Requires langsmith-fetch in project dependencies and LANGSMITH_API_KEY in a .env file.
Setup
First, find the .env file containing LANGSMITH_API_KEY:
find . -name ".env" -type f 2>/dev/null | head -5
Commands
Use --env-file <path-to-.env> with all commands:
# Fetch recent traces (uses LANGSMITH_PROJECT from .env, or specify --project-uuid)
uv run --env-file <path> langsmith-fetch traces ./traces --limit 10
uv run --env-file <path> langsmith-fetch traces ./traces --project-uuid <uuid> --limit 10
uv run --env-file langsmith-fetch trace
Include metadata (timing, tokens, costs)uv run --env-file langsmith-fetch trace --include-metadata
## Output Formats
- `--format pretty` - Human-readable (default)
- `--format json` - Pretty-printed JSON
- `--format raw` - Compact JSON for piping
## Troubleshooting Workflow
1. Find `.env`: `find . -name ".env" -type f 2>/dev/null`
2. Fetch recent traces: `uv run --env-file <path> langsmith-fetch traces ./debug --limit 10`
3. Find relevant trace in saved JSON files
4. Check: What tools were called? What did they return? Was it correct/expected?