[fernando-mendoza]

Adds examples/x402-policy-daily-budget/: a per-agent daily spend cap for the pre-sign policy hook (initX402({ policy })). This PR only adds files under examples/ and does not touch the hook.

How each "Done when" item is met

• Atomic spend check: src/budget-store.ts tryCommit checks spent + amount <= cap and writes the new total in one synchronous step, with no await between the read and the write. The README and the source show the multi-process version as one conditional SQL UPDATE … WHERE spent + $amt <= $cap (0 rows means DENY).
• ALLOW contents and fail-closed version: ALLOW echoes the exact ctx.contextHash, includes policyVersion, and sets expiresAt = now + ttlMs (2 s by default). hook() wires currentVersion and sets requireExpiry: true. update() bumps the version, so the SDK refuses an earlier ALLOW with STALE.
• Tests (test/daily-budget-policy.test.ts): ALLOW; DENY over the cap (nothing committed); a concurrent pair where exactly one passes; 50 concurrent requests that never overspend; a stale policy version; caps per agent and per UTC day; non-integer and non-positive amounts.
• README: it says plainly that this is a reference, not a guarantee, and lists what it does not solve.

What it does not solve

• L01, pending-capacity reservation: budget is committed on ALLOW, not when the payment settles. Nothing releases or reconciles it against on-chain settlement.
• L02, same-process signer access: code that holds the raw signer can sign without asking the policy, and nothing on-chain enforces the cap.
• The version check is not atomic with signing, and the in-memory store resets on restart.

Test results (Node 22.23.3, npm 10; SDK built as in CI)

• npm ci: OK
• npm test: 7 tests, 7 pass, 0 fail
• npm run typecheck: no errors
• npm start: 600000 => ALLOW, 600000 => DENY (daily cap exceeded), 400000 => ALLOW

Closes #127

[fernando-mendoza]

@Eras256 un recordatorio amable 🙌 Tengo dos PRs listos para review, con CI en verde donde aplica:

• feat(examples): daily-budget policy engine for the pre-sign hook (#127) #146: ejemplo de motor de presupuesto diario (cierra Example: a daily-budget policy engine for the pre-sign policy hook #127)
• test(sdk): make the x402Serve smoke test hermetic (#126) #151: smoke test hermético de x402Serve (cierra x402serve smoke test: make it hermetic (no real facilitator calls) #126)

Además ya tengo listos en local el #144 (CI para packages/mcp) y el #145 (Dependabot). No los abro todavía para no saturarte, salvo que prefieras que los suba ya. ¡Gracias!

[Eras256]

Reviewed, this is ready. The atomic tryCommit, the concurrency tests and the "what this does not solve" section are exactly what #127 asked for, and CI is green including the new typecheck job.

One small thing before I merge: the last line of the README links to AgentLedger. Since it's your product, could you add a short disclosure so readers know? Something like:

see [AgentLedger](https://useagentledger.xyz) (disclosure: built by the author of this example).

Push that and I'll merge right away. Thanks!

Drafted with AI assistance (Claude Opus 5.5) and reviewed by Giovanny.

[Eras256]

Disclosure added, thanks. Merging.

🤖 Generated with Claude Code