Every gated call yields a ReceiptV1:
  • kind — spend (buyer-initiated) or earn (seller-initiated).
  • decision — outcome of the call:
    • allow — policy gate passed and (for spend receipts) payment settled. tx_sig is set.
    • deny — policy gate denied the call before any payment was attempted. No fetch was made.
    • rejected — policy gate allowed the call but settlement failed (insufficient balance, facilitator/RPC error, 402 with no PAYMENT-RESPONSE, etc). reason carries the failure cause; tx_sig is null.
  • reason — human-readable explanation when decision !== 'allow' (e.g. insufficient_balance, insufficient_allowance, preferred_asset_unavailable: …, transaction_simulation, replay, denyHost, Network error — …).
  • price — when present, amount is the atomic integer string for the SPL mint in asset (use @leash/core format helpers); currency is the human ticker (USDC / USDT / USDG) for the settled or quoted mint.
  • price.network — friendly Leash slug (solana-devnet, solana-mainnet, solana-testnet) — never the raw CAIP-2 chain id (solana:<genesis>).
  • nonce — gapless, per-agent, monotonically increasing from 0.
  • prev_receipt_hash — null at genesis, otherwise the previous receipt’s hash.
  • receipt_hash — sha256(canonicalJson(receipt without receipt_hash)).
Verify any feed with @leash/core verifyReceiptChain or the leash-conformance CLI shipped from @leash/testing.

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Receipts by default

In v0.2 the SDK publishes receipts automatically. You no longer have to write the onReceipt plumbing yourself — createBuyer and createSeller resolve a receipt sink at startup using this fall-back chain:
  1. onReceipt: (r) => … — explicit function. Always wins.
  2. onReceipt: false — explicit opt-out. No forwarding, no errors.
  3. receipts: { runnerUrl, apiUrl, apiKey } — config object.
  4. Environment defaults:
    • LEASH_RUNNER_URL — POST to /a/<mint>/receipts on the local runner.
    • LEASH_API_URL + LEASH_API_KEY — POST to /v1/receipts/<mint>.
    • LEASH_RECEIPTS_DISABLED=1 — global kill switch (overrides everything).
When more than one destination is configured, the kit fans out. A failure in one sink never blocks settlement — the buyer still gets its Response, the seller still gets 200. Failures are logged via console.warn. The agent’s on-chain identity also advertises a default services.receipts URL of https://api.leash.market/v1/receipts/{agent} so any explorer or third-party indexer can find the feed without out-of-band coordination. Override with receiptsUrl on createAgent, the LEASH_RECEIPTS_URL env, or LEASH_NO_RECEIPTS_URL=1 to disable. See Receipts API for the API surface and @leash/buyer-kit / @leash/seller-kit for the kit-level options.