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

With no annotations supplied the description carries the full burden; it does disclose the cost model (free), the failure mode (named refusal on malformed queries) and one hard block ('radar-api-data leg form is refused as BARRED'). It omits auth/permission requirements, whether the call has any side effects, and whether refusals are distinguishable machine-readably.

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 the 'FREE' qualifier and the returned column list in a compact parenthetical. Little waste, though the second sentence packs two distinct refusal rules together without structure.

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?

There is no output schema, and the description compensates by naming the five returned fields, which is genuinely helpful. But with zero parameter documentation and no annotations, the definition still leaves an agent unsure how to construct a valid query or how this relates to the other three trending_digest tools.

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 0% and neither parameter is described in the schema, so the description must compensate. It hints at a 'query' concept and at one barred leg form, but never explains the difference between 'leg' (string) and 'legs' (array), accepted syntax, or whether they are mutually exclusive.

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?

Specific verbs and resource: 'validate a digest query and read the leg table', with the returned columns enumerated. The purpose is legible, but nothing distinguishes it from the closely-named siblings trending_digest_criteria, trending_digest_get and trending_digest_sample.

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 the call is FREE and that malformed queries are refused at no cost, which is a soft incentive to use it, but it never states when to pick this over the sibling digest tools. No prerequisites, no ordering guidance (e.g. validate here before calling trending_digest_get).

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