brontes-probe-mcp 0.2.2

Multi-client debug-probe broker MCP server — session lifecycle, probe operations, ITM/SWO trace, and lane supervision over three concurrent transports

brontes-probe-mcp

A Model Context Protocol (MCP) server that gives AI assistants direct access to a debug probe — flash firmware, halt/resume, read memory, and stream ITM trace, all without leaving the conversation.

Status: 0.2.2 — fully operational. Session lifecycle, probe operations, ITM/SWO trace, and lane supervision over three concurrent transports (stdio MCP, Unix socket, loopback TCP).

Quick start

Three steps: configure, start the probe agent (macOS / pip only), connect.

---

Step 1 — Configure

Pick your deployment. Each section below includes a prompt you can paste directly into Claude Code to write .mcp.json automatically, or add it manually if you prefer.

Docker on Linux (recommended)

Paste into Claude Code:

Add brontes-probe-mcp to .mcp.json in this project, creating it if needed:

{
  "mcpServers": {
    "brontes-probe-mcp": {
      "command": "docker",
      "args": [
        "run", "--rm", "-i",
        "--device=/dev/bus/usb",
        "-v", "${HOME}/.brontes-probe-mcp:/run/brontes-probe-mcp",
        "-v", "${HOME}/.brontes-probe-mcp/packs:/packs",
        "-e", "PROBE_BROKER_TRANSPORTS=stdio,socket",
        "-e", "CMSIS_PACK_ROOT=/packs",
        "ghcr.io/cms-pm/brontes-probe-mcp@sha256:61e4d0423085ac734a938b2a45a984e5197e1803326547f5d13d519e67798e91"
      ]
    }
  }
}

Then pull the image:
docker pull ghcr.io/cms-pm/brontes-probe-mcp@sha256:61e4d0423085ac734a938b2a45a984e5197e1803326547f5d13d519e67798e91

Then tell me to restart Claude Code to load the new server.

Replace sha256:61e4d0423085ac734a938b2a45a984e5197e1803326547f5d13d519e67798e91 with the digest from CHANGELOG.md.

Docker on macOS (Docker Desktop)

Docker Desktop cannot pass USB devices into containers. First install the host CLI:

pip install brontes-probe-mcp

Paste into Claude Code:

Add brontes-probe-mcp to .mcp.json in this project, creating it if needed:

{
  "mcpServers": {
    "brontes-probe-mcp": {
      "command": "docker",
      "args": [
        "run", "--rm", "-i",
        "-v", "${HOME}/.brontes-probe-mcp:/run/brontes-probe-mcp",
        "-v", "${HOME}/.brontes-probe-mcp/packs:/packs",
        "-e", "PROBE_BROKER_TRANSPORTS=stdio,socket",
        "-e", "CMSIS_PACK_ROOT=/packs",
        "-e", "PROBE_BROKER_GDB_HOST=host.docker.internal",
        "ghcr.io/cms-pm/brontes-probe-mcp@sha256:61e4d0423085ac734a938b2a45a984e5197e1803326547f5d13d519e67798e91"
      ]
    }
  }
}

Then tell me to restart Claude Code to load the new server.

pip install (no Docker, all platforms)

Requires arm-none-eabi-gdb on PATH (install via your OS package manager or ARM toolchain download).

pip install brontes-probe-mcp

Paste into Claude Code:

Add brontes-probe-mcp to .mcp.json in this project, creating it if needed:

{
  "mcpServers": {
    "brontes-probe-mcp": {
      "command": "brontes-probe-mcp-cli",
      "args": ["serve"]
    }
  }
}

Then tell me to restart Claude Code to load the new server.

---

Step 2 — Start the probe agent (macOS and pip only)

Docker on Linux users skip this step — the container manages pyocd internally.

Run this once before each session (keep it running in the background):

# Auto-detects probe and target if exactly one probe is connected
brontes-probe-mcp-cli probe-agent start

If auto-detection fails (multiple probes, or board not recognised by pyocd):

brontes-probe-mcp-cli probe-agent start --target stm32g474 --probe-uid <uid>

session_start auto-discovers the running agent — no extra configuration needed. session_stop removes the Brontes session but leaves the agent running for reuse.

---

Step 3 — Connect

After restarting Claude Code (or running /mcp to reload), paste this into the conversation:

Call probe_discover to list connected debug probes. Use any board or chip
information from the results to call target_suggest and find the pyocd
target string. If target_suggest returns no matches, call pack_update to
refresh the pack index, then pack_search to find the right CMSIS pack name,
then pack_install (may take a minute), then retry target_suggest. Once you
have the target string, call session_start — omit probe_uid if only one
probe is connected, otherwise pass the uid from probe_discover.

If you already know your target string:

Call session_start with target="stm32g474".

---

What it does

• Probe discovery — probe_discover, target_suggest, pack_search, pack_install, pack_update
• Session lifecycle — session_start, session_stop, session_status (reports image_digest, image_tag, protocol_version).
• Probe operations — probe_program (elf / bin / hex), probe_halt, probe_resume, probe_reset (soft / hard), probe_mem_read, probe_blackbox_export.
• ITM / SWO trace — itm_stream_start, itm_stream_stop, recent_lines.
• Lane supervision — lane_status, lane_release, lane_resume.

Three transport adapters bind concurrently over one shared BrokerCore instance, controlled by PROBE_BROKER_TRANSPORTS:

Transport	Default	Use case
stdio	✓	MCP stdio — one AI client
socket	✓	Unix-domain socket — local tool access
tcp	—	Loopback TCP with bearer token — sandbox / Docker Desktop

CLI

The brontes-probe-mcp-cli console script manages the server and probe agent:

brontes-probe-mcp-cli --version
brontes-probe-mcp-cli --config-dump            # print resolved config as JSON

# Start all configured transports (MCP server entry point for pip install)
brontes-probe-mcp-cli serve

# Probe agent — manages the host-side pyocd gdbserver daemon
brontes-probe-mcp-cli probe-agent start [--target TARGET] [--port PORT] [--probe-uid UID]
brontes-probe-mcp-cli probe-agent status       # prints JSON; exits 1 if not healthy
brontes-probe-mcp-cli probe-agent stop [--force]

If --target is omitted, probe-agent start auto-detects from a connected probe. If multiple probes are attached, specify --target and --probe-uid.

Configuration

All configuration is via PROBE_BROKER_* environment variables:

Variable	Default	Description
PROBE_BROKER_TRANSPORTS	stdio,socket	Comma-separated active transports
PROBE_BROKER_SOCKET_PATH	~/.brontes-probe-mcp/probe.sock	Unix socket path
PROBE_BROKER_TCP_HOST	127.0.0.1	TCP bind address
PROBE_BROKER_TCP_PORT	7172	TCP port
PROBE_BROKER_LANES	swd,itm_swo	Active probe lanes
PROBE_BROKER_BACKEND	pyocd	Debug backend (pyocd or openocd)
PROBE_BROKER_GDB_HOST	127.0.0.1	GDB server host — set to host.docker.internal to connect to a host-side probe agent
PROBE_BROKER_DEFAULT_PACK	(none)	Default CMSIS pack path — used by target_suggest and session_start when no pack= argument is supplied
PROBE_BROKER_AGENT_STATE_DIR	~/.brontes-probe-mcp	Directory where probe-agent start writes its state file and where session_start looks for a running agent. If probe-agent start --state-dir is set to a non-default path, set this variable to match
PROBE_BROKER_DIGEST_CHECK	enforce	Image digest verification (enforce, warn, skip)

Flash memory snapshot (probe_blackbox_export)

Capture a binary snapshot of the target's flash for archiving or diff:

{
  "tool": "probe_blackbox_export",
  "arguments": {
    "out": "/tmp/snapshot.bin"
  }
}

Defaults to 0x08000000–0x08080000 (512 KB). Requires an active session. Response includes bytes_written and snapshot_at (UTC ISO-8601).

See docs/tutorials/blackbox-export.md for custom address ranges, error cases, and snapshot comparison examples.

Advanced deployment

Docker Compose (socket, auto-restart)

curl -fsSL https://raw.githubusercontent.com/cms-pm/brontes-probe-mcp/main/docker-compose.yml \
  -o docker-compose.yml
docker compose up -d

TCP loopback (sandbox / Docker Desktop without probe-agent)

docker run -d --name brontes-probe-mcp \
  -e PROBE_BROKER_TRANSPORTS=stdio,tcp \
  -e PROBE_BROKER_TOKEN=your-token-here \
  -p 127.0.0.1:7172:7172 \
  --device=/dev/bus/usb \
  ghcr.io/cms-pm/brontes-probe-mcp:0.2.2

Pinning by digest

Pin by digest for production — the digest is the binary-level reproducibility contract:

ghcr.io/cms-pm/brontes-probe-mcp@sha256:<digest>

Digests are published in CHANGELOG.md for each release.

Client configuration

Configure your AI client to launch the server via the MCP stdio transport.

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (Linux: ~/.config/Claude/claude_desktop_config.json):

{
  "brontes-probe-mcp": {
    "command": "docker",
    "args": [
      "run", "--rm", "-i",
      "--device=/dev/bus/usb",
      "-v", "${HOME}/.brontes-probe-mcp:/run/brontes-probe-mcp",
      "-v", "${HOME}/.brontes-probe-mcp/packs:/packs",
      "-e", "PROBE_BROKER_TRANSPORTS=stdio,socket",
      "-e", "CMSIS_PACK_ROOT=/packs",
      "ghcr.io/cms-pm/brontes-probe-mcp@sha256:61e4d0423085ac734a938b2a45a984e5197e1803326547f5d13d519e67798e91"
    ]
  }
}

macOS users: omit --device=/dev/bus/usb and add "-e", "PROBE_BROKER_GDB_HOST=host.docker.internal" after running brontes-probe-mcp-cli probe-agent start on the host.

Claude Code

Add to .mcp.json in your project root (or ~/.claude.json for global config):

{
  "mcpServers": {
    "brontes-probe-mcp": {
      "command": "docker",
      "args": [
        "run", "--rm", "-i",
        "--device=/dev/bus/usb",
        "-v", "${HOME}/.brontes-probe-mcp:/run/brontes-probe-mcp",
        "-v", "${HOME}/.brontes-probe-mcp/packs:/packs",
        "-e", "PROBE_BROKER_TRANSPORTS=stdio,socket",
        "-e", "CMSIS_PACK_ROOT=/packs",
        "ghcr.io/cms-pm/brontes-probe-mcp@sha256:61e4d0423085ac734a938b2a45a984e5197e1803326547f5d13d519e67798e91"
      ]
    }
  }
}

Codex

Add to ~/.codex/config.json:

{
  "mcpServers": {
    "brontes-probe-mcp": {
      "command": "docker",
      "args": [
        "run", "--rm", "-i",
        "--device=/dev/bus/usb",
        "-v", "${HOME}/.brontes-probe-mcp:/run/brontes-probe-mcp",
        "-v", "${HOME}/.brontes-probe-mcp/packs:/packs",
        "-e", "PROBE_BROKER_TRANSPORTS=stdio,socket",
        "-e", "CMSIS_PACK_ROOT=/packs",
        "ghcr.io/cms-pm/brontes-probe-mcp@sha256:61e4d0423085ac734a938b2a45a984e5197e1803326547f5d13d519e67798e91"
      ]
    }
  }
}

OpenCode

Add to opencode.json in your project root:

{
  "mcp": {
    "servers": {
      "brontes-probe-mcp": {
        "type": "stdio",
        "command": "docker",
        "args": [
          "run", "--rm", "-i",
          "--device=/dev/bus/usb",
          "-v", "${HOME}/.brontes-probe-mcp:/run/brontes-probe-mcp",
          "-v", "${HOME}/.brontes-probe-mcp/packs:/packs",
          "-e", "PROBE_BROKER_TRANSPORTS=stdio,socket",
          "-e", "CMSIS_PACK_ROOT=/packs",
          "ghcr.io/cms-pm/brontes-probe-mcp@sha256:61e4d0423085ac734a938b2a45a984e5197e1803326547f5d13d519e67798e91"
        ]
      }
    }
  }
}

Replace sha256:61e4d0423085ac734a938b2a45a984e5197e1803326547f5d13d519e67798e91 with the pinned digest from CHANGELOG.md.

Why "Brontes"

Brontes ("Thunderer") is one of the cyclops smiths in Hephaestus's forge — the worker who hammers metal at the master's direction. The metaphor maps onto the broker's role: client code directs the operation, the broker performs the probe work.

Changelog

See CHANGELOG.md.

License

Apache-2.0. See LICENSE.