check_clearance

THE RISK

Low Risk

Why check_clearance needs a policy

This tool queries and validates existing PCB design data against rules. It retrieves clearance information and produces a report, matching the Read category pattern of data retrieval with no side effects. No data is created, modified, deleted, or executed. The context (PCB design validation) and sibling tools (which add components, layers, etc.) confirm this is a diagnostic/verification function.

From the tool's definition Tool description states it 'Check[s] the actual clearance' and 'report[s] whether it meets the design rules' — purely informational operations with no modifications or side effects.

Documented attack patterns abuse exactly the kind of access check_clearance gives an agent:

POLICY

How to control check_clearance

PolicyLayer is an MCP gateway — it sits between your AI agents and KiCAD-MCP-Server, and nothing reaches the server without passing your rules. This is the rule we recommend for check_clearance:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "check_clearance": {}
  }
}

check_clearance is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register KiCAD-MCP-Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More KiCAD-MCP-Server tools

Destructive delete_component Remove a component from the PCB by its reference designator. Destructive delete_schematic_component Remove a placed symbol from a KiCAD schematic (.kicad_sch). This removes the symbol insta Destructive delete_schematic_net_label Remove a net label from the schematic. Destructive delete_schematic_wire Remove a wire from the schematic by start and end coordinates. Destructive delete_symbol Remove a symbol from a .kicad_sym library file. Destructive delete_trace Delete traces from the PCB. Can delete by UUID, position, or bulk-delete all traces on a n Destructive remove_schematic_component_property Remove a single custom property from a placed schematic symbol. Built-in fields (Referenc Execute autoroute Run Freerouting autorouter on the current PCB. Exports to Specctra DSN, runs Freerouting C

All 157 KiCAD-MCP-Server tools →

Read tools on other servers

M-Team MCP Server get_torrent_detail YouTube MCP Server search_channel Android Forensics ADB MCP Server parse_browser_history 0xarchive web3_challenge

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about check_clearance

What does the check_clearance tool do? +

Check the actual clearance between two PCB items (track, via, pad, zone or component) and report whether it meets the design rules. It is categorised as a Read tool in the KiCAD-MCP-Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on check_clearance? +

Register the KiCAD-MCP-Server MCP server in PolicyLayer and add a rule for check_clearance: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches KiCAD-MCP-Server. Nothing to install.

What risk level is check_clearance? +

check_clearance is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit check_clearance? +

Yes. Add a rate_limit block to the check_clearance rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block check_clearance completely? +

Set action: deny in the PolicyLayer policy for check_clearance. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides check_clearance? +

check_clearance is provided by the KiCAD-MCP-Server MCP server (mixelpixx/kicad-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every KiCAD-MCP-Server tool call.

Start from KiCAD-MCP-Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →