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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds useful context beyond annotations: the corpus is indexed public-domain books, results include title/author/snippet, and search can be narrowed to one book. No contradiction with annotations.

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

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

Three sentences with the action verb front-loaded ('Search INSIDE...'). The phrase 'headline feature' adds minor positioning context, but every sentence otherwise earns its place without redundancy.

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

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

With no output schema, the description covers the return shape (matching passages with title, author, snippet) and the scope of the corpus. It does not mention no-results behavior or pagination, but limit defaults are documented in the schema and the overall behavior is clear.

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

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

Schema description coverage is 100%, and each parameter already has a clear description, including examples for query. The description only restates the gutenberg_id restriction role and adds little semantic value beyond the schema. Baseline 3 applies.

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

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

States a specific verb and resource ('Search INSIDE the indexed corpus of top public-domain books') and the exact output ('matching passages, each with the book title, author, and a snippet'). It clearly distinguishes itself from siblings like book_search and book_get_text by emphasizing passage-level full-text search.

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

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

The description makes the use case explicit: find where a passage or phrase appears across books, with optional restriction to a single book via gutenberg_id. It does not name alternative sibling tools or state when not to use it, but the context is clear enough for an agent to select appropriately.

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