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

Annotations already declare readOnly, openWorld, idempotent and non-destructive. The description adds meaningful context beyond them: no wallet, no payment required, and no arguments — key facts for an agent deciding whether to invoke it in a paid pipeline.

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?

A single sentence front-loaded with [FREE] and the purpose, with zero filler. Every clause earns its place.

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 zero-argument preview whose entire purpose is to show response shape, the description is largely sufficient. It could hint at what the sample contains, but with no output schema and no parameters, little more is required.

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?

Zero parameters, so the baseline is 4. The description reinforces this with 'no arguments needed,' leaving no ambiguity about how to call it.

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 clearly it returns a sample response for news_search so the agent can preview the response shape — a distinct role next to the paid sibling news_search. The verb is implicit (it returns a static sample rather than performing a search), but the intent is unambiguous once you read it.

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?

Tells the agent exactly when to use it: before paying 0.009 USDC, implying the paid news_search is the alternative. It does not spell out the paid tool by name, but the condition that selects this tool is explicit and clear.

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