# Sourced RUN — hosted corroboration API

> Free, no-auth, CORS-open endpoint for Sourced corroboration verdicts: POST claims, get back how many independent origins corroborate each one, with receipts. Never "true" — only "corroborated".

## Endpoint

POST https://sourced.run/api/assess (content-type: application/json)

Request: { "claims": [{ "id": string, "title": string, "origin": string, "publishedAt": ISO-8601 }], "clusters"?: { [claimId]: origin[] }, "config"?: { numeric threshold overrides } }

Response: { "verdicts": [ { "corroboration": n, "corroboratingSources": string[], "firstSeenAt": ISO-8601, "signal": "confirmed"|"breaking"|"developing"|null } | null ] } — verdicts[i] belongs to claims[i]; null = unassessable claim (passes through unlabeled, never an error).

Semantics: stateless and batch-scoped — corroboration is computed across the claims in one request; same titles from different origins corroborate; copies from the same origin collapse to 1 (independence by origin); single-origin claims get signal null and no receipts. Limits: 200 claims / 200 kB per call. GET the endpoint for a machine-readable usage summary. Errors: 400 { "error": string } for a malformed envelope only.

Example:
curl -s https://sourced.run/api/assess -H "content-type: application/json" -d '{"claims":[{"id":"a","title":"Major dam breach reported upstream","origin":"reuters","publishedAt":"2026-07-10T21:00:00Z"},{"id":"b","title":"Major dam breach reported upstream","origin":"bbc","publishedAt":"2026-07-10T21:04:00Z"}]}'
→ verdicts[1] = { "corroboration": 2, "corroboratingSources": ["reuters"], "signal": "breaking", ... }

Machine-readable contract: https://sourced.run/openapi.json (OpenAPI 3.1 — /api/assess and /api/verify).
Also on this host: POST /api/verify — verify a Sourced transparency chain programmatically ({ chain: LogRecord[] } or { jsonl }, optional inclusion proof via { payload, seq }).

## For AI agents

MCP server (stdio): `npx -y @sourcedhq/mcp` — server name "sourced", tools: assess (session memory accumulates corroboration across calls), verify_chain, run_conformance. Persistent event memory (first-seen across runs) = run @sourcedhq/core yourself with a store.

## More

- [Full specification](https://sourced.ink) · [spec llms.txt](https://sourced.ink/llms.txt)
- [Proof: live adversarial suite + chain verifier](https://sourced.network)