Agent Host Protocol
A synchronized, multi-client state protocol for AI agent sessions.
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:previewLicense
MIT