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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: a fixed 90-day window, per-engine granularity, and the specific analytical dimensions returned. It stops short of mentioning rate limits, auth, or result size/pagination.

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, front-loaded with what is returned before the alternative routing. Every clause carries information: the window, the breakdown, the fields, the sibling, the trigger. No filler.

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 no output schema, the description carries the return-value burden and does so by naming the four data dimensions. Combined with annotations covering the safety profile and a fully documented single parameter, an agent has everything needed to call this correctly.

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?

Only one parameter and schema coverage is 100%, so the schema already documents that fuzzy question text is accepted. The description reinforces 'single tracked question' and 'by name' but adds no syntax, matching rules, or format detail beyond what the schema states. Baseline 3 applies.

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 resource (per-engine history for one tracked question) with the concrete payload enumerated: presence rate, volatility, competitor substitution, daily trend. It also explicitly distinguishes itself from the sibling my_answers, so an agent can separate the two without opening either 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 both a positive trigger ('when the user asks about one specific question by name') and an explicit alternative ('For the answer text and the sources each engine cited, call my_answers'), which is the exact routing decision an agent faces among this large sibling set.

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