AgentTap

Capture your AI agent traces at the network level — transparently, locally, and without per-app configuration.

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AgentTap is a macOS desktop app that intercepts AI provider API traffic through a local MITM proxy using DNS-based routing, capturing complete request/response traces in real time. No JSONL scraping, no fragile file watchers — just raw API data captured at the network layer.

Why?

Current approaches to capturing AI agent conversations are fragile:

• JSONL file parsing depends on each tool's local logging format — one update breaks everything
• Manual certificate swapping requires sudo commands and disrupts all your traffic
• Per-app proxy config (HTTPS_PROXY, NODE_EXTRA_CA_CERTS) needs setup for every tool individually

AgentTap solves this with DNS-based interception: only AI provider domains are routed through a local transparent proxy via /etc/hosts and pf redirect rules. Everything else is unaffected. Turn it on, and every API call to Anthropic, OpenAI, Google AI, etc. is captured — whether it comes from Claude Code, Cursor, Codex, or any other agent.

Installation

brew install --cask GeiserX/agenttap/agenttap

On first launch, AgentTap will prompt for admin access to install a privileged helper that manages firewall rules and CA certificate trust. This is a one-time setup.

How It Works

AI coding agent (Claude Code, Cursor, Codex, etc.)
    |
    v
[/etc/hosts redirects AI domains to 127.0.0.1]
    |
    v
[pf rdr routes to local transparent proxy]
    |
    v
[MITM proxy — decrypts, captures, re-encrypts]
    |
    v
[Upstream forwarder — resolves real IP via DoH, connects directly]
    |
    v
[Response captured to SQLite and relayed back]

All other traffic (browsing, Slack, email, etc.) flows normally — only configured AI provider domains are intercepted.

Features

• Zero per-app configuration — works at the network level; any tool that calls an AI API is captured automatically
• Selective domain routing — only AI API domains are intercepted; everything else untouched
• Real-time streaming capture — captures SSE streams as they happen, not after the fact
• Cost estimation — per-trace cost calculated from model and token counts
• Session grouping — traces grouped by time window for easy browsing
• Multi-provider support — 10 providers out of the box, with more easily added
• Export — download traces as JSON, JSONL, or cURL commands
• Filtering — filter traces by provider, model, or source application
• Menu bar app — tray icon with live status (closed eye = off, open eye = capturing, X eye = error)
• Local-only storage — traces stored in SQLite on your machine; nothing leaves your network

Supported Providers

Provider	Domains
Anthropic	api.anthropic.com
OpenAI	api.openai.com
Google AI	generativelanguage.googleapis.com
AWS Bedrock	bedrock-runtime.{us-east-1,us-west-2,eu-west-1}.amazonaws.com
Mistral	api.mistral.ai
DeepSeek	api.deepseek.com
xAI	api.x.ai
Cohere	api.cohere.ai
Groq	api.groq.com
Cursor	api2.cursor.sh

More providers can be added via configuration.

Architecture

┌─────────────────────────────────────────────────┐
│  ElectroBun Desktop App (menu bar)              │
│  Toggle capture, browse traces, export data     │
├─────────────────────────────────────────────────┤
│  Privileged Helper (LaunchDaemon)               │
│  pf rules, /etc/hosts, CA keychain trust        │
├────────────┬────────────────────────────────────┤
│ Transparent│  MITM Proxy        │ Upstream      │
│ Proxy      │  TLS termination,  │ Forwarder     │
│ (CONNECT)  │  request/response  │ (DoH resolve, │
│            │  capture, SSE      │  direct conn)  │
│            │  reassembly        │               │
├────────────┴────────────────────┴───────────────┤
│  SQLite Storage + Write Batcher                 │
│  Traces, sessions, cost data                    │
└─────────────────────────────────────────────────┘

• Privileged Helper — a Swift LaunchDaemon that manages pf firewall rules, /etc/hosts entries, and system keychain CA trust via a Unix socket protocol
• Transparent Proxy — accepts redirected connections and establishes CONNECT tunnels to the MITM proxy
• MITM Proxy — per-domain TLS termination with dynamically generated leaf certificates, full request/response capture, chunked transfer and SSE stream reassembly
• Upstream Forwarder — resolves real provider IPs via DNS-over-HTTPS (bypassing local /etc/hosts overrides), then connects directly with connection pooling
• CA Trust — auto-generated root CA persisted in ~/Library/Application Support/AgentTap/ca/, trusted in macOS keychain and exported via NODE_EXTRA_CA_CERTS for Bun/Node.js tools

Tech Stack

• Framework: ElectroBun (Bun-based desktop framework)
• Language: TypeScript + Swift (privileged helper)
• Proxy: Bun-native TLS interception with BoringSSL
• Storage: SQLite with batched writes
• DNS: DNS-over-HTTPS for upstream resolution
• Platforms: macOS (Linux planned)

Privacy

AgentTap is fully local. No telemetry, no cloud, no analytics. Your traces are yours.

License

GPL-3.0