AHP Rust client/server lifecycle, feature flags, authentication, and validation limits.

AHP Transports

AHP is transport-agnostic at the protocol layer. The Rust crate provides client and server support behind Cargo feature flags.

Feature Flags

Feature	Status	Notes
`stdio`	Implemented, default	Local subprocess harnesses.
`http`	Implemented	HTTP client/server examples; supports API key and bearer auth.
`websocket`	Implemented	WebSocket client/server examples; supports API key and bearer auth via URL query parameters.
`unix-socket`	Implemented	Local IPC on Unix platforms.
`grpc`	Reserved	Feature placeholder; the client returns unsupported for gRPC.
`all-transports`	Convenience	Enables `stdio`, `http`, `websocket`, and `unix-socket`; it does not include `grpc`.

Client Lifecycle

Create AhpClient with a Transport.
Run handshake with agent capabilities.
Send blocking generic events with send_event_decision.
Send specialized events with send_typed_event.
Use full-event APIs when the runtime must preserve session, agent, depth, context, or metadata.
Send ahp/batch only for generic-decision events.
Close the client transport when done.

The Rust client validates JSON-RPC version, response id, error responses, missing results, completed handshake, batchability, and batch decision count.

Server Lifecycle

AhpServer is built around an EventHandler implementation. The handler owns policy, enrichment, approval, audit, and backpressure logic. The server owns protocol validation and dispatch.

The default server advertises:

Config	Default
`timeout_ms`	`10000`
`batch_size`	`100`
`max_depth`	`10`

Builder methods can override harness info, advertised capabilities, and limits.

Authentication

HTTP and WebSocket transports can carry optional auth config:

API key auth.
Bearer auth.

Use deployment secrets or environment variables for real credentials. Examples should use placeholders and avoid committed tokens.

Validation Boundaries

The server validates:

Protocol major-version compatibility during handshake.
Blocking vs notification event direction.
Event depth against max_depth.
Batch size against batch_size.
Batch entries are batchable and return generic Decision.
run_lifecycle, task_list, and verification payload shapes.

The protocol still depends on the runtime to enforce returned decisions. AHP does not sandbox the action itself.