GitHub Actions Retries and REST API Idempotency Keys: Missing Automatic Key Propagation

Integration Gap

When integrating GitHub Actions workflow retries with the REST API's idempotency-key mechanism, the platform does not automatically generate or propagate Idempotency-Key headers across retry attempts. This leaves a gap where transient failures (rate limits, network errors) trigger retries that the API treats as new requests, potentially creating duplicate repositories, issues, or comments. The 24-hour key TTL further complicates long-running workflows that may retry beyond the cache window, and the supported-endpoint list changes without versioned notice.

Open Questions

1. What pattern ensures a stable idempotency key survives Actions retry cycles without external state stores?
2. How should consumers detect when a write endpoint loses idempotency support between API versions?
3. Is there a recommended strategy for coordinating key scope across multiple GitHub App installations targeting the same repository?