TAP Protocol

The Trust Accountability Protocol (TAP) is the open standard underlying the Truss platform. It defines a vendor-neutral specification for AI agent authorization and verifiable evidence chains, licensed under Apache 2.0.

Core Specifications

  • Mandate format — The structure and serialization of signed agent authorizations, including scope constraints, temporal bounds, and cryptographic signatures.
  • Evidence package structure — The format for bundling and signing action records into verifiable evidence packages, supporting multiple package types and dual-signing.
  • Delegation chain semantics — Rules for extending authority through delegation chains, including scope narrowing, nonce replay protection, and temporal expiry.
  • Cryptographic signing scheme — Ed25519-based signing with SHA-256 hashing, defining exactly what is signed and how signatures are verified.

Key Principles

  • Non-repudiation — All mandates and evidence carry cryptographic signatures that cannot be denied by the signer.
  • Chain of custody — Every action is linked back to its originating mandate through an auditable chain.
  • Scope narrowing — Delegations and sub-mandates must restrict rather than expand scope.
  • Temporal constraints — All authorizations have explicit time bounds, with delegation hops limited to 24 hours.
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