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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is fully covered. The description adds a meaningful behavioral nuance with 'as readers see them', hinting at visibility scoping, but says nothing about result ordering, pagination, or what an empty result means.

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, front-loaded with the scope statement followed by a concrete exemplar; nothing is wasted. It is arguably too terse for the number of near-duplicate search siblings, but the structure itself is clean.

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 three fully documented params, a complete annotation set, and no output schema, the description covers what is needed to call the tool correctly. It stops short of the disambiguation an agent needs in a toolset with search_items, search_lists, saved_items and my_library all present.

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%, so query, list and limit are already fully documented, including the 1-50 limit range and default of 20. The description reinforces the match scope (saved picks and list picks) but adds no format or syntax detail beyond the schema.

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 the person's Library') and narrows scope to saved picks plus picks inside their lists, which separates it from the broader search_items/search_lists siblings. It never names those siblings, 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?

The quoted example ('What was that ramen place from the Tokyo list?') conveys the intended use case well, implying personal-library recall rather than global catalog search. But there is no explicit when-to-use vs. search_items, my_library, or saved_items, and no stated exclusions.

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