occam_claim_check¶
Status: verified against src/FFOccamMcp.Core/Tools/OccamClaimCheckTool.cs @ 2026-09-29
Profiles: researcher, auditor, full — not default reader, minimal, or basic
Contract depth: MCP API · runtime tools/list
Purpose¶
Live claim grounding for one sentence against one URL: fetch via transcode pipeline, rank blocks by BM25 vs claim, return top matches with Merkle leaf + proof. Shows which source text was retrieved; does not decide support vs refute (verdict always not_evaluated).
When to use / when not¶
| Use when | Do not use when |
|---|---|
| Provable block(s) from this URL for one assertion | Host-side stance status → occam_attest |
You will judge support yourself from matches[].text |
Full page markdown only → occam_transcode |
Re-check leaf + proof via occam_verify citation |
Expecting truth from the claim string alone |
Parameters¶
| Name | Required | Default | Meaning |
|---|---|---|---|
claim |
yes | — | Assertion to ground (a sentence) |
url |
yes | — | HTTP(S) URL |
backend_policy |
no | http_then_browser |
http, browser, or http_then_browser |
session_profile |
no | null | Optional session profile id |
max_matches |
no | 3 |
Max blocks (1–10; silently clamped) |
Fixed internally: json_blocks=true, playbook_policy=auto; no caller max_tokens / fit_markdown.
Response shape¶
Success: found, retrieved (= found), verdict: not_evaluated, optional proven when found:false (retrieval-complete negative only — not semantic absence), blockMerkleRoot, matches[] (blockIndex, text, score, leaf, proof[], …), optional receipt, timestamp.
Failure: failure: { code, message } — page content unknown. Distinct from success with found: false.
Common failure codes¶
invalid_arguments; plus transcode taxonomy on fetch/extract. Full list: failure-codes.
Related env vars¶
OCCAM_PROFILE, OCCAM_RECEIPTS, session profiles — configuration.