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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds behavioral context by disclosing that each series item carries a period timestamp and count and that series are organized per classification id. This supplements the annotations without contradicting them.

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 sentences deliver the resource, the series item structure, the use case, and the parameter choice guidance. It is efficiently organized with the core definition first and the usage guidance following. Slight redundancy with the schema's classification_type description costs it a full 5, but it remains compact and 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?

Given the read-only annotations, a comprehensive input schema, and the presence of an output schema, the description provides enough behavioral context for an agent to select and call the tool correctly. It covers what the output contains (period timestamp and count) and how to parameterize the classification dimension. One could ask for ordering or aggregation details, but the output schema and annotations reduce the burden on the description.

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%, with both time_filter and classification_type fully documented in the input schema, including enum definitions and the topic/intent distinction. The description repeats the classification_type meaning but does not add new parameter-level insight beyond the schema. A baseline of 3 is appropriate when the schema carries the semantic weight.

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 clearly states the tool returns a time series of trending classifications (topics or intents), one series per classification id. It distinguishes this tool from sibling analytics tools by specifying the classification dimension and the time-series shape. The verb 'get' plus the object 'trending classifications' makes the function's purpose unambiguous.

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 description says 'Use this to see how topical or intent demand shifts over time' and instructs to choose 'topic' for subject-matter trends and 'intent' for user-goal trends. This gives clear context for when this tool is appropriate and how to set the key parameter. It stops short of explicitly naming or excluding sibling tools, but the usage context is strong enough for an agent to differentiate it from static distribution or top-N tools.

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