zap-mcp

KiCad PCB autorouter for AI agents: MCP server, HTTP API and CLI, with a JSON manufacturability report (DRC, shorts, JLCPCB capability, copper heat).

zap-mcp is the stdio MCP server for Zap!, a hosted auto-router by mutual. You give it a placed .kicad_pcb (with its .kicad_pro); it returns the same board with tracks, vias and copper pours added, plus a report of what is still wrong and where. Node 18 or newer. The board is routed on the Zap! service, not on your machine.

Early access: every routed board must be reviewed by an engineer, and KiCad's DRC run, before fabrication.

Quick start

Claude Code

claude mcp add zap -e ZAP_API_KEY_FILE=$HOME/zap-key.txt -- npx -y zap-mcp

Restart the agent session: the tools appear only after the restart.

Claude Desktop, Cursor and other MCP clients

{
  "mcpServers": {
    "zap": {
      "command": "npx",
      "args": ["-y", "zap-mcp"],
      "env": { "ZAP_API_KEY_FILE": "/absolute/path/to/zap-key.txt" }
    }
  }
}

Claude Desktop: claude_desktop_config.json. Cursor: ~/.cursor/mcp.json or .cursor/mcp.json in the project.

The API key

Sign in at https://zap.mutual.solutions/auth/login and create an API key on your account page. Save it as ~/zap-key.txt and run chmod 600 ~/zap-key.txt. The server reads the key from the environment only, in this order:

The key is never taken from tool arguments and never written to tool output or logs. The server warns when the key file is readable by other users. Redirects are never followed, so the key is only sent to ZAP_URL.

No key: the free trial

Without a key, the try_route_board tool routes one small board with no sign-up: at most 300 pads, 2 or 4 copper layers, 2 trial jobs per network address per UTC day, stable router only. Every tool that needs a key answers, when none is set, with how to get one and that the trial exists.

claude mcp add zap -- npx -y zap-mcp

Then ask your agent to route a board, for example: "Route ~/boards/myboard.kicad_pcb with Zap!".

Related MCP server: worldbrain-mcp

Tools

The names, arguments and answers match the single-file Python server zap_mcp.py, so the guides at https://zap.mutual.solutions/agents.md apply to both.

* For a trial job, get_job and get_report work without a key in the same server session; after a restart pass the try_token that try_route_board returned.

check_board, route_board and try_route_board take every upload option of the API with the same name and default: project_path, rules_path, currents_path or currents, router (not on the trial), keep_existing, strip_existing, fab_floor, signal_width_mm, via_diameter_mm, via_drill_mm, vias_in_pads, ground_pour, size_rails_from_current, effort, minutes, consent_training. Boards are sent gzip-compressed.

HTTP API

Base URL https://zap.mutual.solutions, header Authorization: Bearer <key>. The key goes to curl as a header file, so it never appears in a command line:

URL=https://zap.mutual.solutions
zcurl() { curl -s -H @<(printf 'Authorization: Bearer %s\n' "$(cat "$ZAP_API_KEY_FILE")") "$@"; }

zcurl -F board=@myboard.kicad_pcb -F project=@myboard.kicad_pro $URL/v1/check            # check
zcurl -F board=@myboard.kicad_pcb -F project=@myboard.kicad_pro $URL/v1/jobs             # submit: {"id", "status": "queued"}
zcurl $URL/v1/jobs/$ID                                                                   # poll every 5 s until succeeded / failed / cancelled
zcurl -o myboard.routed.kicad_pcb $URL/v1/jobs/$ID/result                                # download (report: $URL/v1/jobs/$ID/report.json)

The trial without a key: curl -s -H 'X-Zap-Try: 1' -F board=@myboard.kicad_pcb -F project=@myboard.kicad_pro $URL/v1/try/jobs answers with an id and a token (shown once); read the job at /v1/try/jobs/$ID with the header X-Zap-Try-Token: <token>. Fetch report.json before result: the first download of the board deletes the job's files.

Every endpoint, field and error: openapi.json, llms.txt, error catalog, agent guide.

CLI

zap.py, Python 3.8 or newer, standard library only: python3 zap.py run myboard.kicad_pcb checks, submits, waits and saves the routed board and report, like route_board. python3 zap.py login signs in with OAuth instead of a key.

The report

All numbers count problems or temperatures: lower is better, 0 is best.

A result is ready for human review when the job succeeded, critical_unconnected is 0 and shorts is 0. It is clean when unconnected, drc_errors, jlc_violations and sections_over_limit are 0 as well. The saved BOARD.routed.zap-report.json lists every finding with at_mm (x, y in mm as KiCad shows them), layer, net and what_to_do.

Limits

• Free trial (no key): at most 300 pads, 2 or 4 copper layers, 2 jobs per network address per UTC day.

• With a key: up to 10,000 pads, 4,000 footprints, 2 to 16 copper layers, 20 MiB per upload (boards are sent compressed), 60 minutes per job, 2 jobs at a time and 30 requests a minute per key, daily jobs as issued with the key (default 50).

• A board too large for the self-serve service is refused with board_too_large; email hello@mutual.solutions to arrange a business (B2B) job.

• Early access: every routed board must be reviewed by an engineer, and KiCad's DRC run, before fabrication.

Benchmark

https://zap.mutual.solutions/compare

Privacy

What Zap! keeps from board files, why and for how long: https://zap.mutual.solutions/privacy. route_board deletes the server copy after download by default; trial jobs are deleted after the first download of the routed board.

Contact

hello@mutual.solutions

Licence

MIT, Copyright (c) 2026 Mutual Solutions, Inc. (see LICENSE). The licence covers this package, not the Zap! service; using the service is governed by https://zap.mutual.solutions/terms.