Openevidence MCP

OpenEvidence MCP

Query OpenEvidence from Claude Code, Codex CLI, Antigravity CLI, Claude Desktop, Cursor, Cline, Continue, and any MCP client — authenticated through your own logged-in browser tab. No API key.

What it does

OpenEvidence protects its API with bot detection that blocks plain server requests. This project removes that problem: when your AI tool asks OpenEvidence a question, the request is run inside your own logged-in OpenEvidence browser tab — so it carries your genuine browser session and is never challenged.

A small Chromium browser extension lends its session to a localhost relay; the MCP server speaks to that relay. The extension is a narrowly allowlisted authenticated fetch bridge — all the OpenEvidence logic stays in the local server, and your browser login is the only OpenEvidence credential. No API key, no cookie file, no Playwright, no headless browser.

It is designed for local personal workflows where you already have lawful access to OpenEvidence. It does not bypass authentication, remove access controls, redistribute OpenEvidence content, or include any OpenEvidence data in this repository.

How it works

  Claude / Codex / any MCP client
            │  asks a question (oe_ask)
            ▼
     openevidence-mcp  ──▶  relay daemon  ──▶  browser extension  ──▶  your logged-in
       (stdio server)      127.0.0.1:8787       (runs the fetch)        OpenEvidence tab
            ▲              shared · auto-spawned                              │
            └──────────────────────── answer ◀───────────────────────────────┘

Nothing navigates or pops up — the tab stays where it is. The extension only ever talks to openevidence.com and your local relay (127.0.0.1). The relay runs as a shared daemon that owns port 8787 and outlives every session, so any number of Claude/Codex sessions funnel through the one logged-in tab.

Quick start

git clone https://github.com/htlin222/openevidence-mcp.git
cd openevidence-mcp
make all      # installs deps · builds the MCP server + relay extension ·
              # registers the server into Claude and Codex (whichever CLI you have)

Then the one manual step make all prints (a browser action that can't be scripted):

1. Load the extension — open chrome://extensions (Chrome / Edge / Brave / Arc / Vivaldi / Opera) → turn on Developer mode → Load unpacked → select extension/dist.
2. Stay logged in to openevidence.com in that browser, and keep a tab open. That login is your authentication.
3. Run your AI tool. The server auto-starts the relay and connects to the extension.

Verify and go:

curl -s http://127.0.0.1:8787/health     # expect {"ok":true,"connected":true,"version":1,...}

Then just ask, in any MCP client: “Use OpenEvidence to answer …”. Re-run make all anytime to rebuild + re-register; make help lists every target; make kill-all stops all servers + the relay daemon.

Already installed? Update in one line:

make update    # git pull latest release · rebuild server + extension · re-register