microsoft/agent-host-protocol

microsoft/agent-host-protocol

Description: Synchronized multi-client state for AI agent sessions

Language: Swift

License: MIT

Stars: 41

Forks: 10

Open issues: 19

Created: 2026-03-12T23:52:11Z

Pushed: 2026-06-10T20:46:58Z

Default branch: main

Fork: no

Archived: no

README:

Agent Host Protocol

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

[Read the documentation →](https://microsoft.github.io/agent-host-protocol/)

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.

Implementations

Clients

• Swift — Add https://github.com/microsoft/agent-host-protocol as a Swift Package Manager dependency (resolves bare vX.Y.Z tags at the repo root) to use the AgentHostProtocol types/reducers library or the AgentHostProtocolClient single-host and multi-host client library. See the [Swift package README](clients/swift/AgentHostProtocol/README.md), [clients/swift/CHANGELOG.md](clients/swift/CHANGELOG.md), and [clients/swift/](clients/swift/) for the example iOS client. The Package.swift manifest lives at the repository root because SwiftPM only resolves manifests at the root of a remote git repo; the actual Swift sources live under clients/swift/AgentHostProtocol/.
• Rust — See [clients/rust/](clients/rust/) for the ahp, ahp-types, and ahp-ws crates. Released to crates.io via rust/vX.Y.Z tags ([CHANGELOG](clients/rust/CHANGELOG.md)).
• Kotlin — Add com.microsoft.agenthostprotocol:agent-host-protocol from Maven Central to use from Android or any JVM project. See [clients/kotlin/](clients/kotlin/) for the source and [CHANGELOG](clients/kotlin/CHANGELOG.md). Released via kotlin/vX.Y.Z tags.
• TypeScript — Install @microsoft/agent-host-protocol to use the wire types, reducers, AhpClient, and the WebSocketTransport. See [clients/typescript/](clients/typescript/) and [CHANGELOG](clients/typescript/CHANGELOG.md). Released via typescript/vX.Y.Z tags; the Azure DevOps publish pipeline at [clients/typescript/pipeline.yml](clients/typescript/pipeline.yml) picks up the tag, validates it, and publishes to npm.
• Go — go get github.com/microsoft/agent-host-protocol/clients/go to use the ahptypes wire types, the ahp async client (client + pure reducers + pluggable Transport), and the ahpws WebSocket transport. See [clients/go/](clients/go/) and [CHANGELOG](clients/go/CHANGELOG.md). Released via clients/go/vX.Y.Z tags — the Go module proxy indexes the directory-prefixed tag directly from this repo, so there is no separate package registry.
• [AHPX](https://github.com/TylerLeonhardt/ahpx) — A command-line and Node.js client for connecting to AHP servers, managing sessions, and sending prompts.
• [VS Code](https://github.com/microsoft/vscode) — VS Code includes Agent Sessions client code for working with AHP hosts.

Servers

• [VS Code agent host](https://github.com/microsoft/vscode) — The reference AHP server implementation. Start in `src/vs/platform/agentHost/node/` when browsing the repository.

For consumers that need to talk to two or more hosts at once, the Rust SDK ships a MultiHostClient abstraction in `ahp::hosts`, the Swift SDK ships MultiHostClient in AgentHostProtocolClient, and the Go SDK ships MultiHostClient in [ahp/hosts](clients/go/ahp/hosts/). Single-host consumers use the same API via MultiHostClient::single in Rust, MultiHostClient.single(...) in Swift, or hosts.Single(...) in Go. See Connecting to Multiple Hosts for the design and surface.

Versioning and releases

Each language client and the spec itself release independently on their own SemVer tracks. See [docs/specification/versioning.md](docs/specification/versioning.md) for the protocol-level rules and [RELEASING.md](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