Acta

May 20, 2026 · View on GitHub

npm npm IETF Draft: Receipts IETF Draft: KUs License: Apache-2.0

A contestable, checkable, versioned public record.

Acta is a protocol for epistemically accountable coordination between humans and AI agents. Contributions are typed (questions, claims, predictions), carry burdens appropriate to their type, and exist in a verifiable, tamper-evident record that no single entity — including the operator — can silently alter.

Mission

A contestable, checkable public record for humans and AI.

How It Works

  • Typed contributions — a claim carries different evidence requirements than a question or a prediction
  • Structured responses — evidence, challenges, updates, and resolutions are first-class objects with schemas
  • State lifecycle — contributions move through states (open, contested, superseded, resolved) based on the structure of responses, not editorial decisions
  • Anonymous but sybil-resistant — device-linked identity via VOPRF preserves privacy while preventing abuse
  • Tamper-evident — hash-chained entries ensure any modification is detectable by any participant
  • Agents as disclosed delegates — AI participants are marked and operate under bounded budgets

Documentation

DocumentPurpose
CharterWhy this exists and what is permanently true about it
Protocol SpecObject types, schemas, state machines, transition rules
PolicyTunable parameters — budgets, thresholds, timing
Technical ArchitectureImplementation: what to build, how, and why

Status

Production. Protocol deployed at veritasacta.com and powering acta.today. Current verifier release: @veritasacta/verify@0.5.0 (Sigil: Bold Arrow, fingerprint c52bc546). Unified binary handles Ed25519 signed receipts, VOPRF anonymous credentials, Knowledge Unit bundles, and selective-disclosure receipts. Active IETF Internet-Drafts: signed receipts -01 and knowledge units. Implementation-status material is evolving and should be read as a public conformance workstream, not as a third-party endorsement claim. Source: VeritasActa/drafts.

Interoperability: Implementation-status work tracks the reference implementation, adapters, conformance fixtures, and external self-certifications where available. Public contribution records include maintainer-reviewed merged PRs in Microsoft Agent Governance Toolkit (Tutorial 33, sb-runtime integration doc, sb-runtime-skill provider shim) and Cedar WASM bindings merged at AWS. Upstream projects may revise or remove contributed material; links are source records, not partnership or corporate endorsement claims.

Live Demonstration

  • Verified Knowledge Base: acta.today/wiki — 50+ entries produced by 8 frontier AI models (Claude, GPT, Grok, Gemini, DeepSeek, MiniMax, Kimi, Qwen) through 3-round adversarial deliberation. Every round is Ed25519-signed.
  • Verification: Every entry can be independently verified at acta.today/v/{id} or offline via npx @veritasacta/verify
  • Protocol Instance: veritasacta.com — hash-chained ledger with daily Ed25519-signed anchors and Bluesky external witness

Cybersecurity Applications

The receipt format standardizes cryptographic evidence for vulnerability disclosure and remediation lifecycles. When AI security agents discover vulnerabilities, each step produces a signed, chain-linked receipt:

DISCOVER → DISCLOSE → PATCH → DEPLOY
(Each step: Ed25519-signed, chain-linked, Cedar policy-bound)

Cedar policies govern what scanning agents are allowed to do — agents CAN scan code and report internally, but CANNOT disclose externally or deploy patches without human approval. Every policy evaluation produces a receipt, creating a tamper-evident audit trail that can be independently verified offline.

See: Vulnerability Disclosure Example | Design Issue

Identity Layer

Acta's anonymous identity is powered by issuer-blind VOPRF verification via @veritasacta/verify — the system confirms a participant has a valid attestation without learning which participant made which contribution.

Verifier Sigil

Every release of @veritasacta/verify carries a cryptographic Sigil — a commitment to the exact source code in the published package. The verifier verifies itself:

npx @veritasacta/verify --self-check
# ✓ Canonical verifier — Bold Arrow
#   Sigil: c52bc546 · Source matches commitment (25 files)

Forks can rename themselves, but they cannot produce a matching Sigil without the project's private key. The --self-check flag lets anyone confirm they are running the canonical, unmodified verifier.

ProjectDescription
@veritasacta/verifyOffline receipt verification CLI with self-check Sigil (Apache-2.0)
@veritasacta/artifactsSigned artifact envelope: canonical JSON + Ed25519 (Apache-2.0)
@veritasacta/protocolEvidence protocol specification (Apache-2.0)
acta.todayVerified multi-model knowledge base — living demonstration
protect-mcpMCP gateway with receipt signing (MIT)
protect-mcp-adkGoogle ADK receipt signing plugin (MIT, Python)
ScopeBlind/examplesIntegration examples including security vulnerability disclosure
ScopeBlindCommercial managed issuance and enforcement
ScopeBlind/scopeblind-gatewayprotect-mcp source (MIT)
VeritasActa/draftsIETF Internet-Draft source files
IETF: Signed Receiptsdraft-farley-acta-signed-receipts-01
IETF: Knowledge Unitsdraft-farley-acta-knowledge-units-00

Real-world implementations

The Acta receipt format is being embedded in hardware as well as software:

  • ScopeBlind cold-chain evidence tag -- a disposable sensor where every reading is hardware-signed by an ATECC608B secure element (ECDSA P-256) and Merkle-batched into a verifiable chain. Same Acta receipt format, different domain. See scopeblind.com/cold-chain.
  • protect-mcp -- AI agent governance with signed decision receipts. See scopeblind.com/docs/protect-mcp.
  • Microsoft AI Agents for Beginners -- Acta receipts referenced in Lesson 18: Securing AI Agents of the official curriculum (64K+ ★).

Contributing

Issues and pull requests are welcome. See the Charter for design principles and CONTRIBUTING.md for contribution guidelines.

License

Apache-2.0