x402 Buyer Guide

How to pay for Council of AI evidence artefacts using x402 (USDC on Base). For agent developers and platform integrators.

The 30-second version

# 1. GET a paid resource → 402 with payment challenge
curl -i https://councilof.ai/api/request-attestation?subject=USDC
# → HTTP/1.1 402 Payment Required
# → X-Payment-Address: 0x212686404A7D1E1fD88F35eD6200c3aF7A78ae31
# → X-Payment-Network: eip155:8453
# → X-Payment-Amount: 
# → X-Payment-Asset: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913

# 2. Pay the challenge (USDC on Base)
# 3. Retry with X-Payment-Signature header
curl -H "X-Payment-Signature: <signed-payment>" \
     https://councilof.ai/api/request-attestation?subject=USDC
# → HTTP/1.1 200 OK + signed receipt + paid artefact

The catalog

10 resources: 1 free + 9 paid. Full discovery at https://councilof.ai/.well-known/x402.json.

ResourceEndpointAmount
Free door/api/free-doorfree (no 402)
Issuance/api/request-attestation?subject=<id>metered — read the 402
Evidence bundle/api/evidence-bundle?obligation=<...>metered — read the 402
Proof bundle/api/proof?bundle=1metered — read the 402
RWA evidence/api/rwa/evidence?asset=<symbol>metered — read the 402
Wrapper parity/api/wrapper/paritymetered — read the 402
Art. 50 marking/api/art50/marking-evidence?url=<...>metered — read the 402
Provider diff/api/feeds/provider-diff?history=1metered — read the 402
Receipts batch/api/receipts/batch?from=<date>metered — read the 402
Data feed/api/eunomia-data?feed=1metered — read the 402

Verification — always free

# Get a card
curl https://councilof.ai/api/card?sha=<64-hex>
# Verify the Ed25519 signature offline
python3 scripts/verify_receipt.py <receipt.jws>
# Or online
curl https://councilof.ai/api/receipts/verify -d '<receipt.jws>'

Common patterns

"I want to know if USDC was measured"

curl https://councilof.ai/api/free-door
curl "https://councilof.ai/api/card?subject=USDC"

"I want a signed receipt for my compliance dossier"

# Paid: settle the 402 challenge (USDC on Base)
curl https://councilof.ai/api/request-attestation?subject=USDC
# Pay the 402 challenge, retry with X-Payment-Signature

"I need an EU AI Act Article 50 evidence bundle"

# Paid: settle the 402 for a full OSCAL 1.1.0 bundle
curl https://councilof.ai/api/evidence-bundle?obligation=article-50&subject=model-id&bundle=1

"I want to prove this card is in your canonical Merkle root"

# One leaf: free
curl "https://councilof.ai/api/proof?sha=<64-hex>"
# Multiple leaves: paid batch (settle the 402)
curl "https://councilof.ai/api/proof?bundle=1"

MCP integration

{"servers":{"csoai-gspc-mcp":{"url":"https://councilof.ai/mcp","stdio":"npx -y [email protected]"}}}

12 tools, 8 free + 4 metered. Same x402 rail.

What we never sell:

Volume pricing

If you settle at volume, contact us for a supported feed — amounts stay in the 402.

[email protected] View pricing