mitmproxy-mcp

name	mitmproxy-mcp
description	Analyze, intercept, and replay HTTP/HTTPS traffic through mitmproxy. Gives you 20 MCP tools for traffic analysis, request replay, interception control, and proxy configuration. Use when debugging APIs, testing security, or understanding how an application talks to its backend.

mitmproxy-mcp

HTTP/HTTPS traffic analysis, interception, and replay through mitmproxy.

Prerequisites

• mitmproxy running with the mitmproxy-mcp addon loaded
• MCP server available at http://localhost:9011/sse (SSE transport)

If the MCP server is not connected, tell the user to start mitmproxy first:

mitmproxy      # or mitmweb, or mitmdump

The addon and MCP server start automatically if configured in ~/.mitmproxy/config.yaml. For dependency-safe startup, install shims once with mitmproxy-mcp install-shims --force.

When to Use This Skill

• User asks to inspect, debug, or analyze HTTP traffic
• User wants to replay or modify an HTTP request
• User wants to intercept requests matching a pattern
• User needs to export captured traffic (HAR format)
• User is doing API debugging or security testing

Available Tools (20)

Flow Tools -- querying captured traffic

• get_flows -- list captured flows with optional filtering by method, URL pattern, or status code. Supports limit and offset for pagination.
• get_flow_by_id -- get full request and response details for a single flow
• search_flows -- search flows by regex pattern across URL, method, status, and headers
• get_flow_request -- get only the request portion of a flow
• get_flow_response -- get only the response portion of a flow
• get_flow_count -- count of currently stored flows
• clear_flows -- clear all stored flows and clear mitmproxy's flow view when sync includes clear
• export_flows -- export flows to HAR 1.2 format. Optionally pass specific flow IDs.

Replay Tools -- sending and modifying requests

• replay_request -- replay a captured request exactly as-is. Replays in-place when view sync includes replay; otherwise creates a detached replay flow.
• send_request -- send a new HTTP request. Parameters: url (required), method (default GET), headers, body.
• modify_and_send -- take an existing flow, change its method/url/headers/body, and send it. Useful for testing variations.
• duplicate_flow -- clone a flow without sending it. Useful for before/after comparisons.

Replay tool flows are reflected to mitmproxy's flow list when mcp_view_sync_actions includes replay (default: all).

Intercept Tools -- pausing and controlling live traffic

• set_intercept_filter -- set a mitmproxy filter expression to intercept matching requests. Uses mitmproxy filter syntax: ~u example.com, ~m POST, ~u api & ~m GET. Pass empty string to disable.
• get_intercepted_flows -- list flows currently paused by interception
• resume_flow -- resume a single intercepted flow
• resume_all -- resume all intercepted flows
• drop_flow -- drop/kill an intercepted flow without forwarding it

Config Tools -- proxy settings

• get_options -- get current mitmproxy option values. Pass specific keys or get curated defaults.
• set_option -- set a mitmproxy option at runtime. Some dangerous options (listen_host, listen_port, mode, server, ssl_insecure) are blocked.
• get_status -- get proxy status: version, listen address, mode, flow count, intercept settings.

Workflow Patterns

Basic traffic inspection

1. Make sure mitmproxy is running and proxying the target traffic
2. Use get_flows to see what has been captured
3. Use get_flow_by_id to drill into specific requests/responses
4. Use search_flows with a regex to find specific patterns

Replaying and modifying requests

1. Find the flow you want with get_flows or search_flows
2. Use replay_request to resend it exactly
3. Or use modify_and_send to change headers, body, or URL before sending
4. Compare the original and modified responses

Intercepting live traffic

1. Set a filter with set_intercept_filter (e.g. ~u api.example.com & ~m POST)
2. Wait for matching requests -- they will be paused
3. Use get_intercepted_flows to see what is waiting
4. Use resume_flow or drop_flow to control each one
5. Use set_intercept_filter with empty string to stop intercepting

Important Notes

• Sensitive data redaction is off by default. Enable with mcp_redact: true in mitmproxy config to redact tokens, passwords, API keys, and JWTs
• Use mcp_view_sync_actions to control what syncs to mitmproxy's view (all, none, replay, clear, or replay,clear)
• Request/response bodies are truncated to 10KB to prevent context overflow
• All data is in-memory only -- cleared when mitmproxy stops
• The proxy stores up to 1000 flows by default (oldest evicted first)