ltspice-mcp

diff_circuit

Read-onlyIdempotent

Compare two circuit files to identify differences in components, values, attributes, and directives, verifying changes after edits.

Instructions

Structural diff between two circuit files: reports added/removed components, components whose value or attributes (Value2/SpiceLine/SpiceModel) changed, and added/removed .PARAM/.MEAS/.MODEL directives. Use after set_component_value, set_component_attribute or edit_directive to confirm that the intended change actually landed.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "path_a": "<path_a>",
      "path_b": "<path_b>"
    },
    "name": "diff_circuit"
  }
}

Input Schema

Name	Required	Description
`format`	No	Response format: 'json' for structured data, 'text' for human-readable
`path_a`	Yes	Path to the first circuit file (.cir, .net, or .asc)
`path_b`	Yes	Path to the second circuit file (.cir, .net, or .asc)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 21, 2026

TDQS

A4.2/5.0

Behavior4/5

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

With annotations already declaring readOnlyHint=true, idempotentHint=true, and destructiveHint=false, the safety profile is covered. The description adds meaningful behavioral detail beyond that by specifying the categories of changes detected (components, attributes, .PARAM/.MEAS/.MODEL directives), giving the agent a concrete sense of the tool's output scope.

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?

The description is two sentences, front-loaded with the core purpose in sentence one and usage context in sentence two. Every word contributes value; no fluff or repetition of the schema. This is a model of efficient tool description.

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

Completeness4/5

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

For a read-only diff tool with no output schema, the description provides the key output categories and a usage trigger, which gives the agent enough context to invoke it correctly. It does not describe exact return formatting, but the format parameter and listed report categories cover the essentials, leaving only minor gaps.

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

Parameters3/5

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

Schema description coverage is 100%, so the schema already fully documents path_a, path_b, and format. The description adds little parameter-specific semantic beyond implying two file paths; it focuses on the diff behavior rather than explaining the parameters, so the baseline score of 3 is appropriate.

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

Purpose5/5

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

The description opens with the specific verb 'diff' and names the resource ('two circuit files'), then enumerates exactly what it reports: added/removed components, changed values/attributes, and added/removed directives. This clearly distinguishes it from sibling tools like read_circuit or validate_netlist, which serve different purposes.

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

Usage Guidelines4/5

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

The second sentence explicitly tells the agent when to use this tool: after set_component_value, set_component_attribute, or edit_directive, to confirm a change landed. This is clear context, though it stops short of naming when-not-to-use or alternative diff tools, so it earns a 4 rather than a 5.

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