Withseismic Tools
- Updated February 14, 2026
- dougwithseismic/node-mitm-proxy
@withseismic/mitm is a local man-in-the-middle HTTP proxy packaged as a Claude Code plugin so developers and agents can capture, inspect, and rewrite traffic in real time.
About
withseismic-tools marketplace distributes the @withseismic/mitm Claude Code plugin built on a local man-in-the-middle proxy. You can see full request and response detail, block analytics, mock missing APIs, and hot-reload TypeScript transform rules without restarting the proxy. Reach for it when you or your agent need programmatic network debugging alongside npx @withseismic/mitm during API integration work.
- Local HTTP/HTTPS capture with terminal UI and REST API
- Hot-reload TypeScript rule engine for rewrites and mocks
- Claude plugin skills to inspect traffic and manage rules via curl
Withseismic Tools by the numbers
- Data as of Jul 7, 2026 (Skillselion catalog sync)
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| Last updated | February 14, 2026 |
|---|---|
| Repository | dougwithseismic/node-mitm-proxy ↗ |
How do you see and safely mutate live HTTP/HTTPS calls from your app without rebuilding clients or guessing what left the wire?
Run a local MITM proxy with Claude skills to capture, mock, block, or rewrite HTTP traffic while debugging apps and APIs.
Who is it for?
Developers debugging API integrations who want a MITM proxy plus agent skills against the local REST control API.
Skip if: Production traffic routing or teams that cannot install local trust certificates for HTTPS interception.
What you get
A local proxy UI and API expose captured traffic, rules, mocks, and breakpoints your Claude session can drive.
Plugins in this marketplace
1 plugin - install individually after you add the marketplace.
Recommended Marketplaces
FAQ
How do I start the proxy quickly?
The README documents npx @withseismic/mitm, which handles certs and prints required environment variables on first run.
Does the plugin require MCP?
No—the README states agent skills use curl against the local REST API on port 8889 instead of an MCP server.