Interactive reference model

Talk to a mock OpenMHS endpoint

A deterministic conveyor workcell in your browser. Send JSON-RPC requests, watch receipts, open an interlock, reuse a command id, latch an e-stop and export the evidence chain. Nothing leaves this page.

Reference model — not a real deviceNo network requestsState resets on reload

This is a teaching model.

It implements a deliberately small, readable subset of OpenMHS to show command semantics. It is not conformance-tested, not a safety-rated channel, and not connected to equipment. Do not use it to drive anything physical.

Request

Discovery

Observe

Act

Safety

Evidence

{
  "jsonrpc": "2.0",
  "id": "req-hello",
  "method": "mhs.hello",
  "params": {
    "client": {
      "name": "mhs-playground",
      "version": "1.0"
    },
    "protocol_versions": [
      "1.0"
    ],
    "features": [
      "batch"
    ]
  }
}

Edit the JSON directly. The mock understands mhs.hello, devices.list, devices.get, resource.read, command, safety.status, safety.estop, safety.reset, session.open and evidence.export.

Response

Ready.

mhs.hello — simulated

{}

Endpoint state

live

Tick0ms simulated

Revision7monotone uint64

Doorclosedinterlock

E-stopreleasedlatched when engaged

Parts1on the conveyor

Evidence0receipts chained

Operator controls (outside OpenMHS)

The door is a physical interlock. Toggling it changes the world but is not an OpenMHS command; the next command is refused while it is open.

Session log

A local trace of requests and state changes. It is not the evidence chain; use Export evidence for that.

What to try

A five-minute tour of the contract

Discover

Send Hello and inspect endpoint_id, limits, features and the MHS.SAFETY.NOT_CERTIFIED disclosure.

Observe

Read the workcell and compare the revision and state_hash before and after a command.

Refuse

Open the door, then send a command. The receipt is rejected with MHS.SAFETY.INTERLOCK_OPEN; the revision does not advance.

Account

Export the evidence bundle. Every receipt is chained; a rejected action is evidence, not an exception.