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 covered. The description adds a genuinely new behavioral fact not present in structured data: the entitlement requirement ('Requires a plan with insight search'). It does not describe result shape or paging, keeping it short of 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?

Three tight sentences with no filler: purpose and examples first, then the usage trigger, then the prerequisite. Every sentence earns its place and the most decision-relevant information is front-loaded.

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-parameter, read-only search tool with a required query and a defaulted limit, this covers purpose, trigger and prerequisite. Since no output schema exists, the terse 'return the matching trends' leaves the response shape somewhat unspecified, which is the only real gap.

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 the baseline is 3; the example queries ('AI chips', 'sustainable packaging') add real meaning by showing that 'query' takes topical phrases rather than exact trend names. The limit parameter is left entirely to the schema, which is acceptable given full coverage.

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 (search) and resource (AI-generated trend insights), with concrete example queries that make the target content unambiguous. The clause 'rather than naming a trend' implicitly separates it from the get_trend/get_trend_ai_insights siblings, so an agent can route correctly without opening a 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?

Gives an explicit trigger condition ('when the user describes a topic or product rather than naming a trend') plus a hard prerequisite ('Requires a plan with insight search'). It stops short of naming the alternative tool (e.g. get_trend) for the naming-a-trend case, so the when-not path is implied rather than stated.

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