calibre-mcp

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Cover board data (widget-internal)

calibre_board_data

Read-only

Returns the cached payload of a recent Calibre search for the in-chat cover-board widget, letting the board display existing results without rerunning the query.

Instructions

Internal endpoint for the in-chat cover-board widget. Returns the cached payload of a recent search. Do not call as the model — search results already contain everything this returns.

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": "calibre_board_data"
  }
}

Input Schema

Name	Required	Description	Default
`tool`	No
`query`	No
`filter`	No
`library`	No

Output Schema

Name	Required	Description	Default
`kind`	No
`tool`	No
`books`	No
`query`	No
`total`	No
`libraryId`	No
`serverUrl`	No
`lowConfidence`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv0.10.0Oct 28, 2026
- addedInput schema / properties / filter
```
Added value: +{
+  "maxLength": 256,
+  "minLength": 1,
+  "type": "string"
+}
```
- addedInput schema / properties / library
```
Added value: +{
+  "type": "string"
+}
```
First observedv0.7.2Jul 29, 2026

TDQS

A4.1/5.0

Behavior3/5

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds useful context that the output is a cached payload served to a widget, but says nothing about cache staleness, freshness window, or what the payload contains beyond 'everything search returns'.

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?

Three short sentences, front-loaded with the identity of the endpoint, then the payload, then the do-not-call rule. No filler.

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?

An output schema exists so return values need no explanation, and the description fully accomplishes its main job of steering the model away from calling it. The only gap is undocumented parameters, which matters little given the explicit do-not-call instruction.

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?

All four parameters (tool, query, filter, library) have 0% schema description coverage, and the description does not explain any of them. Only a loose implication that query/filter mirror a prior search call; the meaning of 'tool' and 'library' is entirely undocumented.

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?

States a specific verb and resource ('internal endpoint for the in-chat cover-board widget... returns the cached payload of a recent search') and explicitly distinguishes itself from the search siblings whose results already contain this data. An agent instantly knows what it does and that it is out of scope.

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

Usage Guidelines5/5

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

Gives an explicit when-not: 'Do not call as the model — search results already contain everything this returns.' The alternative (the search tools) is named implicitly and unambiguously, leaving nothing to inference.

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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