Tool	What
`rerank`	Rerank documents by relevance to a query. Cohere-compatible response shape (`results: [{index, relevance_score}]`), so it drops into an existing `co.rerank()` call. ~$0.001/call over x402 (roughly half Cohere Rerank's list price) or a free tier.

Why

A lexical+spectral hybrid reranker, not a cross-encoder: strong when the candidates already share vocabulary with the query, which is the common case for RAG retrieval output and document/tool shortlists. Built for high-volume, latency- and cost-sensitive reranking — narrowing a retrieval candidate set, deduping, triage — rather than close semantic disambiguation between near-identical phrasings. Pay-per-call and about half the price is the trade for that.

Verified against the real cohere.Client, cohere.ClientV2 and voyageai.Client SDKs: point base_url at this API and existing rerank code runs unmodified.

Install

pip install ryrank-mcp
claude mcp add ryrank --env RYRANK_API=https://trigeochiral.com -- ryrank-mcp

or with uvx (no install):

claude mcp add ryrank --env RYRANK_API=https://trigeochiral.com -- uvx ryrank-mcp

Optional: RYRANK_XPAYMENT = a base64 x402 X-PAYMENT payload, to make paid calls past the free tier. Without it you get 25 free calls/day per IP.

Direct HTTP (no MCP)

curl -sX POST https://trigeochiral.com/v1/rerank -H 'content-type: application/json' \
  -d '{"query":"how do I reset my password","documents":["Go to Settings > Security and click Reset Password.","Our refund policy allows returns within 30 days."],"top_n":2}'

Also speaks the exact Cohere v2 (POST /v2/rerank) and Voyage (POST /voyage/v1/rerank) request and response shapes, so their official SDKs work unmodified with just a base_url override — see https://trigeochiral.com for details.