Reference

The reference section is the implementation entry point. Use it when you already understand the protocol model and need exact surfaces: HTTP paths, MCP tools, interoperability status, SDK calls, and generated artifacts.

OpenAPI 3.1 contract, live endpoint, and committed snapshot.

REST API

Streamable HTTP transport and tool surface.

MCP

Legacy experimental endpoint, current compatibility limits, and migration target.

A2A integration status

@grp-protocol/sdk client, examples, and receipt verification helpers.

TypeScript SDK

Version

The current protocol version is grp/0.2, which inherits the frozen 0.1 base and adds the versioned coordination contract. The published OpenAPI snapshot covers the base REST operations. Pin integrations to the applicable contracts and check the host’s capabilities; main need not match a deployed host.

Source of Truth

The base REST contract is the OpenAPI document. The SDK examples are typechecked. Base conformance profiles test the same decision lifecycle through REST and MCP.

Actions, artifacts and review

Work operations have a separate actions/artifacts contract and coordination support matrix. They are available through REST with participant tokens, the CLI and the hosted account MCP connection. The base OpenAPI snapshot, token-based MCP catalogs and SDK have narrower coverage. Start with actions for the model, then use the contract or account MCP help for exact inputs, transitions and errors.