circuitarium-mcp

Overview Schema Source Related Servers Discussions Admin

Look up CRUMB IC packages and pinouts

crumb_ic_reference

Read-onlyIdempotent

Query the IC registry by prefab ID or label substring to retrieve package labels, ordered pin names, and unresolved pins for circuit analysis.

Instructions

Queries the version-pinned tool-5 IC registry by prefabId or by a label/package substring (for example "74HC138"). Returns package labels, ordered pin names, and explicit unresolved pins.

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": "crumb_ic_reference"
  }
}

Input Schema

Name	Required	Description	Default
`query`	No	Case-insensitive substring matched against IC label and package name
`prefabId`	No

Output Schema

Name	Required	Description	Default
`ok`	Yes
`data`	No
`error`	No
`context`	Yes
`summary`	Yes
`diagnostics`	Yes
`nextActions`	Yes
`contractVersion`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.1Jul 31, 2026

TDQS

A3.9/5.0

Behavior4/5

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

The description adds context beyond the annotations: it notes the registry is 'version-pinned' (reproducible), pin names are 'ordered', and 'explicit unresolved pins' are returned, which is a valuable edge-case disclosure. These complement the readOnlyHint and idempotentHint annotations rather than contradict them. The example query also gives a concrete feel for behavior, though it stops short of describing error handling or interaction of both params.

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 long, front-loaded with the core action, and includes an illustrative example. Each sentence adds distinct value: the first explains the query modes and registry pinning, the second details the return fields. There is no extraneous text or repetition.

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 lookup tool with two optional parameters and an output schema, the description covers the essential usage: query modes, example, and return structure. The version-pinning note adds reproducibility context. Missing are explicit alternatives/usage boundaries and error/edge-case handling (e.g., no matches, both params given), but these are secondary given the annotations and output schema.

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

Parameters4/5

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

Schema coverage is only 50% (query has a description, prefabId does not). The description compensates by explaining both parameters: query is matched as a 'label/package substring' and prefabId is the alternative lookup mode. It also provides a concrete example ('74HC138') that clarifies the substring semantics. However, it does not specify what happens when both parameters are provided, how prefabId is formed, or precedence between them, leaving some ambiguity.

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 specifies the verb 'Queries', the resource 'version-pinned tool-5 IC registry', and the exact inputs (prefabId or label/package substring) and outputs (package labels, ordered pin names, explicit unresolved pins). It clearly states what the tool does without being tautological. However, it does not explicitly differentiate from sibling tools like crumb_get_component or crumb_component_catalog, which may also retrieve component data.

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

Usage Guidelines3/5

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

The intended use is implied by the title and description (looking up IC packages/pinouts), and the query modes are stated. However, there is no explicit when-to-use vs. alternatives, no mention of preferred scenarios, and no explanation of edge cases like multiple matches or empty results. The guidance is implied rather than explicit.

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