A small integration surface over a deep security substrate.
Developers should address a customer Embassy, select a target capability, send a governed operation, and receive a correlated result. Identity, transport, policy, evidence, and customer-local execution belong to Legation.
Integrate once. Reach approved customer-side capabilities consistently.
Bind the vendor application or service to a non-human identity and authorized customer scope.
Read the authorized Embassy registry for available agents, MCP servers, tools, or native services.
Send a direct operation or objective with deadline, correlation, and audit context.
Observe long-running work, stream progress, enforce timeouts, or cancel the task.
Consume the approved response and retain the evidence reference for audit correlation.
Make customer-side resources explicit and unambiguous.
legation://acme-production/mcp/records-service/tools/evidence.search legation://acme-production/a2a/review-agent/skills/control-review legation://acme-production/service/billing-engine/operations/calculate
Recommended product contract, not a claim that this exact URI syntax is already shipping.
The Embassy should advertise only what the caller is allowed to see.
{
"embassy": "acme-production",
"capabilities": {
"mcp": { "records-service": ["evidence.search", "system.health"] },
"a2a": { "review-agent": ["control-review"] }
}
}Support real applications—not just one-shot demos.
| Pattern | Required behavior |
|---|---|
| Synchronous | Known, bounded operation with immediate result |
| Asynchronous | Task handle, status, result retrieval, and evidence reference |
| Streaming | Progress, partial output, and controlled cancellation |
| Store-and-forward | Queue work across temporary Embassy disconnection |
| Fan-out | Address multiple customer Embassies without mixing tenant state |
The SDK must expose failure as a first-class state.
- Embassy unreachable versus workload unavailable
- Identity rejected versus policy denied
- Deadline exceeded versus task cancelled
- Projection blocked versus execution failed
- Regional failover versus customer-local degradation
- Evidence committed versus audit delivery delayed
Built as a hardened Rust security platform.
Legation is implemented in memory-safe Rust with unsafe code prohibited across the platform, a provider-isolated cryptography layer, and a modular separation between delivery, governance, transport, identity, custody, evidence, and runtime services.