Integration: Agent Action Receipts (AAR) for verifiable sandbox action provenance

[Cyberweasel777]

Problem

OpenSandbox provides secure agent runtime sandboxing — but actions taken inside the sandbox currently have no cryptographic proof trail. When an agent executes code, makes API calls, or modifies state inside a sandbox, there's no standard way to prove what happened, who authorized it, or verify the outcome.

Proposal: Agent Action Receipt (AAR) Integration

AAR is an open standard (MIT) for cryptographically signed receipts that travel with every agent action:

• Ed25519 signature over canonicalized JSON (JCS-SORTED-UTF8-NOWS)
• SHA-256 input/output hashing — proves data without revealing it (privacy-preserving)
• Transport-agnostic — HTTP header, response body, or logged alongside sandbox execution

How it could work with OpenSandbox

1. Sandbox wraps each agent action (API call, file write, code execution) with an AAR receipt
2. Receipt captures: agent identity, principal authorization, action type/target, input/output hashes, cost, timestamp
3. Receipts are signed with the sandbox's Ed25519 key
4. Any consumer of the sandbox output can independently verify the receipt chain

SDK

npm install @botindex/aar

Drop-in Express middleware or manual receipt builder. Single dependency (tweetnacl). TypeScript.

Compatibility

• Mastercard Verifiable Intent (March 5, 2026) — bidirectional mapping included
• x402 (Coinbase) — complementary payment verification

Links

• Spec: https://github.com/Cyberweasel777/agent-action-receipt-spec
• JSON Schema: https://github.com/Cyberweasel777/agent-action-receipt-spec/blob/main/schema/receipt.json

Happy to contribute a PR if there's interest.