Your coding agent bundles system prompts, tool schemas and entire conversation histories into every model call — and you never see any of it. context-tracker gives you X-ray vision into that hidden payload.
A zero-dependency local proxy + viewer that mirrors every request from Claude Code, Codex and OpenCode — without touching the live request path. Inspect it. Search it. Understand your token spend at the source.
When Claude Code or Codex feels slow, expensive, or "off," the truth is buried in an HTTPS request you can't read. Prompts balloon, tool definitions pile up, conversation history never gets trimmed — invisibly.
Point your agent's base URL at the local proxy. It forwards traffic to the real API untouched — streaming responses pass straight through — while mirroring a copy of each request to the viewer. Fire-and-forget: it never blocks or alters your agent.
Claude Code ──ANTHROPIC_BASE_URL──▶ ┐ Codex CLI ──config.toml base_url─▶ ├─▶ proxy ──HTTPS──▶ AI API OpenCode ──opencode.json baseURL▶ ┘ │ └──POST──▶ viewer (:39877)
Everything runs locally with zero runtime dependencies — just Node.
Normalizes Anthropic Messages, OpenAI Chat & Responses into one clean view: system, tools, message turns.
Incremental polling fetches only new/updated entries. Poll cost stays constant whether you have 10 requests or 10,000.
Only viewport rows are rendered. Thousands of captured requests, still just a few dozen DOM nodes. No jank.
Live search across path, model and content with highlighting. Filter by source and API with stackable chips.
Route one proxy port to several providers by path prefix — capture Claude and Codex at the same time.
Preset providers in config/profiles.json and launch by name. No more retyping target URLs.
Optionally tee and reassemble streaming SSE responses, correlated back to their originating request.
One flag redacts API keys in both terminal and web output. Your secrets stay yours.
Pure Node built-ins. Nothing to audit, nothing to update, nothing to break.
# global CLI, zero deps
npm install -g context-tracker
context-tracker viewer # web UI at http://localhost:39877
context-tracker proxy anthropic # or: openai, deepseek, claude+codex
export ANTHROPIC_BASE_URL=http://localhost:39876 claude # every request now appears live in the viewer
| API | Path | Source tool |
|---|---|---|
| Anthropic Messages | /v1/messages | Claude Code |
| OpenAI Responses | /v1/responses | Codex |
| OpenAI Chat Completions | /v1/chat/completions | OpenCode / DeepSeek / … |
Works with any header-authenticated provider — Anthropic, OpenAI, DeepSeek, OpenRouter and more.