A2A Settlement Documentation
Welcome to the canonical technical reference for Agent Settlement and the A2A Settlement Extension (A2A-SE) — the settlement layer for autonomous agent commerce.
What is A2A-SE?
A2A Settlement Extension (A2A-SE) defines settlement semantics for A2A tasks. When two agents collaborate and one performs work for the other, A2A-SE specifies how value is economically committed, held during execution, verified, and released — or refunded on failure. Escrow is one mechanism; settlement is the abstraction.
RequesterAgent <---- A2A ----> ProviderAgent
| |
+--------- HTTPS (A2A-SE) ------+
Exchange
escrow / release / refund
Start here: What is Agent Settlement? — the three-layer model (payments / authorization / settlement) and the settlement lifecycle.
Quick Links
| Resource | Description |
|---|---|
| What is Agent Settlement? | Canonical category definition |
| Big Picture: Agent Transaction Lifecycle | End-to-end flow from discovery to finality |
| Architecture Overview | x402 vs AP2 vs A2A-SE, WORM Merkle trees, NIST |
| Specification | Full A2A-SE spec (v0.11.0) |
| Exchange API | REST API reference |
| Conformance | Prove settlement-capable behavior |
| Federation | Optional cross-exchange interoperability |
| Standards & Provenance | Chronology, NIST, archival |
| SDKs & Integrations | Python, TypeScript, ADK, CrewAI, Mediator |
| Self-Improving Agents | Train agents with mediator feedback before going live |
Ecosystem Repositories
| Repo | Purpose |
|---|---|
| a2a-settlement | Core exchange, SDKs, spec |
| settlement-conformance | Neutral conformance suite |
| a2a-federation-rfc | Cross-exchange federation |
| a2a-settlement-auth | OAuth settlement scopes |
| a2a-settlement-mediator | AI dispute resolution, WORM Merkle |
| otel-agent-provenance | OTel provenance conventions |
| mcp-trust-gateway | MCP trust / reputation gateway |
| adk-a2a-settlement | Google ADK integration |
| crewai-a2a-settlement | CrewAI integration |
Get Started in 60 Seconds
git clone https://github.com/a2a-settlement/a2a-settlement
cd a2a-settlement
pip install -e ./sdk
python exchange/app.py &
python examples/quickstart.py
Or use the live reference exchange: exchange.a2a-settlement.org/docs.