Corroborate MCP server

corroborate-mcp

The honest corroboration layer for AI agents. Hand it a claim; it tells you how independently that claim is actually being reported — and shows its work.

An AP story echoed by 40 outlets is one origin, not 40 citations. Other verifiers count citations; Corroborate counts independent origins — syndication-aware — then publishes its own error rates and discloses coverage gaps. That's the judgment layer raw search and citation-checkers skip.

corroborate_claim("NASA delayed the Artemis III landing")   → CONFIRMED       4 independent origins · conf 0.9
corroborate_claim("Zorblatt Corp acquired Portugal")        → UNCORROBORATED  0 origins · conf 0.05

When an agent should call this

• Before relying on a current-event / news claim — is it independently reported, or one source echoed everywhere?
• To rank or filter sources by genuine independence, with a confidence score.
• When you need a verdict you can defend — every answer ships its evidence, its confidence, and its own caveats.

Not a web search engine (use Exa/Tavily/Brave for that) and not a human fact-checking network. It's the narrow, honest primitive in between: how independently is this reported?

Why it's trustworthy — by design

What it measures — and what it doesn't

Reporting corroboration, not truth. A claim every outlet syndicated from one wire story comes back SINGLE_SOURCE. A claim nobody covers comes back UNCORROBORATED even if true. The verdict states exactly what was measured, flags its weaknesses in notes, and sets coverage:"degraded" when an engine was down — so absence of evidence is never quietly sold as evidence of absence.

Quickstart

Requires Node ≥ 18. No keys, no config.

Claude Code

claude mcp add corroborate -- npx -y corroborate-mcp

Claude Desktop / Cursor / any MCP client (claudedesktopconfig.json, .cursor/mcp.json, …)

{ "mcpServers": { "corroborate": { "command": "npx", "args": ["-y", "corroborate-mcp"] } } }

Try it with no MCP client

npx corroborate-mcp   # starts the stdio server (silent = healthy)
# or from a checkout:  node cli.js "The Federal Reserve held interest rates steady"

Tools

Shortened. The full README is on GitHub.