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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so safety is covered. The description adds real context beyond them: match fields (titles, questions, balance lines, card headlines) and the exact result shape including a 20-item cap. It does not say what happens when more than 20 shelves match or whether results are ranked, which keeps it at 4.

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 sentences: the action first, then match fields and return shape. Nothing is repeated from the title or annotations and no sentence is padding.

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 single-parameter read-only search with no output schema, the description supplies the match surface and the returned summary fields, which is what an agent needs to interpret results. The only gaps are ordering and behavior past the 20-result cap.

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% and already states every word must appear, so the schema carries the syntax burden. The description nonetheless adds meaning by enumerating the searchable fields, telling the agent what kinds of tokens actually match.

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 shelves by keyword") plus the fields matched and the result count/fields, which clearly separates it from list_shelves and get_shelf in spirit. It never names a sibling or explicitly contrasts scope, so it stops short of a 5.

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 only implied: having keywords means you search. There is no statement of when to prefer this over list_shelves (browse all) or get_shelf (single shelf detail), and no exclusion conditions.

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