canforge-mcp

canforge-mcp is a local, read-only MCP server for inspecting DBC files and decoding CAN capture logs.

Files stay on the machine running the server. The server exposes bounded tools instead of uploading captures or returning unbounded traces.

Tools

Tool	Purpose
dbc_info	DBC version, message/signal/node counts, and node names
list_messages	Bounded message summaries, with optional search
get_message	Full message and signal detail by name or arbitration ID
search_signals	Bounded signal search across a DBC
decode_frame	Decode one hexadecimal CAN payload
validate_dbc	Structured DBC validation issues
diff_dbcs	Added, removed, and changed messages and signals
probe_log	Detect a log format and read header metadata
log_stats	Frame count, span, ID counts, and median cycle times
read_frames	Bounded raw-frame samples with ID and time filters
decode_log	Bounded decoded frames from a DBC and log
signal_timeseries	Downsampled timestamp/value points for one signal

See the tool reference for arguments, return shapes, and hard caps.

Install

Run directly with uvx:

uvx canforge-mcp

Or install with pip:

pip install canforge-mcp
canforge-mcp

Requires Python >=3.11.

Configure

Claude Code:

claude mcp add canforge -- uvx canforge-mcp

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "canforge": {
      "command": "uvx",
      "args": ["canforge-mcp"]
    }
  }
}

Restart the client after changing its MCP configuration.

Design

• Local-first: tools accept filesystem paths and do not send file content over the network.
• Read-only: no tool creates, edits, encodes, or overwrites a file.
• Bounded: list and frame tools enforce hard caps and report total, returned, and truncated; timeseries are downsampled server-side.
• Cached: parsed DBCs are cached by resolved path and nanosecond modification time for repeated inspection during one server session.
• Composable: capkit reads capture formats; dbckit parses and decodes DBC content.
• Stdio-only: version 0.1 exposes no network transport or hosted service.

Scope and Caveats

• Supported capture formats come from capkit 0.2: Kvaser CanKing TXT, candump text, and Vector ASC.
• DBC support and validation behavior follow dbckit 1.x.
• Timestamps are floats exactly as recorded by capkit; they are not rebased.
• Median cycle time is the median gap between consecutive occurrences of an ID.
• signal_timeseries uses deterministic, evenly spaced index sampling when a series exceeds max_points; it is intended for inspection, not resampling or signal processing.
• Paths are resolved by the machine running the MCP server. A remote client's filesystem is not visible to a server running elsewhere.

Development

python -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"
ruff check .
mypy canforge_mcp
pytest --cov=canforge_mcp --cov-fail-under=90
python -m build

License

MIT