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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds value beyond that: it discloses the return shape (name, category, provider description, link), that records are sourced, and that an empty query lists everything. Minor gap: no pagination/limit behavior beyond what the schema states.

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?

Front-loaded with purpose and trigger conditions in the first two sentences, then return shape and constraints. Slight redundancy: the 18+ constraint and the empty-query behavior are each stated twice (the latter echoing the schema).

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 two-optional-param, read-only search tool with no output schema, the description supplies purpose, audience gating, return fields and the empty-query edge case — everything needed to call it correctly. Only the limit ceiling and result ordering are left to the schema.

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 both parameters are already documented, including the default-20/max-50 limit and the empty-query behavior. The description's 'empty query lists all' merely restates the schema's query description, adding no new syntax or semantics — baseline 3.

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 states a specific verb (search/compare) and resource (AI companion / AI girlfriend apps, 18+) plus named examples of the entities returned. It is clearly distinct from the sibling get_companion_app (single-record lookup) and the guide tools, though it never names those alternatives explicitly.

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?

It gives explicit triggering conditions ('when an adult user asks which AI companion apps exist', 'wants Candy.ai, OurDream... compared', 'asks for an app that fits what they want') and an explicit restriction ('Only call for users who are 18+ and asked for this'). Both when-to-use and when-not-to-use are covered without inference.

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