kicad-mcp currently autoroutes by shelling out to freerouting.jar, which drags in a JVM dependency. freeroute reimplements the routing engine in pure Python so the toolchain needs no Java at all.

The contract

The entire integration surface is two Specctra files:

board.dsn  ──▶  freeroute  ──▶  board.ses
(unrouted)                       (routed session: traces + vias)

kicad-cli already exports .dsn and imports .ses, so freeroute is a drop-in replacement for the JAR step — nothing else in the pipeline changes.

Status

Pre-alpha. Under active development. See docs/PORTING_PLAN.md for the architecture and porting roadmap.

Usage (target)

freeroute board.dsn -o board.ses

Development

uv sync
uv run pytest
uv run ruff check src/ tests/

License

GPL-3.0-or-later, matching the FreeRouting source it is ported from.