Trust — verify it yourself

Prose is cheap. Every load-bearing claim Metrecept makes ships with the surface that checks it, so nothing here has to be taken on faith.

Every cache HIT carries an X-Ohm-Receipt response header: a compact JWS (EdDSA/Ed25519) signed at the moment of service, stating the replay identity (request_sha256), the upstream tokens that were not re-bought (tokens_replayed), and what the hit was billed (pipe_usd).

# Same body twice — the second response is the HIT and carries the receipt
curl -si https://api.withohm.dev/v1/chat/completions \
  -H "Authorization: Bearer $OHM_API_KEY" -H "Content-Type: application/json" \
  -d '{"model":"mock","messages":[{"role":"user","content":"receipt demo"}]}' \
  | grep -i x-ohm-receipt

Verify it with nothing but the public key directory — no Metrecept code:

python scripts/verify_receipt.py "<X-Ohm-Receipt value>" --base https://api.withohm.dev

The verifier resolves the signing key by its RFC 7638 thumbprint from /.well-known/http-message-signatures-directory and checks the Ed25519 signature. Forged or altered receipts fail. Edge-served hits carry the same receipt — minted by the control plane, so the edge never holds key material.

curl -s https://api.withohm.dev/v1/public/honesty

Machine-readable list of what the pipe will not do — no mid-stream handoff after the first byte, no semantic cache, no auto-paying HTTP 402 pay-per-crawl, no robots evasion, no cache-as-training-corpus — each entry paired with the endpoint that proves or enforces it. If an entry there stops being true, that is an incident, not a copy edit.

OhmBot signs its web fetches with RFC 9421 HTTP Message Signatures (tag="web-bot-auth"); origins verify against the same public directory. Fetch refusals (402 licensed-crawl, robots, 401/403 revocations) are honored and surfaced, never worked around.

• A golden-path check walks the reviewer path against production every night — health, mock miss/hit, provider miss/hit, edge headers, usage counters — pass/fail, not marketing copy.
• Cross-tenant savings counter at /v1/public/stats is always labeled estimate_only: true.