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

Beyond annotations (read-only, idempotent), the description adds valuable context: the availability limit (~435 titles), the default behavior of full_text, and the warning that full chapter notes can be very long. This helps the agent set expectations for output size.

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?

The description is two sentences, front-loaded with the main purpose and example queries, and contains no filler. Every clause contributes useful 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?

Given the output schema exists and annotations cover safety, the description is sufficiently complete. It mentions content composition, availability, and parameter behavior. Minor gap: no explicit handling for titles not in the ~435 set, but the output schema likely covers error responses.

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 coverage is 100% with descriptions for both parameters. The description adds further semantic guidance on when to set full_text=true ('only when the user explicitly wants the complete chapter notes') and warns about length, which enriches parameter understanding.

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?

The description clearly states the tool returns MRB's one-page summary of a book, including overview and chapter-by-chapter notes. It distinguishes itself from sibling tools (recommenders, lists, person recommendations, series order, search) by specifying the exact resource it provides.

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 gives explicit use cases: 'summarize Atomic Habits', 'what is Sapiens about?', or key ideas without reading. It does not explicitly mention when to avoid this tool, but the context strongly implies it is for summary requests, which is adequate.

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