y: 100 }
 
-    // Expand condition inputs from clean format to internal format
     const processedInputs =
       yamlBlock.type === 'condition'
         ? expandConditionInputs(blockId, yamlBlock.inputs || {})
diff --git a/apps/sim/stores/workflows/yaml/parsing-utils.ts b/apps/sim/stores/workflows/yaml/parsing-utils.ts
index db97b0cee..a88e406e6 100644
--- a/apps/sim/stores/workflows/yaml/parsing-utils.ts
+++ b/apps/sim/stores/workflows/yaml/parsing-utils.ts
@@ -1,5 +1,6 @@
 import { v4 as uuidv4 } from 'uuid'
 import { createLogger } from '@/lib/logs/console/logger'
+import { EDGE } from '@/executor/constants'
 
 const logger = createLogger('YamlParsingUtils')
 
@@ -110,7 +111,7 @@ export function generateBlockConnections(
       successTargets.push(edge.target)
     } else if (handle === 'error') {
       errorTargets.push(edge.target)
-    } else if (handle.startsWith('condition-')) {
+    } else if (handle.startsWith(EDGE.CONDITION_PREFIX)) {
       const rawConditionId = extractConditionId(handle)
       rawConditionIds.push(rawConditionId)
 
@@ -671,22 +672,22 @@ function createConditionHandle(blockId: string, conditionId: string, blockType?:
   if (blockType === 'condition') {
     // Map semantic condition IDs to the internal format the system expects
     const actualConditionId = `${blockId}-${conditionId}`
-    return `condition-${actualConditionId}`
+    return `${EDGE.CONDITION_PREFIX}${actualConditionId}`
   }
   // For other blocks that might have conditions, use a more explicit format
-  return `condition-${blockId}-${conditionId}`
+  return `${EDGE.CONDITION_PREFIX}${blockId}-${conditionId}`
 }
 
 function extractConditionId(sourceHandle: string): string {
   // Extract condition ID from handle like "condition-blockId-semantic-key"
   // Example: "condition-e23e6318-bcdc-4572-a76b-5015e3950121-else-if-1752111795510"
 
-  if (!sourceHandle.startsWith('condition-')) {
+  if (!sourceHandle.startsWith(EDGE.CONDITION_PREFIX)) {
     return sourceHandle
   }
 
-  // Remove "condition-" prefix
-  const withoutPrefix = sourceHandle.substring('condition-'.length)
+  // Remove condition prefix
+  const withoutPrefix = sourceHandle.substring(EDGE.CONDITION_PREFIX.length)
 
   // Special case: check if this ends with "-else" (the auto-added else condition)
   if (withoutPrefix.endsWith('-else')) {
diff --git a/apps/sim/tools/index.ts b/apps/sim/tools/index.ts
index b4898a686..930e4e189 100644
--- a/apps/sim/tools/index.ts
+++ b/apps/sim/tools/index.ts
@@ -3,6 +3,7 @@ import { generateRequestId } from '@/lib/core/utils/request'
 import { getBaseUrl } from '@/lib/core/utils/urls'
 import { createLogger } from '@/lib/logs/console/logger'
 import { parseMcpToolId } from '@/lib/mcp/utils'
+import { isCustomTool, isMcpTool } from '@/executor/constants'
 import type { ExecutionContext } from '@/executor/types'
 import type { ErrorInfo } from '@/tools/error-extractors'
 import { extractErrorMessage } from '@/tools/error-extractors'
@@ -210,13 +211,13 @@ export async function executeTool(
     const normalizedToolId = normalizeToolId(toolId)
 
     // If it's a custom tool, use the async version with workflowId
-    if (normalizedToolId.startsWith('custom_')) {
+    if (isCustomTool(normalizedToolId)) {
       const workflowId = params._context?.workflowId
       tool = await getToolAsync(normalizedToolId, workflowId)
       if (!tool) {
         logger.error(`[${requestId}] Custom tool not found: ${normalizedToolId}`)
       }
-    } else if (normalizedToolId.startsWith('mcp-')) {
+    } else if (isMcpTool(normalizedToolId)) {
       return await executeMcpTool(
         normalizedToolId,
         params,
@@ -615,7 +616,7 @@ async function handleInternalRequest(
 
     const fullUrl = fullUrlObj.toString()
 
-    if (toolId.startsWith('custom_') && tool.request.body) {
+    if (isCustomTool(toolId) && tool.request.body) {
       const requestBody = tool.request.body(params)
       if (
         typeof requestBody === 'object' &&
diff --git a/apps/sim/tools/reddit/get_comments.ts b/apps/sim/tools/reddit/get_comments.ts
index 045029318..63cf66277 100644
--- a/apps/sim/tools/reddit/get_comments.ts
+++ b/apps/sim/tools/reddit/get_comments.ts
@@ -1,4 +1,5 @@
 import type { RedditCommentsParams, RedditCommentsResponse } from '@/tools/reddit/types'
+import { normalizeSubreddit } from '@/tools/reddit/utils'
 import type { ToolConfig } from '@/tools/types'
 
 export const getCommentsTool: ToolConfig<RedditCommentsParams, RedditCommentsResponse> = {
@@ -108,8 +109,7 @@ export const getCommentsTool: ToolConfig<RedditCommentsParams, RedditCommentsRes
 
   request: {
     url: (params: RedditCommentsParams) => {
-      // Sanitize inputs
-      const subreddit = params.subreddit.trim().replace(/^r\//, '')
+      const subreddit = normalizeSubreddit(params.subreddit)
       const sort = params.sort || 'confidence'
       const limit = Math.min(Math.max(1, params.limit || 50), 100)
 
diff --git a/apps/sim/tools/reddit/get_controversial.ts b/apps/sim/tools/reddit/get_controversial.ts
index 9e69b37e9..8729fad64 100644
--- a/apps/sim/tools/reddit/get_controversial.ts
+++ b/apps/sim/tools/reddit/get_controversial.ts
@@ -1,4 +1,5 @@
 import type { RedditControversialParams, RedditPostsResponse } from '@/tools/reddit/types'
+import { normalizeSubreddit } from '@/tools/reddit/utils'
 import type { ToolConfig } from '@/tools/types'
 
 export const getControversialTool: ToolConfig<RedditControversialParams, RedditPostsResponse> = {
@@ -72,8 +73,7 @@ export const getControversialTool: ToolConfig<RedditControversialParams, RedditP
 
   request: {
     url: (params: RedditControversialParams) => {
-      // Sanitize inputs
-      const subreddit = params.subreddit.trim().replace(/^r\//, '')
+      const subreddit = normalizeSubreddit(params.subreddit)
       const limit = Math.min(Math.max(1, params.limit || 10), 100)
 
       // Build URL with appropriate parameters using OAuth endpoint
diff --git a/apps/sim/tools/reddit/get_posts.ts b/apps/sim/tools/reddit/get_posts.ts
index bece117bb..36179b741 100644
--- a/apps/sim/tools/reddit/get_posts.ts
+++ b/apps/sim/tools/reddit/get_posts.ts
@@ -1,4 +1,5 @@
 import type { RedditPostsParams, RedditPostsResponse } from '@/tools/reddit/types'
+import { normalizeSubreddit } from '@/tools/reddit/utils'
 import type { ToolConfig } from '@/tools/types'
 
 export const getPostsTool: ToolConfig<RedditPostsParams, RedditPostsResponse> = {
@@ -78,8 +79,7 @@ export const getPostsTool: ToolConfig<RedditPostsParams, RedditPostsResponse> =
 
   request: {
     url: (params: RedditPostsParams) => {
-      // Sanitize inputs
-      const subreddit = params.subreddit.trim().replace(/^r\//, '')
+      const subreddit = normalizeSubreddit(params.subreddit)
       const sort = params.sort || 'hot'
       const limit = Math.min(Math.max(1, params.limit || 10), 100)
 
diff --git a/apps/sim/tools/reddit/hot_posts.ts b/apps/sim/tools/reddit/hot_posts.ts
index 9465f2739..79e27248a 100644
--- a/apps/sim/tools/reddit/hot_posts.ts
+++ b/apps/sim/tools/reddit/hot_posts.ts
@@ -1,4 +1,5 @@
 import type { RedditHotPostsResponse, RedditPost } from '@/tools/reddit/types'
+import { normalizeSubreddit } from '@/tools/reddit/utils'
 import type { ToolConfig } from '@/tools/types'
 
 interface HotPostsParams {
@@ -41,8 +42,7 @@ export const hotPostsTool: ToolConfig<HotPostsParams, RedditHotPostsResponse> =
 
   request: {
     url: (params) => {
-      // Sanitize inputs and enforce limits
-      const subreddit = params.subreddit.trim().replace(/^r\//, '')
+      const subreddit = normalizeSubreddit(params.subreddit)
       const limit = Math.min(Math.max(1, params.limit || 10), 100)
 
       return `https://oauth.reddit.com/r/${subreddit}/hot?limit=${limit}&raw_json=1`
diff --git a/apps/sim/tools/reddit/search.ts b/apps/sim/tools/reddit/search.ts
index f5a53c163..05f6c1361 100644
--- a/apps/sim/tools/reddit/search.ts
+++ b/apps/sim/tools/reddit/search.ts
@@ -1,4 +1,5 @@
 import type { RedditPostsResponse, RedditSearchParams } from '@/tools/reddit/types'
+import { normalizeSubreddit } from '@/tools/reddit/utils'
 import type { ToolConfig } from '@/tools/types'
 
 export const searchTool: ToolConfig<RedditSearchParams, RedditPostsResponse> = {
@@ -85,8 +86,7 @@ export const searchTool: ToolConfig<RedditSearchParams, RedditPostsResponse> = {
 
   request: {
     url: (params: RedditSearchParams) => {
-      // Sanitize inputs
-      const subreddit = params.subreddit.trim().replace(/^r\//, '')
+      const subreddit = normalizeSubreddit(params.subreddit)
       const sort = params.sort || 'relevance'
       const limit = Math.min(Math.max(1, params.limit || 10), 100)
       const restrict_sr = params.restrict_sr !== false // Default to true
diff --git a/apps/sim/tools/reddit/submit_post.ts b/apps/sim/tools/reddit/submit_post.ts
index 718bb3a03..24cc71f58 100644
--- a/apps/sim/tools/reddit/submit_post.ts
+++ b/apps/sim/tools/reddit/submit_post.ts
@@ -1,4 +1,5 @@
 import type { RedditSubmitParams, RedditWriteResponse } from '@/tools/reddit/types'
+import { normalizeSubreddit } from '@/tools/reddit/utils'
 import type { ToolConfig } from '@/tools/types'
 
 export const submitPostTool: ToolConfig<RedditSubmitParams, RedditWriteResponse> = {
@@ -78,8 +79,7 @@ export const submitPostTool: ToolConfig<RedditSubmitParams, RedditWriteResponse>
       }
     },
     body: (params: RedditSubmitParams) => {
-      // Sanitize subreddit
-      const subreddit = params.subreddit.trim().replace(/^r\//, '')
+      const subreddit = normalizeSubreddit(params.subreddit)
 
       // Build form data
       const formData = new URLSearchParams({
diff --git a/apps/sim/tools/reddit/subscribe.ts b/apps/sim/tools/reddit/subscribe.ts
index c6cad76f6..f15c501fe 100644
--- a/apps/sim/tools/reddit/subscribe.ts
+++ b/apps/sim/tools/reddit/subscribe.ts
@@ -1,4 +1,5 @@
 import type { RedditSubscribeParams, RedditWriteResponse } from '@/tools/reddit/types'
+import { normalizeSubreddit } from '@/tools/reddit/utils'
 import type { ToolConfig } from '@/tools/types'
 
 export const subscribeTool: ToolConfig<RedditSubscribeParams, RedditWriteResponse> = {
@@ -53,8 +54,7 @@ export const subscribeTool: ToolConfig<RedditSubscribeParams, RedditWriteRespons
         throw new Error('action must be "sub" or "unsub"')
       }
 
-      // Sanitize subreddit
-      const subreddit = params.subreddit.trim().replace(/^r\//, '')
+      const subreddit = normalizeSubreddit(params.subreddit)
 
       const formData = new URLSearchParams({
         action: params.action,
diff --git a/apps/sim/tools/reddit/utils.ts b/apps/sim/tools/reddit/utils.ts
new file mode 100644
index 000000000..6a7f9b273
--- /dev/null
+++ b/apps/sim/tools/reddit/utils.ts
@@ -0,0 +1,10 @@
+const SUBREDDIT_PREFIX = /^r\//
+
+/**
+ * Normalizes a subreddit name by removing the 'r/' prefix if present and trimming whitespace.
+ * @param subreddit - The subreddit name to normalize
+ * @returns The normalized subreddit name without the 'r/' prefix
+ */
+export function normalizeSubreddit(subreddit: string): string {
+  return subreddit.trim().replace(SUBREDDIT_PREFIX, '')
+}
diff --git a/apps/sim/tools/utils.ts b/apps/sim/tools/utils.ts
index e24be3778..a5a672b4c 100644
--- a/apps/sim/tools/utils.ts
+++ b/apps/sim/tools/utils.ts
@@ -1,5 +1,6 @@
 import { getBaseUrl } from '@/lib/core/utils/urls'
 import { createLogger } from '@/lib/logs/console/logger'
+import { AGENT, isCustomTool } from '@/executor/constants'
 import { useCustomToolsStore } from '@/stores/custom-tools/store'
 import { useEnvironmentStore } from '@/stores/settings/environment/store'
 import { tools } from '@/tools/registry'
@@ -286,10 +287,10 @@ export function getTool(toolId: string): ToolConfig | undefined {
   if (builtInTool) return builtInTool
 
   // Check if it's a custom tool
-  if (toolId.startsWith('custom_') && typeof window !== 'undefined') {
+  if (isCustomTool(toolId) && typeof window !== 'undefined') {
     // Only try to use the sync version on the client
     const customToolsStore = useCustomToolsStore.getState()
-    const identifier = toolId.replace('custom_', '')
+    const identifier = toolId.slice(AGENT.CUSTOM_TOOL_PREFIX.length)
 
     // Try to find the tool directly by ID first
     let customTool = customToolsStore.getTool(identifier)
@@ -319,7 +320,7 @@ export async function getToolAsync(
   if (builtInTool) return builtInTool
 
   // Check if it's a custom tool
-  if (toolId.startsWith('custom_')) {
+  if (isCustomTool(toolId)) {
     return getCustomTool(toolId, workflowId)
   }