Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add instructions/pydantic/claude-code-logfire-plugin/claude-mdgit clone --depth 1 https://github.com/pydantic/claude-code-logfire-pluginWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00995 | $0.00995 |
| Opus 5 | $0.00498 | $0.00498 |
| Sonnet 5 | $0.00199 | $0.00199 |
| Haiku 4.5 | $0.00100 | $0.00100 |
Grade A, and why
claude-code-logfire-plugin CLAUDE.md scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
**Data flow:** Claude Code hook fires -> stdin JSON piped to `log-event.py` -> appends JSONL locally -> if `LOGFIRE_TOKEN` set and event is SessionStart/Stop/SubagentStop/SessionEnd, builds OTLP/HTTP JSON payload and sen How it starts
The opening of the file, as written. The whole thing — 67 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
What This Is
A Claude Code plugin that captures sessions and exports pydantic-ai compatible OTel traces to Pydantic Logfire, with local JSONL fallback. The plugin is a single Python 3 script (stdlib only, no external dependencies).
Architecture
The entire plugin is a single Python script (scripts/log-event.py) invoked by every hook event defined in hooks/hooks.json. The plugin manifest lives at .claude-plugin/plugin.json.
Data flow: Claude Code hook fires -> stdin JSON piped to log-event.py -> appends JSONL locally -> if LOGFIRE_TOKEN set and event is SessionStart/Stop/SubagentStop/SessionEnd, builds OTLP/HTTP JSON payload and sends via urllib.
Session state: A temp file ($TMPDIR/claude-logfire-{session_id}.json) persists the root span ID, start time, transcript line offset, accumulated messages, usage totals, and cost details between hook invocations. Created on SessionStart, deleted on SessionEnd.
Trace correlation: trace_id is deterministically derived from session_id via SHA-256.
Span hierarchy (pydantic-ai style):
agent run (root span) <- the session (emitted on SessionEnd)
├── chat claude-opus-4-6 <- LLM API call 1 (emitted on Stop)
├── chat claude-opus-4-6 <- LLM API call 2 (emitted on Stop)
└── chat claude-opus-4-6 <- LLM API call 3 (emitted on Stop)
OTLP processing model:
| Hook Event | JSONL | OTLP |
|---|---|---|
| SessionStart | yes | pending root span (logfire.span_type=pending_span) |
| Stop / SubagentStop | yes | "chat {model}" child spans per LLM API call |
| SessionEnd | yes | finalized root "agent run" span with all_messages, usage, cost |
| All other events | yes | none (early exit) |
Transcript parsing: On Stop events, the script reads new transcript lines (since last offset), deduplicates streaming fragments by message.id, identifies API call boundaries, and converts messages to pydantic-ai format (tool_use -> tool_call, tool_result -> tool_call_response, end_turn -> stop).
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 67 lines · 995 tokens per session scan A 17a458a60200
claude-code-logfire-plugin CLAUDE.md is an instructions file published in the GitHub repository pydantic/claude-code-logfire-plugin (15 stars, last pushed 2mo ago), licensed MIT. It adds 995 tokens to every session, about $0.0050 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).
next.js AGENTS.md
Instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.