About HCP
HCP is an open standard for installing capabilities into agent harnesses, developed in the open and changed only through public RFCs.
A capability ships as a Harness Pack, three files that name a CLI's commands, give each a Policy row and teach an agent to use them. The runtime checks the pack and the caller, mints credentials the pack never sees, sandboxes the command and refuses a risky write until a person agrees.
Agent Skills teach an agent how to behave and MCP carries tool calls between a model and a server; HCP installs the capability with its rules. Runtimes may be proprietary, but the pack format and the rules stay open.
Releases
| Part | Version | State | Date |
|---|---|---|---|
| Specification | HCP/1.1 | Draft | Open for RFCs |
| SDK and runtime | 0.3.0 | Private preview | 1 Nov 2026 |
| CLI and plugin | 0.2.0 | Private preview | 1 Nov 2026 |
| Protocol and SDK tag | v0.1.0 | Tagged | 17 Aug 2026 |
The roadmap lists what comes next, and Versioning explains how versions move.
Source
| Repository | Holds | Licence |
|---|---|---|
| hcp-protocol ↗ | The specification and the RFCs | Apache-2.0 |
| hcp ↗ | The CLI, SDK, runtime and gold packs | MIT |
| hcp-docs ↗ | This site and the pack catalog | Apache-2.0 |
Who runs it
The maintainers review RFCs and cut releases, and Governance explains how they decide. Until the project has its own legal entity, the company named in the imprint operates it and publishes this site. Any implementation claims conformance by passing the vectors in the specification.