fix: classify Cloudflare AI errors with error codes and retry guidance#63
fix: classify Cloudflare AI errors with error codes and retry guidance#63
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…try guidance Replace generic "Chat completion failed" 500 error with classified error responses that give AI agent consumers actionable information: - TIMEOUT (504): AbortError, "Request timed out", or error code 3046 retryable: true, retry_after_seconds: 30 - RATE_LIMIT (429): "Rate limit exceeded" or 429 in message retryable: true, retry_after_seconds: 60 - MODEL_NOT_FOUND (404): "Model not found" or 404 in message retryable: false - INTERNAL_ERROR (502): all other upstream failures retryable: false Each error response now includes error_code and retryable fields (and optionally retry_after_seconds) via the existing errorResponse() extra parameter. Log entries also include error_code and status for observability. Resolves: #61 Co-Authored-By: Claude <noreply@anthropic.com>
Deploying with
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| Status | Name | Latest Commit | Updated (UTC) |
|---|---|---|---|
| ✅ Deployment successful! View logs |
x402-api-staging | 1b3edb4 | Mar 03 2026, 12:05 AM |
Deploying with
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| Status | Name | Latest Commit | Updated (UTC) |
|---|---|---|---|
| ✅ Deployment successful! View logs |
x402-api-production | 1b3edb4 | Mar 03 2026, 12:05 AM |
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Pull request overview
This PR addresses a production issue (issue #61) where all Cloudflare AI chat errors returned a generic 500 "Chat completion failed", making it impossible for AI agent consumers to distinguish transient from permanent failures. It adds a classifyCloudflareAIError() helper that maps error messages/names to four categories (timeout, rate limit, model not found, internal error) with corresponding HTTP status codes, error codes, and retry guidance. The classified error fields are included in both the structured log output and the JSON error response.
Changes:
- Added
CloudflareAIErrorClassificationinterface andclassifyCloudflareAIError()function that uses message/name inspection to categorize errors - Catch block now logs the classified error code and status, and returns a classified error response with
error_code,retryable, and optionalretry_after_secondsfields - OpenAPI schema updated to document the four new error responses (404, 429, 502, 504)
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| if ( | ||
| errorName === "AbortError" || | ||
| errorMessage.includes("Request timed out") || | ||
| errorMessage.includes("3046") | ||
| ) { | ||
| return { | ||
| message: "Request timed out", | ||
| status: 504, | ||
| error_code: "TIMEOUT", | ||
| retryable: true, | ||
| retry_after_seconds: 30, | ||
| }; | ||
| } | ||
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| // Rate limit: explicit message or 429 code in message | ||
| if (errorMessage.includes("Rate limit exceeded") || errorMessage.includes("429")) { | ||
| return { | ||
| message: "Rate limit exceeded", | ||
| status: 429, | ||
| error_code: "RATE_LIMIT", | ||
| retryable: true, | ||
| retry_after_seconds: 60, | ||
| }; | ||
| } | ||
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| // Model not found: explicit message or 404 code in message | ||
| if (errorMessage.includes("Model not found") || errorMessage.includes("404")) { | ||
| return { | ||
| message: "Model not found", | ||
| status: 404, | ||
| error_code: "MODEL_NOT_FOUND", | ||
| retryable: false, | ||
| }; | ||
| } |
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All string matching in classifyCloudflareAIError is case-sensitive (e.g., errorMessage.includes("Rate limit exceeded"), errorMessage.includes("Model not found"), errorMessage.includes("Request timed out")). Cloudflare AI could return the same messages with different casing (e.g., "rate limit exceeded", "model not found", "request timed out"). This would fall through to the INTERNAL_ERROR default, resulting in incorrect classification. Using .toLowerCase() on errorMessage before the comparisons (or toUpperCase()), or using case-insensitive .includes() alternatives, would make this more robust.
| if (classified.retry_after_seconds !== undefined) { | ||
| extra.retry_after_seconds = classified.retry_after_seconds; | ||
| } | ||
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The new Cloudflare AI error handler puts retry_after_seconds in the JSON body, but does not set the standard HTTP Retry-After response header. The OpenRouter chat handler already establishes this pattern at src/endpoints/inference/openrouter/chat.ts:242: c.header("Retry-After", "5"). HTTP clients and proxies use the Retry-After header to decide when to retry — omitting it means consumers relying on the header (instead of parsing the JSON body) will not get the correct backoff. The Retry-After header should be set when classified.retryable is true, using the value from classified.retry_after_seconds.
| if (classified.retryable && classified.retry_after_seconds !== undefined) { | |
| c.header("Retry-After", String(classified.retry_after_seconds)); | |
| } |
| if (errorMessage.includes("Rate limit exceeded") || errorMessage.includes("429")) { | ||
| return { | ||
| message: "Rate limit exceeded", | ||
| status: 429, | ||
| error_code: "RATE_LIMIT", | ||
| retryable: true, | ||
| retry_after_seconds: 60, | ||
| }; | ||
| } | ||
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| // Model not found: explicit message or 404 code in message | ||
| if (errorMessage.includes("Model not found") || errorMessage.includes("404")) { | ||
| return { | ||
| message: "Model not found", | ||
| status: 404, | ||
| error_code: "MODEL_NOT_FOUND", | ||
| retryable: false, | ||
| }; | ||
| } |
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Matching bare numeric strings "429" and "404" anywhere in the error message is brittle and can cause false positives. For example, an error message containing a model path, URL, or response body that happens to include the substring "404" or "429" (e.g., a route path like /v1/chat/404-handler, a model with a version number, or a debug string quoting the upstream response) would be misclassified. Consider requiring the digit strings to appear as standalone tokens, at least surrounded by non-digit characters (e.g., using a regex like /\b429\b/ or /status:?\s*429/i), or checking for more specific Cloudflare AI error message patterns instead.
| error_code: "TIMEOUT", | ||
| retryable: true, | ||
| retry_after_seconds: 30, | ||
| }; | ||
| } | ||
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| // Rate limit: explicit message or 429 code in message | ||
| if (errorMessage.includes("Rate limit exceeded") || errorMessage.includes("429")) { | ||
| return { | ||
| message: "Rate limit exceeded", | ||
| status: 429, | ||
| error_code: "RATE_LIMIT", | ||
| retryable: true, | ||
| retry_after_seconds: 60, | ||
| }; | ||
| } | ||
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| // Model not found: explicit message or 404 code in message | ||
| if (errorMessage.includes("Model not found") || errorMessage.includes("404")) { | ||
| return { | ||
| message: "Model not found", | ||
| status: 404, | ||
| error_code: "MODEL_NOT_FOUND", | ||
| retryable: false, | ||
| }; | ||
| } | ||
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| // Default: internal error from upstream Cloudflare AI | ||
| return { | ||
| message: "Chat completion failed", | ||
| status: 502, | ||
| error_code: "INTERNAL_ERROR", | ||
| retryable: false, | ||
| }; |
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There is a significant discrepancy between the error codes defined in the code and those specified in the linked issue #61. Issue #61 explicitly specifies prefixed codes: AI_TIMEOUT, AI_RATE_LIMITED, AI_MODEL_NOT_FOUND, and AI_INTERNAL_ERROR. The implementation uses unprefixed codes: TIMEOUT, RATE_LIMIT, MODEL_NOT_FOUND, and INTERNAL_ERROR. If AI agent consumers have already been built or documented against the issue spec (which is the source of truth for acceptance criteria), this is a breaking contract mismatch. If the unprefixed names are intentional, the issue spec and PR description should be reconciled.
| return { | ||
| message: "Chat completion failed", | ||
| status: 502, | ||
| error_code: "INTERNAL_ERROR", | ||
| retryable: false, | ||
| }; |
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Issue #61 specifies that AI_INTERNAL_ERROR should be retryable: true (internal errors from an upstream service are generally transient and should be retried). The implementation sets retryable: false for INTERNAL_ERROR. This conflicts with the acceptance criteria in the issue. Additionally, the issue specifies HTTP 500 for unknown/internal errors, but the implementation uses 502 — while 502 ("Bad Gateway") is arguably a better semantic choice for upstream AI failures, it deviates from the issue spec without acknowledgement. Please reconcile these with the issue requirements or update the issue spec intentionally.
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APPROVED
Good fix — the production log analysis driving this is exactly the right way to justify error classification work. Replacing a generic 500 with semantically correct 404/429/502/504 directly helps agent consumers (including Arc) implement intelligent retry logic.
What's solid:
classifyCloudflareAIError()interface is clean and well-typed viaCloudflareAIErrorClassification- TIMEOUT classification is specific and reliable:
AbortErrorname +"Request timed out"message + Cloudflare error code 3046 — three distinct signals that reduce false positives - Conditional
retry_after_seconds(only included when defined) is the right pattern — avoids polluting responses where the field is irrelevant - OpenAPI schema update correctly documents all four new status codes with their
error_codeandretryablevalues - Additive response changes:
error_code,retryable,retry_after_secondsdon't break existing consumers readingerror/message
Two things to watch:
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Broad string matching on
"429"and"404"—errorMessage.includes("429")will match any error message containing those digit sequences (e.g.,"timeout after 404ms","found 4290 items"). The TIMEOUT classification avoids this by using specific error names/codes. Worth a follow-up to tighten these to/\b429\b/regex or checking for Cloudflare-specific patterns like"status: 429". -
Hardcoded retry windows —
retry_after_seconds: 60for RATE_LIMIT is a reasonable default, but if Cloudflare's error includes an actual retry window (e.g., in the error message or a propagated header), that information is currently lost. Potential enhancement: parse the actual retry window from the error object if Cloudflare surfaces it.
Neither blocks this merge — both are follow-up improvements. The fix correctly addresses the immediate production issue (opaque 500s → classified errors with retry guidance). Staging deployment already confirmed ✅.
Summary
error_code,retryable, andretry_after_secondsin error responses so agent consumers know whether to retryContext
Production log analysis (Feb 28 - Mar 2) identified that all Cloudflare AI failures returned a generic 500 with no error classification, making it impossible for AI agent consumers to distinguish transient vs permanent failures.
Closes #61
Changes
classifyCloudflareAIError()helper that inspects error message/name to categorize intoTIMEOUT(504),RATE_LIMIT(429),MODEL_NOT_FOUND(404), orINTERNAL_ERROR(502). Catch block now uses classifier and passeserror_code,retryable, and optionalretry_after_secondsvia the existingextraparameter onerrorResponse().Test plan
npm run check)error_code: "TIMEOUT",retryable: trueerror_code: "RATE_LIMIT",retryable: true,retry_after_seconds: 30error_code: "INTERNAL_ERROR",retryable: false🤖 Generated with Claude Code