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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuine return behavior: results come 'best first' and each carries source id, text, and offsets that appear only 'when Google gives them', disclosing variability the annotations cannot. It stops short of rate limits or pagination details, so not a 5.

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 dense sentences plus the endpoint. The scope/result shape is front-loaded, then the sibling routing, with no filler; every clause carries 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?

For a read-only search with no output schema, the description supplies the essentials an agent needs: what is returned (source id, text, optional offsets), ordering (best first), scoping (notebook's sources), and the sibling alternative. Nothing critical is missing.

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%, so all four parameters (limit, query, sources, notebook) are documented in the schema and the description need not compensate. The description adds only the best-first ordering and result shape, not parameter syntax or defaults, so the 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 precise verb (Find) and resource (passages of a notebook's sources) and immediately distinguishes itself from the sibling notebook_ask by scope. An agent can tell it apart from notebook_ask and notebook_get_source without opening any schema.

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?

Explicitly says 'Raw passages only, no AI answer and no chat usage' and names the alternative and its selecting condition ('for an answer with citations use notebook_ask'). Nothing about when-to-use is left to inference.

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