MCP server & tools

Hard Fault ships a local MCP server that exposes board control as tools. The turnkey brain talks to it directly (it launches the server as a subprocess), and you can also point your own MCP client at the same surface.

Start the server

uv run pyocd-debug-mcp

With a board id set, the server resolves that board’s facts — target, recover policy, silicon id, baud — from boards/<board>.yaml, so connect needs no raw target and get_board_info reports the loaded facts.

Tool surface

The current tools, all live-validated on the scoped boards:

Session — connect, disconnect, get_board_info, get_state
Execution control — halt, resume, step, reset
Registers & memory — read_core_register, write_core_register, read_memory, read_memory_block, write_memory
Breakpoints — set_breakpoint, remove_breakpoint
Firmware & serial — flash_firmware, read_serial
Recovery — unlock_recover

connect(...) creates a visible session_id, and each run writes runs/<session_id>/logs/events.jsonl plus runs/<session_id>/run-metadata/session.json for inspection.

Guardrails

Mutating tools are gated. See Guardrails for how flash and recover gates and the mutation watchers behave.