What it is
OpenCastor is the open-source robotics edition of PlatAtlas. It is how a robot describes itself and how any agent safely drives it, built on the same idea as the platform: describe the work declaratively, sign what actually happens, keep a record anyone can replay.
At its center is one file. ROBOT.md is to a robot what CLAUDE.md is to a codebase: a single declarative manifest at the root of the robot’s project that lets Claude Code, Claude Desktop, Cursor, or any MCP-aware agent understand and operate the machine. Everything else in the stack reads or writes that file.
Explore the full ecosystem → craigmerry.com/ecosystem
The stack
Four layers, each its own repo with its own release cadence and one clear concern:
- Surfaces are how agents touch the robot: an MCP server, a BYOK Claude Agent SDK dispatcher over HTTPS, a Claude Code plugin marketplace, and a touchscreen-plus-voice pendant on a Raspberry Pi.
- Manifest is
robot-md: the ROBOT.md spec, validator, and CLI, with over 1,100 tests. - Protocol is RCAN: canonical-JSON sign and verify, capability descriptors, and safety semantics, with official Python and TypeScript SDKs.
- Registry is the Robot Registry Foundation: per-robot and per-model identity, Ed25519-signed registrations, and the first five EU AI Act-aligned compliance endpoints, live.
Proof it runs
The hardware in the loop is bob, a SO-ARM101 arm and a depth camera on a Raspberry Pi 5, registered as RRN-000000000001. Bob runs an autonomous vision pick-and-place: it finds a red brick by camera, plans the grasp, and places it in the bowl, with no teleoperation and no hand-coded coordinates. Every feature is exercised against real servos before it merges. The whole ecosystem is Apache-2.0 and built by pairing with Claude Code.