Imported from fireostendere/mcp_diptrace (skills/critical-net-router/SKILL.md). Install upstream with npx skills add fireostendere/mcp_diptrace --skill critical-net-router. Copyright stays with the author.

Read runtime access before choosing between explicit-path MCP, a live bridge session, and native/headless CLI. Their availability is separate.

Critical-net router

RAG: engineering memory by default — shared workflow. Consult routing/return-path and transmission-line material before choosing constraints; use DipTrace PCB courses for implementation and verify the actual route.

Route an explicitly named scope. The local router is deterministic bounded 45-degree A*, not push-and-shove. Use public tools/list for exact callable names and get_capabilities for document/configured feature availability.

Workflow

1. Call diptrace_status, get_capabilities, and get_document_info; require a PCB and freeze the SHA-256.
2. Read get_design_rules, list_unrouted_connections, and analyze_routing_congestion. Require concrete endpoints, allowed layers, via policy, and net or pair identity.
3. For one connection use route_connection; for exported ratlines use route_net. For a real pair use plan_diff_pair_route or route_diff_pair; never route the two legs independently.
4. Omit clearance only to resolve the document DRC TraceToTrace rule. An explicit caller value is millimetres and must be named in the report.
5. Prefer plan_route_nets plus apply_route_plan for a reviewable plan. Inspect SVG/JSON, then validate and use an expected_sha256 commit within the already authorized routing scope. A request for a plan alone never authorizes committing it.
6. Run run_drc and run_connectivity_check; rollback only this session's failed changes with a current hash guard. When native validation is in scope, use the headless PCB acceptance workflow; offline DRC does not invoke the real editor.
7. Emit ../shared/result.schema.json.

Quantitative boundaries

• One local route plan accepts at most 20 connections.
• route_connection defaults to zero vias, a 3.0 detour factor, and at most 100,000 search nodes.
• Multi-route rip-up/retry defaults to four attempts; this remains bounded local retry, not push-and-shove.
• A transaction accepts at most 100 operations and 500 conservatively counted affected objects/elements; this can be fewer than 500 unique physical objects.

The limits and defaults are implemented in server.py, service.py, routing.py, and write_limits.py. Runtime capabilities win.

Refusals

• Stop when pad endpoints, layer span, applicable clearance, or allowed via style is unresolved.
• Stop when an existing route contains arcs or jumpers that the requested rewrite cannot preserve.
• Do not describe congestion score as calibrated engineering risk.
• Do not use the external autorouter unless its DSN/SES geometry and job provenance gates succeed.

Search ranking is heuristic; exact rules, route geometry, preview, and post-checks are document.