Bug: trace logger truncates long field values #19

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opened 2026-04-08 21:15:56 +00:00 by claude-code · 0 comments

claude-code commented

2026-04-08 21:15:56 +00:00

Collaborator

Discovered during M2.3 smoke test (trace 1a8711c4-a65b-49fd-853e-50fde79c755f, step 23).

The synthesis_error step's raw_response field contains the full LLM JSON output, which is essential for debugging the parse failure (see Issue #16). But in the trace JSONL the value is cut off mid-word ("butterhe" — clearly truncated from "butterhead"), losing the part of the response that would actually pinpoint the parse error.

Repro

Same trace as Issue #16 — inspect step 23 in ~/.marchwarden/traces/1a8711c4-a65b-49fd-853e-50fde79c755f.jsonl directly with jq to confirm the truncation is in the file itself, not just the renderer.

Suggested fix

If truncation is intentional, raise the cap (or remove it for debug-relevant fields like raw_response)
Long fields should be either fully captured or split across continuation entries — partial JSON is worse than no JSON
Verify whether TraceLogger.log_step or the agent's call site is doing the truncation

Discovered during M2.3 smoke test (trace `1a8711c4-a65b-49fd-853e-50fde79c755f`, step 23). The `synthesis_error` step's `raw_response` field contains the full LLM JSON output, which is essential for debugging the parse failure (see Issue #16). But in the trace JSONL the value is cut off mid-word ("butterhe" — clearly truncated from "butterhead"), losing the part of the response that would actually pinpoint the parse error. ## Repro Same trace as Issue #16 — inspect step 23 in `~/.marchwarden/traces/1a8711c4-a65b-49fd-853e-50fde79c755f.jsonl` directly with `jq` to confirm the truncation is in the file itself, not just the renderer. ## Suggested fix - If truncation is intentional, raise the cap (or remove it for debug-relevant fields like `raw_response`) - Long fields should be either fully captured or split across continuation entries — partial JSON is worse than no JSON - Verify whether `TraceLogger.log_step` or the agent's call site is doing the truncation