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feat(hook): accept caller trace tags via CC_LANGFUSE_TRACE_TAGS - #87
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hassiebp merged 2 commits intoSep 9, 2026
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…de-the-hook-operator-tags
This was referenced Oct 15, 2026
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What
CC_LANGFUSE_TRACE_TAGSadds a caller's own tags to every trace, next toclaude-codeand theskill:*tags. The value is either a JSON array (["lane:review","env:prod"]) or a comma-separated list (lane:review,env:prod).Blank and duplicate entries are dropped; entries over 200 characters, and anything past the first 20, are dropped with a log line.
Refs #62 and the tag half of #69. Neither is closed by this PR — see the two notes below.
Why one variable serves both issues
#69 asks for a JSON array. #62 asks for a comma-separated list and argues for tags over metadata. The reference both issues point at, the sibling
codex-observability-plugin, already accepts both shapes in one variable: it parses JSON when the value starts with[and falls back to comma splitting. This PR does the same.Two decisions a reviewer should confirm
Tags only. The metadata half of #69 is left out on purpose. Measured against the live API:
?tags=lane:reviewfilters correctly, while?metadata={"lane":"review"}is silently ignored and returns unfiltered results.Verification
End to end against a live Langfuse, same transcript and same environment variable in each run, only the hook differs:
CC_LANGFUSE_TRACE_TAGSmain["lane:review","env:prod"]['claude-code']["lane:review","env:prod"]['claude-code', 'env:prod', 'lane:review']lane:executor,env:staging['claude-code', 'env:staging', 'lane:executor']{"lane":"review"}['claude-code'], with a diagnosticThe before run had the variable set as well; the old hook simply does not read it. In every run the trace still exported, including the rejected one, so telemetry stays best-effort.
The lane use case from #69, checked server-side:
?tags=lane:review,?tags=lane:executorand?tags=lane:scheduledeach return only their own session, and?tags=env:prodreturns all of them. No use of the deploymentenvironmentfield.Tests: 247 pass, up from 228. All 19 new tests fail without the change.
Linear: LFE-16088