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mrbrutti/aitmproxy

v0.1.0

aitmproxy — an intercepting proxy for authorized security testing. Capture, inspect, intercept and mutate, replay, and turn traffic into findings and proof-of-concept exploits, driven over MCP.

GitHub

aitmproxy plugin

A plugin that drives aitmproxy — a Rust intercepting proxy for authorized security testing — over MCP. Point it at traffic you are authorized to test, then capture, inspect, intercept and mutate, replay or craft requests, and turn a finding into a reproducible proof-of-concept, all from your AI host.

The same MCP server backs every host; only the presentation differs:

  • ChatGPT and Claude Desktop / claude.ai render the rich MCP Apps widgets (the flow table, flow detail, findings, scope, PoC result and proxy status), coloured from the shared design tokens.
  • Claude Code is text-only — it sees each tool's structuredContent and the bundled aitmproxy-rendering skill turns that into clean markdown tables with method / status / severity badges. No widget is drawn there, and none is needed.

Authorized engagements only. Active tools (flow.replay, request.send, ws.send, poc.run, scan.discover, browser.*) send real traffic and are scope-gated. Operate only against targets covered by a written engagement you are authorized to test.

Package layout

One directory, two manifests — one tree of shared skills and commands:

aitmproxy-plugin/
  .claude-plugin/
    plugin.json          # Claude plugin manifest
    marketplace.json     # Claude marketplace entry (name == plugin name)
  .mcp.json              # Claude: wire `aitm` over stdio
  plugin.json            # OpenAI Agent-Plugins manifest (extensions.com.openai)
  mcp.json               # OpenAI: stdio transport (+ documented HTTP swap)
  skills/                # shared across both hosts
    aitmproxy-overview/        # the whole workflow; OpenAI onboardingSkill
    aitmproxy-rendering/       # text-host rendering (Claude Code)
    aitmproxy-flows-triage/
    aitmproxy-intercept-mutate/
    aitmproxy-findings-poc/
  commands/              # Claude slash commands (agent-side prompts)
    fetch-flows.md  explain-request.md  generate-curl.md  map-remote.md
    triage.md  scope.md  findings.md  intercept.md
  docs/
    install.md           # per-host install + test
    rendering.md         # palette + widget-family guide
    security.md          # streamable-HTTP transport threat model
    tool-reference.md    # generated tool catalog

The Claude manifest lives under .claude-plugin/; the OpenAI manifest is the root plugin.json / mcp.json. Both point at the same skills/ tree. commands/ is Claude-only (OpenAI hosts drive the same actions through skills).

Prerequisite: aitm on PATH

The plugin launches the proxy's own binary as its MCP server. Install aitm so it is on your PATH:

brew tap mrbrutti/aitmproxy && brew install aitm   # Apple Silicon macOS; public tap, no token
# or build from source (repo root), then put target/release/aitm on PATH
# (or `cargo install --path crates/aitm`):
cargo build --release

Linux users install the .deb / .rpm from the release page; see the repo's INSTALL.md. To check it is on PATH, run aitm config get (a one-shot command that prints the redacted config; there is no aitm --version).

Bare aitm serves the stdio MCP server (this is the default transport; there is no aitm mcp subcommand). The same invocation also starts the intercepting proxy listening on 127.0.0.1:8080. Both manifests launch aitm with no subcommand.

Quick install and test

  • Claude Code — /plugin marketplace add ./aitmproxy-plugin then /plugin install aitmproxy. Output renders as text via the aitmproxy-rendering skill.
  • Claude Desktop / claude.ai — add the stdio MCP server (command aitm); the widgets render.
  • ChatGPT (developer mode) — for local testing wrap the stdio aitm command in OpenAI's Secure MCP Tunnel; for a real/submittable endpoint run the streamable-HTTP transport (opt-in in config.yaml; the endpoint is then http://127.0.0.1:8084/mcp).

Full step-by-step for all three hosts, including the HTTP config snippet, is in docs/install.md. Validate the Claude package with claude plugin validate ./aitmproxy-plugin.

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