Watchtower

Monitor, inspect, and debug all API traffic between AI coding agents and their APIs — with a real-time web dashboard.

Like Chrome DevTools Network tab, but for Claude Code and Codex CLI.

Why

AI coding agents make dozens of API calls per interaction — streaming messages, token counts, quota checks, subagent spawns — and you can't see any of it. Watchtower sits between your AI agent and its API, captures everything, and gives you a live dashboard to inspect it all.

Works with:

• Claude Code (Anthropic)
• Codex CLI (OpenAI)
• Any OpenAI-compatible client

What you see:

• Every request and response, fully decoded
• SSE stream events in real time
• Agent hierarchy tracking (main agent → subagents → utility calls)
• Token usage, rate limits, and timing
• System prompts, tool definitions, full message history
• Dark and light mode
• All logged to disk as JSON for later analysis

Quick Start

npm install -g watchtower-ai
watchtower-ai

Or clone and run directly:

git clone https://github.com/fahd09/watchtower.git
cd watchtower
npm install
npm start

Then point your AI agent at the proxy:

# Claude Code
ANTHROPIC_BASE_URL=http://localhost:8024 claude

# Codex CLI
OPENAI_BASE_URL=http://localhost:8024 codex

Open http://localhost:8025 — that's it. Both providers share the same proxy port. Requests are auto-detected.

Usage

# Default ports: proxy=8024, dashboard=8025
node intercept.mjs

# Custom ports
node intercept.mjs 9000 9001

Dashboard Tabs

| Tab | What it shows | |-----|--------------| | Overview | Duration, model, status, token counts, rate limits | | Messages | Full conversation history (user/assistant messages) | | Response | Pretty-printed response JSON | | Tools | Tool definitions with searchable parameters and schemas | | Stream | Raw SSE events with expandable payloads | | Headers | Request and response headers | | Rate Limits | Rate limit headers with visual progress bars | | Raw | Complete request/response bodies as JSON |

Request Classification

The proxy automatically classifies each request:

Anthropic:

• messages_stream — Streaming chat (the main interaction)
• messages — Non-streaming chat
• token_count — Token counting
• quota_check — Quota/permission check (max_tokens=1)

OpenAI:

• responses_stream / responses — Responses API (Codex CLI default)
• chat_stream / chat_completion — Chat Completions API
• models — Model listing
• embeddings — Embedding requests

Agent Roles

Each request is tagged with an agent role:

• main — The primary agent (Claude Code's main agent has the Agent tool; Codex requests with tools)
• subagent — A spawned sub-agent (Explore, Plan, etc.)
• utility — Token counts, quota checks, and tool-less calls

Logs

All requests are saved to ./logs/ as numbered JSON files:

logs/0001_messages_stream_claude-opus-4-6.json
logs/0002_token_count_claude-haiku-4-5-20251001.json

Each file contains the complete request/response cycle: headers, body, SSE events, timing, and rate limits.

How It Works

Claude Code  ──HTTP──┐
                     ├──>  Watchtower (proxy)  ──HTTPS──>  api.anthropic.com
Codex CLI    ──HTTP──┘          │              ──HTTPS──>  api.openai.com / chatgpt.com
                                │
                                ├── logs to disk
                                ├── broadcasts via WebSocket
                                │
                          Dashboard (web UI)

1. Your AI agent sends requests to the local proxy instead of directly to the API
2. Watchtower auto-detects the provider and forwards to the correct upstream
3. Responses (including SSE streams) are decoded, logged, and forwarded back
4. The dashboard connects via WebSocket for real-time updates

Requirements

• Node.js >= 18

Roadmap

See TODO.md for the full roadmap, including planned features like:

• Cost & token tracking
• Search & filter
• System prompt diffing
• Request replay & modification (Burp Suite for Claude)
• Agent hierarchy tree visualization

Contributing

Contributions welcome. Open an issue first for anything non-trivial.

git clone https://github.com/fahd09/watchtower.git
cd watchtower
npm install
npm start

The proxy is in intercept.mjs, provider logic in providers/, and the dashboard is a single dashboard.html. No build step, no bundler.

License

MIT