Agent Host Protocol

A synchronized, multi-client state protocol for AI agent sessions.

Read the documentation →

Overview

The Agent Host Protocol (AHP) defines how a portable, standalone sessions server communicates with its clients. Multiple clients can connect to the server and see a synchronized view of AI agent sessions through immutable state, pure reducers, and write-ahead reconciliation.

Client libraries

Language	Package	Version	Source
Rust	ahp · ahp-types · ahp-ws		clients/rust/ · CHANGELOG
TypeScript	@microsoft/agent-host-protocol		clients/typescript/ · CHANGELOG
Kotlin	com.microsoft.agenthostprotocol:agent-host-protocol		clients/kotlin/ · CHANGELOG
Go	github.com/microsoft/agent-host-protocol/clients/go		clients/go/ · CHANGELOG
Swift	SwiftPM: microsoft/agent-host-protocol		package README · CHANGELOG

Other clients: AHPX (CLI + Node.js client) and VS Code (built-in Agent Sessions client).

The Rust, Swift, and Go SDKs ship a MultiHostClient for talking to two or more hosts at once (single-host consumers use the same API via MultiHostClient::single / .single(...) / hosts.Single(...)). See Connecting to Multiple Hosts.

Servers

• VS Code agent host — The reference AHP server implementation (src/vs/platform/agentHost/node/).

Versioning and releases

Each language client and the spec itself release independently on their own SemVer tracks. See docs/specification/versioning.md for the protocol-level rules and RELEASING.md for the release mechanics (tag conventions, CHANGELOG / metadata enforcement, required CI environments).

Development

# Install dependencies
npm install
# Start local dev server
npm run docs:dev
# Build for production
npm run docs:build
# Preview production build
npm run docs:preview

License

MIT