Bibooks

Search audiobooks

search_books

Read-onlyIdempotent

Search the public library of bilingual audiobooks. All filters are optional; values within one filter are OR'd, different filters are AND'd. With no arguments, lists every public book, easiest first. Returns one page of books (see has_more and page) with each book's id, title, author, languages, CEFR level, length and links. Language filters take content-language codes from list_languages (e.g. 'es', 'zh', 'fil').

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": "search_books"
  }
}

Input Schema

Name	Required	Description	Default
`page`	No	Page number, starting at 1.
`sort`	No	Result order.	easiest
`level`	No	CEFR levels to include.
`query`	No	Text to find in titles and authors.
`origin`	No	Text origins to include.
`audience`	No	Audiences to include.
`duration`	No	Audio length buckets to include.
`page_size`	No	Books per page.
`source_language`	No	Languages the books' original text is written in, i.e. the learner's language.
`target_language`	No	Languages the books are translated into, i.e. the language being learned.

Output Schema

Name	Required	Description
`page`	Yes	This page's number, starting at 1.
`items`	Yes
`total`	Yes	Number of books matching the filters, across all pages.
`has_more`	Yes	Whether a further page exists.
`page_size`	Yes	Maximum number of items per page.

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedOct 28, 2026

removedInput schema / $defs / Sort

Removed value: -{
-  "description": "Result order. `easiest`: CEFR level easiest first, unlevelled books last, highest score within a level (the default, and the order of the public library on the website). `recent`: newest first. `top_rated`: highest score first. `controversial`: most votes first. `length_asc` / `length_desc`: by audio duration.",
-  "enum": [
-    "easiest",
-    "controversial",
-    "length_asc",
-    "length_desc",
-    "recent",
-    "top_rated"
-  ],
-  "title": "Sort",
-  "type": "string"
-}

removedInput schema / properties / sort / $ref
```
Removed value: -"#/$defs/Sort"
```

addedInput schema / properties / sort / enum

Added value: +[
+  "easiest",
+  "controversial",
+  "length_asc",
+  "length_desc",
+  "recent",
+  "top_rated"
+]

addedInput schema / properties / sort / type
```
Added value: +"string"
```

First observedOct 26, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so safety is covered; the description adds real behavioral context beyond that: pagination via has_more and page, default 'easiest first' ordering, and a dependency on list_languages for valid codes. Minor redundancy in enumerating return fields that the output schema already defines.

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

Conciseness4/5

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

Four tight sentences, front-loaded with purpose and scope, no filler. The sentence enumerating returned fields is slightly wasteful given an output schema exists, but it is short.

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

Completeness5/5

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

For a 10-parameter, all-optional search tool with full schema coverage and an output schema, nothing critical is missing: filter combination logic, empty-argument behavior, ordering, pagination and language-code sourcing are all stated.

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 description coverage is 100%, so the baseline is 3; the description adds meaning beyond it by defining multi-value OR semantics per filter and the AND relationship across filters. It also points at list_languages for valid language codes, though it does not clarify source_language vs target_language, which only the schema labels cover.

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 opens with a specific verb and resource: 'Search the public library of bilingual audiobooks', and clarifies the no-argument behavior ('lists every public book'). It stops short of naming siblings like get_book or find_related_books, so differentiation is inferred rather than stated.

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?

It explains how filters combine ('values within one filter are OR'd, different filters are AND'd') and what happens when no filters are supplied, which is exactly the guidance an agent needs. It does not, however, say when to prefer a sibling such as get_book for a known id, or find_related_books for recommendations.

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

All Bibooks tools Inspect

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