[pavelgj]

Fixes #5270
Fixes #5331

What

Make the retry middleware to respect the Retry-After HTTP header from providers, and prevents retrying errors that should never be retried.

Changes

Core (@genkit-ai/core)

• Added ErrorResponseMetadata interface with retryAfterMs and headers fields
• Added optional responseMetadata property to GenkitError (not serialized in toJSON() — in-process only)

Retry middleware (@genkit-ai/middleware)

• Uses responseMetadata.retryAfterMs as a floor for the retry delay (Math.max(computedDelay, retryAfterMs))
• Never retries AbortError (from AbortController) or ToolInterruptError (control-flow signal), regardless of error type
• Added 4 new unit tests covering both behaviors

Provider plugins — all now capture Retry-After from HTTP responses and pass it as responseMetadata on GenkitError:

• google-genai: googleai/client.ts and vertexai/client.ts read from Response.headers
• compat-oai: reads from OpenAI SDK APIError.headers
• anthropic: added try/catch around runner.run() to convert Anthropic SDK APIError → GenkitError with status mapping (429→RESOURCE_EXHAUSTED, 401→UNAUTHENTICATED, etc.) and Retry-After propagation

Notes

• parseRetryAfterMs supports both delay-seconds and HTTP-date formats (RFC 7231 §7.1.3), with guards against empty/whitespace input
• retryAfterMs uses !== undefined checks to preserve Retry-After: 0 as a valid "retry immediately" signal
• The anthropic plugin previously let raw SDK errors propagate; it now normalizes them to GenkitError with proper status codes

[gemini-code-assist]

Code Review

This pull request introduces ErrorResponseMetadata to GenkitError, enabling the capture of HTTP response details such as Retry-After headers. This allows the retry middleware to honor provider-suggested delays and includes a new blacklist for errors that should never be retried, specifically AbortError and ToolInterruptError. Feedback focuses on improving the robustness of the Retry-After parsing logic to handle whitespace and zero-value delays, ensuring the error blacklist is applied consistently across all error types, and adding null-safety checks when accessing error properties.

[pavelgj]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a mechanism to honor the Retry-After HTTP header from various model providers (Anthropic, OpenAI, and Google GenAI) by capturing it in a new responseMetadata field within GenkitError. The retry middleware has been updated to use this metadata as a minimum delay floor and to explicitly avoid retrying specific errors such as AbortError and ToolInterruptError. I have no feedback to provide.