Changelog

10.1 v0.1 (draft)

The first draft of the OpenHAL specification, dated 2026-10-24.

On 2026-10-28 the draft dated 2026-10-24 became v0.1, because versions are now numbered MAJOR.MINOR (ADR 0017). The requirements did not change.
hal/initialize negotiates 0.1. A protocolVersion that is not in the form MAJOR.MINOR, such as a date, gets INVALID_PARAMS (-32602) with a reason that names the supported versions.
The draft moved from its dated folder to spec/v0.1/.

JSON-RPC 2.0 messages over WebSocket at /rpc and over stdio through openhal rpc.
Initialization with version negotiation, hal/initialized and hal/shutdown.
Core methods hal/initialize, hal/devices/list, hal/devices/describe, hal/read and hal/readMany.
Control methods hal/write, hal/dryRun, hal/planCheck, hal/stop and hal/unlock.
Full methods hal/action, hal/confirmations/list, hal/confirmations/approve, hal/confirmations/reject, hal/routines/list, hal/routines/dryRun and hal/audit/query.
Notifications hal/value, hal/blocked, hal/stopped, hal/deviceAdded, hal/deviceRemoved and hal/confirmationRequested.
The error registry, codes -32700 to -32603 and -32001 to -32023, with one registry name per Safety Kernel code.
Conformance Levels core, control and full for Hubs and Drivers.

Identity and library matching (device, id, match).
Driver selection with shorthand (connect).
Read channels, write channels with min, max, step, rate and enum limits, and actions with typed arguments, requirements and run limits.
Safe state as values, an action, or ordered steps.
Interlocks and the expression language, with three-valued evaluation where unknown never passes.
Watchdog heartbeat, loss behavior and max duration rules.
Hazard classes and human-signed approvals for routines on high hazard Devices.
Notes as data, provenance and verification status.
Limits provenance. Files load read-only until a human confirms every limit.

The Safety Kernel check order, unknown values, Grants, confirmations, stop and unlock.
YAML and Python routines that run through the Safety Kernel and start disabled.
Local-only network exposure by default, human and agent tokens, and text from Devices handled as data.