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

Annotations already cover read-only, idempotent, non-destructive, and closed-world behavior, so the description doesn't need to repeat safety. It adds genuine value by disclosing the shape of the response — industries, lagged knock-on effects, evidence counts by source type, and invalidation conditions — which is the main unknown for this tool given there is no output schema.

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?

One tight sentence that front-loads the core concept ('One trend') and then lists the payload components in a scannable sequence. No filler, no repetition of the title or annotations.

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 single-entity read with no output schema, the description does the heavy lifting by enumerating return fields. It stops short of covering not-found behavior or whether the trend's name/summary is included, but nothing essential for correct invocation is missing.

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?

With a single parameter at 100% schema description coverage, the schema already explains trend_id and even points to list_trends as its source. The description adds nothing about the parameter, which is acceptable at this coverage level but earns only the baseline.

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 names the resource ('One trend') and enumerates its payload — supported industries, knock-on effects with lag, evidence counts, and end conditions — which clearly separates it from list_trends. It never states the verb explicitly ('retrieve a single trend by id'), relying on the title and the leading 'One trend' to convey that, so it is clear but not fully self-contained.

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?

There is no when-to-use statement, no mention of list_trends as the discovery step, and no exclusion criteria. The only routing hint ('trend_id from list_trends') lives in the schema, not the description, so an agent gets no prose guidance on choosing this over siblings.

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