fix: prevent infinite retry loop for images exceeding 5MB

- Change MAX_IMAGE_BYTES from 6MB to 5MB to match Anthropic API limit
- Add isImageSizeError() to detect image size errors from API
- Handle image size errors with user-friendly message instead of retry
- Prevent failover for image size errors (not retriable)

Fixes #2271

src/agents/pi-embedded-helpers.ts

@@ -23,6 +23,7 @@ export {
   isFailoverAssistantError,
   isFailoverErrorMessage,
   isImageDimensionErrorMessage,
+  isImageSizeError,
   isOverloadedErrorMessage,
   isRawApiErrorPayload,
   isRateLimitAssistantError,

src/agents/pi-embedded-helpers/errors.ts

@@ -467,6 +467,12 @@ export function isImageDimensionErrorMessage(raw: string): boolean {
   return Boolean(parseImageDimensionError(raw));
 }
 
+export function isImageSizeError(errorMessage?: string): boolean {
+  if (!errorMessage) return false;
+  const lower = errorMessage.toLowerCase();
+  return lower.includes("image exceeds") && lower.includes("mb");
+}
+
 export function isCloudCodeAssistFormatError(raw: string): boolean {
   return !isImageDimensionErrorMessage(raw) && matchesErrorPatterns(raw, ERROR_PATTERNS.format);
 }
@@ -478,6 +484,7 @@ export function isAuthAssistantError(msg: AssistantMessage | undefined): boolean
 
 export function classifyFailoverReason(raw: string): FailoverReason | null {
   if (isImageDimensionErrorMessage(raw)) return null;
+  if (isImageSizeError(raw)) return null;
   if (isRateLimitErrorMessage(raw)) return "rate_limit";
   if (isOverloadedErrorMessage(raw)) return "rate_limit";
   if (isCloudCodeAssistFormatError(raw)) return "format";

src/agents/pi-embedded-runner/run.ts

@@ -34,6 +34,7 @@ import {
   isContextOverflowError,
   isFailoverAssistantError,
   isFailoverErrorMessage,
+  isImageSizeError,
   parseImageDimensionError,
   isRateLimitAssistantError,
   isTimeoutErrorMessage,
@@ -440,6 +441,29 @@ export async function runEmbeddedPiAgent(
                 },
               };
             }
+            // Handle image size errors with a user-friendly message (no retry needed)
+            if (isImageSizeError(errorText)) {
+              return {
+                payloads: [
+                  {
+                    text:
+                      "Image too large for the model (max 5MB). " +
+                      "Please compress or resize the image and try again.",
+                    isError: true,
+                  },
+                ],
+                meta: {
+                  durationMs: Date.now() - started,
+                  agentMeta: {
+                    sessionId: sessionIdUsed,
+                    provider,
+                    model: model.id,
+                  },
+                  systemPromptReport: attempt.systemPromptReport,
+                  error: { kind: "image_size", message: errorText },
+                },
+              };
+            }
             const promptFailoverReason = classifyFailoverReason(errorText);
             if (promptFailoverReason && promptFailoverReason !== "timeout" && lastProfileId) {
               await markAuthProfileFailure({

src/agents/pi-embedded-runner/types.ts

@@ -20,7 +20,7 @@ export type EmbeddedPiRunMeta = {
   aborted?: boolean;
   systemPromptReport?: SessionSystemPromptReport;
   error?: {
-    kind: "context_overflow" | "compaction_failure" | "role_ordering";
+    kind: "context_overflow" | "compaction_failure" | "role_ordering" | "image_size";
     message: string;
   };
   /** Stop reason for the agent run (e.g., "completed", "tool_calls"). */

src/media/constants.ts

@@ -1,4 +1,4 @@
-export const MAX_IMAGE_BYTES = 6 * 1024 * 1024; // 6MB
+export const MAX_IMAGE_BYTES = 5 * 1024 * 1024; // 5MB (Anthropic API limit)
 export const MAX_AUDIO_BYTES = 16 * 1024 * 1024; // 16MB
 export const MAX_VIDEO_BYTES = 16 * 1024 * 1024; // 16MB
 export const MAX_DOCUMENT_BYTES = 100 * 1024 * 1024; // 100MB