Bazel action key changed unexpectedly
At least one key-forming property differs between the two actions. The output may be logically equivalent, but Bazel cannot reuse it when the action key differs.
Common causes
- A declared input or tool digest changed
- Command arguments or feature expansion changed
- Environment or workspace-status data changed
- Execution-platform or toolchain properties changed
What to check
- Compare the two execution-log action records
- Start with command, environment, platform, and tool inputs
- Trace the first changed input to its generating action
- Remove volatile or host-specific data only when doing so preserves correctness
Primary sources
Use these references to confirm protocol and version-specific behavior.
Investigate with build-level evidence
Hermetiq correlates Bazel actions, cache behavior, Buildbarn infrastructure, and remote-execution timing so teams can move from a status code to the build and system behavior behind it.
Technical review: July 20, 2026 · Verify flags and behavior against the Bazel and Buildbarn versions deployed in your environment.