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pcb_set_design_rules

Destructive

Write board-level manufacturing constraints into the active .kicad_dru file, setting minimum clearance, trace width, via drill, annular ring, and hole spacing for PCB fabrication.

Instructions

Write board-level manufacturing constraints into the active .kicad_dru file.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "pcb_set_design_rules"
  }
}

Input Schema

Name	Required	Description	Default
`min_clearance_mm`	No
`min_via_drill_mm`	No
`min_trace_width_mm`	No
`min_annular_ring_mm`	No
`min_hole_to_hole_mm`	No
`min_via_diameter_mm`	No

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.3.2Aug 7, 2026

TDQS

C2.8/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare destructiveHint=true, and the description says 'Write', which is consistent but not contradictory. However, the description does not disclose the scope of the write (e.g., overwrites all existing rules), whether unspecified parameters are reset to defaults, or if the file is saved immediately. This adds minimal value beyond the destructive hint.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single, grammatically complete sentence that is compact and front-loaded. Every word contributes to stating the tool's purpose without redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Even with an output schema and destructiveHint annotation, the description lacks essential context for a mutation tool. It does not explain what happens to existing design rules, how defaults are applied, or whether an active board is required. This is incomplete for a tool that modifies persistent state.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema has 0% description coverage, and the description does not compensate by explaining any of the six parameters. While parameter names like 'min_clearance_mm' are self-explanatory, the description itself adds no meaning beyond saying 'manufacturing constraints'. This is insufficient for low coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Write') and the target resource ('board-level manufacturing constraints into the active .kicad_dru file'). This is specific enough to understand the tool's function. However, it does not explicitly differentiate from sibling tools like drc_rule_create or pcb_get_design_rules, though the name and context provide some distinction.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives. There is no mention of prerequisites, whether it should be used before manufacturing, or any exclusions. The only implied context is that it writes to the active design rules file, but no explicit usage direction is given.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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