Assay Protocol

Portable, independently verifiable evidence packs for AI decisions.

Assay turns AI activity into signed proof packs another party can verify offline. That matters when you need to answer boring, expensive questions:

• What happened?
• What policy ran?
• Was the evidence changed after the fact?
• Can an assessor or buyer verify it without trusting our server?

This repo is the public verification contract and documentation layer for Assay evidence packs.

It is not an agent framework. It is not a runtime governance platform. It is not a claim that cryptography replaces compliance work.

It is the part that makes evidence portable.

Start Here

• Need the commercial shape first? Read Article 11 / Annex IV working map
• Want to verify a specimen pack right now? Try assay-agent-demo
• Want a browser verifier? Use the proof gallery verifier
• Need the formal spec? Read SPEC.md

Spec status: v1.0.0-rc1 — Release Candidate, pre-release. Dated 2025-12-10. The contract may change before 1.0.0. See SPEC.md for the normative version.

What Assay Evidence Packs Give You

• Tamper evidence: change one byte after signing and verification fails
• Offline verification: no vendor server required
• Signer identity: the pack carries the public key needed to verify the signature
• Execution context: run identifiers, timestamps, receipt counts, and policy hashes travel with the pack
• Human-readable summary: the same pack includes a verifier transcript a reviewer can read without parsing JSON

What This Repo Covers

This repo defines the verification-facing shape of an Assay proof pack:

• signed manifest
• receipt bundle
• verification report
• verification transcript
• schema and canonicalization expectations

For regulated buyers, auditors, and assessors, the key point is simple:

Assay does not ask you to trust our dashboard. It gives you an artifact you can verify yourself.

What It Does Not Claim

Assay proof packs do not by themselves prove:

• that the signer was honest
• that every system action was instrumented
• that the model output was correct, fair, or safe
• that a proof pack alone satisfies all of Article 11 / Annex IV

Those boundaries matter. Assay is strongest as supporting technical evidence inside a wider compliance, audit, or incident workflow.

Evidence Pack Anatomy

Typical pack contents:

proof_pack/
  receipt_pack.jsonl
  verify_report.json
  verify_transcript.md
  pack_manifest.json
  pack_signature.sig

At minimum, these files let a third party answer:

• did the evidence change?
• who signed it?
• when was it created?
• how many receipts are in scope?
• did verification pass?

Where Assay Helps

Assay is useful anywhere another party needs more than logs:

• regulated sales: vendor packets attached to security, compliance, or trust reviews
• audits: technical evidence that can be checked outside the operator's environment
• incidents: a stable, signed packet that survives post-hoc scrutiny
• internal assurance: proving policy execution and retaining honest failures

Documents

Buyer- and Assessor-Facing

File	Purpose
ARTICLE11_ANNEXIV_MAPPING.md	Working map from Assay proof-pack artifacts to EU AI Act Article 11 / Annex IV expectations

Normative And Implementor Docs

File	Purpose
SPEC.md	Full protocol specification
FOR_HUMANS.md	Plain-English explainer for the broader protocol surface
CONSTITUTIONAL_RECEIPT_STANDARD_v0.1.md	Receipt-format notes for signed evidence artifacts
schemas/	Machine-readable schemas
reference/python_gateway	Reference implementation
MCP_MINIMUM_PROFILE.md	MCP gateway control profile
EXECUTOR_MEMBRANE_PROFILE.md	Executor membrane profile
RCE_PROFILE.md	Replay-constrained episode profile
CONTROL_MAP.md	MUST-to-hook mapping
MCP_GATEWAY_MAP.md	Gateway enforcement hooks and code patterns

Quick Technical Start

If you want to exercise the reference implementation:

cd reference/python_gateway
python3 -m venv .venv && source .venv/bin/activate
pip install pytest
PYTHONPATH=src pytest tests/ -v

If you want to verify a real pack:

pipx install assay-ai
assay verify-pack proof_pack/

Related Repos

Repo	Purpose
assay	Core CLI and SDK for generating and verifying proof packs
assay-verify-ts	Independent TypeScript verifier
assay-proof-gallery	Public specimen packs and browser verifier
assay-ledger	Optional transparency anchor, not required for offline verification

License

CC BY 4.0 for specification text. MIT for reference implementation code.