# Langsmith Fetch

> Fetches LangSmith traces for debugging agent behavior. Use when troubleshooting agent issues, reviewing conversation history, or investigating tool calls.

- Skill: `langchain-ai/langsmith-fetch` (Agent Skill)
- Install (CLI): `npx skillmds@latest add langchain-ai/langsmith-fetch`
- Raw SKILL.md: https://api.skillmd.com/api/skills/langchain-ai/langsmith-fetch/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: langchain-ai (https://skillmd.com/u/langchain-ai)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/langchain-ai/langsmith-fetch

---


# Fetching LangSmith Traces

Requires `langsmith-fetch` in project dependencies and `LANGSMITH_API_KEY` in a `.env` file.

## Setup

First, find the `.env` file containing `LANGSMITH_API_KEY`:
```bash
find . -name ".env" -type f 2>/dev/null | head -5
```

## Commands

Use `--env-file <path-to-.env>` with all commands:

```bash
# 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

# Fetch single trace by ID
uv run --env-file <path> langsmith-fetch trace <trace-id>

# Include metadata (timing, tokens, costs)
uv run --env-file <path> langsmith-fetch trace <trace-id> --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?