Bond verification

A bond is the part of fleet that bitcoin makes real. An OC Pledge — and, optionally, an OC Agent delegation — references an OrangeCheck attestation that binds a bitcoin address to an unspent UTXO. The trust weight is sats_bonded × days_unspent: sats you cannot cheaply fake, age you cannot backdate, on a UTXO you have not spent. Swap bitcoin for an ordinary keypair and the bond becomes an unverifiable assertion — which is exactly why it is the one thing the settlement and authorization rails around fleet do not offer.

The rule that keeps this honest: a bond is only ever re-resolved against live chain state, never read from stored metadata. fleet does not ask you to trust its database. It hands you a figure it just recomputed from the chain, names the endpoints it read, and invites you to reproduce it yourself.

What the gate checks (SPEC §8)

verifyBond in @orangecheck/pledge-core is the canonical gate. Given a pledge and the verifier's clock now, it resolves the bond's attestation against live UTXO state and applies five checks:

The result depends on chain state at now, not at the moment the pledge was sworn. A bond that was valid when sworn and is spent today fails today. That is the point — a counterparty checking an agent before relying on it gets the current truth, not a historical snapshot.

The endpoint

GET https://fleet.ochk.io/api/bond?attestation_id=<64-hex>

Public, no auth, no project gate — a counterparty must be able to verify a bond without a fleet account. It trusts no stored fleet row: every call hits the chain and the relays.

Add a swearer and thresholds to get the full §8 verdict:

GET /api/bond?attestation_id=<64-hex>&swearer=<bc1…>&min_sats=<n>&min_days=<n>

Response

{
    "ok": true,
    // present only when swearer + min_sats + min_days are supplied:
    "verdict": { "ok": true, "sats_bonded": 1000000, "days_unspent": 212 },
    "resolution": {
        "found": true,
        "signature_valid": true,
        "address": "bc1q…",
        "sats_bonded": 1000000, // live, computed via SPEC §5.4 oldest-first greedy
        "days_unspent": 212, // live, from the youngest UTXO in the bonded set
        "spent": false,
        "reasons": [],
        "checked_at": "2026-06-04T06:36:56.328Z", // freshness stamp
        "sources": {
            // named trust anchors (invariant #8)
            "chain": "https://mempool.space/api",
            "relays": [
                "wss://relay.nostr.band",
                "wss://nos.lol",
                "…",
                "wss://relay.ochk.io",
            ],
        },
    },
}

A failed verdict carries a code:

{ "ok": true, "verdict": { "ok": false, "code": "E_BOND_SPENT", "message": "…" }, "resolution": { … } }

If the chain or relays are unreachable, resolution.found is false with a resolution_failed reason. fleet never fakes a pass: an unverifiable bond is reported as unverifiable, not as valid.

curl -s 'https://fleet.ochk.io/api/bond?attestation_id=<id>&swearer=bc1q…&min_sats=1000000&min_days=180' | jq .verdict

How the figures are computed

sats_bonded and days_unspent come from the OC Attest verification algorithm (SPEC §5.4), shared with @orangecheck/sdk:

1. Discover the attestation on the relay set by its content-addressed id and re-verify its BIP-322 signature.
2. Fetch the confirmed UTXOs for the attested address from Esplora.
3. Select bonded UTXOs oldest-first until they cover the attested bond: amount; sats_bonded is exactly that amount (surplus is ignored), days_unspent is the age of the youngest UTXO in the bonded set.

Honest limitations (v0)

• verifyBond proves unspent-at-check-time only. It cannot prevent the swearer from spending the UTXO a block later. The mitigation is continuous re-resolution plus a published re-attestation cadence — not a custodial lock. A covenant or timelock construction would drift toward custody and break the no-custody invariant, so fleet does not use one.
• Breach is reputational, never financial. Funds never move. A spent bond or a broken pledge attaches a permanent, public, address-keyed record — it does not let fleet, or anyone, seize sats. fleet holds no keys and runs no payout wallet.

Verify it yourself

Everything above is reproducible without fleet. Fetch the attestation from any relay, re-derive its id as sha256(canonical_message), re-check the BIP-322 signature against the address, query the address's UTXOs against your own bitcoin node or Esplora instance, and apply the §5.4 rule. The @orangecheck/sdk check() function does exactly this in one call. fleet runs the managed copy; the chain is the source of truth.