Zap! KiCad autorouter

npx add-mcp 'https://zap.mutual.solutions/mcp'

zap-pcb-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-pcb-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-pcb-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-pcb-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:

variable	meaning
ZAP_API_KEY	the key itself
ZAP_API_KEY_FILE	path to a file holding the key (default ~/.config/zap/key)
ZAP_URL	service address, default https://zap.mutual.solutions; must be https

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-pcb-mcp

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

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.

tool	key	what it does
check_board	yes	Pre-flight check (seconds, no routing, no job quota): every problem that would stop the job (blockers) and what would weaken it (warnings), with references, positions and the KiCad fix.
route_board	yes	Check, submit, wait, then save BOARD.routed.kicad_pcb, the full report BOARD.routed.zap-report.json, one SVG per copper layer and copies of BOARD.kicad_pro / .kicad_dru; then delete the server copy. An EasyEDA file with one PCB, a Standard PCB document (.json) or a Pro 3.x+ project (.epro, .epro2, .eprj), is sent alone and comes back as BOARD.routed.json / .epro (same format: your file plus only Zap!'s copper; rebuild the pours in EasyEDA before its DRC). If the reader found something it may have lost or changed, the board is still routed and easyeda_conversion_findings lists it. Projects saved by EasyEDA Pro 2.x are refused for now.
try_route_board	no	The same as route_board on the free trial (limits above). The trial deletes the job's files on the server right after the routed board is downloaded.
get_report	yes*	Every missing connection, design-rule error, JLC violation, hot spot and leftover copper, with position (mm), layer, net and what to do in KiCad.
get_job	yes*	Status and result numbers of a job; download_to saves the routed board.
list_jobs	yes	The key's last 50 jobs.
delete_job	yes	Cancel a queued or running job, or delete a finished job's files.
send_feedback	yes	Send the user's opinion to the Zap! team, only after the user approved the exact text (user_approved: true).
board_snapshot	yes	PNG of one square area (at most 40 mm) of a routed board with issues marked, returned as an image.
delete_snapshot	yes	Delete a picture the user does not want attached.
service_info	no	Service and router version, jobs waiting, typical routing time.
error_catalog	no	Every error code with its HTTP status, whether retrying helps and the fix.

* 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 $URL/v1/try/jobs answers with an id, a token (shown once) and the job's URLs (status_url, report_json_url, layer_svg_example_url, result_url); send the header X-Zap-Try-Token: <token> on each. POST /v1/check needs a key; the trial submission runs the same checks. Fetch report.json and the copper pictures it lists in image.layers[].url (/v1/try/jobs/$ID/report/F_Cu.svg, .../B_Cu.svg) 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.

field	meaning
unconnected	connections still missing (0 = fully routed)
critical_unconnected	of those, on supply, ground, clock, reset, boot or debug nets; must be 0 before ordering boards
drc_errors	KiCad design-rule errors under the uploaded rules (some come from the placement)
shorts	copper of two nets touching; Zap! never returns a board with a short it routed, so any here were already in the uploaded board (shorts_already_in_board)
jlc_violations (jlc_violations_by_type)	features JLCPCB's standard process cannot make, with positions in jlc_items
hottest_rise_c, sections_over_limit	hottest copper in °C above ambient, and copper sections over the limit (rise_limit_c, 10 °C)
currents	whether currents were estimated from the board's parts or stated by you (currents argument)

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.