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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so the safety profile is covered. The description adds genuinely useful behavior — matching is embedding-based/semantic rather than keyword — but says nothing about result format, ranking, or what happens when the title doesn't match.

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?

Two short sentences with zero waste: the resource and scope come first, the mechanism second. Nothing could be cut without losing information.

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?

Adequate for a 3-parameter read tool with no output schema, but it omits what a result looks like (passages only, or with page/chapter locations) and the failure mode when no book matches the title — both relevant to calling it correctly.

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%, including the partial-match behavior of book_title and the limit default/max, so the schema carries the parameter burden. The description adds no syntax or format guidance beyond that baseline.

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+resource ('Semantic search within an uploaded book') and constrains scope to EPUB/PDF content, which implicitly separates it from library-wide siblings like search_library and search. It never names an alternative tool, so an agent must infer the boundary itself.

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?

Usage is implied by 'within an uploaded book' — use when you already know the book and want passages. But there is no explicit when/when-not, no mention of read_book_section as the alternative for reading a known section, and no prerequisite note that the book must already be uploaded.

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