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

Annotations already establish readOnly/openWorld/non-destructive, so the description's added value is the cost disclosure ('Billed $0.008 per request') and the per-call result cap ('up to 100 results'), which the agent cannot get from the schema. It does not cover error behavior or rate limits, keeping it below 5.

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 short sentences, each carrying distinct information (scope, return fields, filters/limits, price), with the highest-value facts front-loaded. No filler or redundant restatement of the title.

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 read-only search tool with no output schema, the description supplies the return field set (title, URL, snippet, author, source, publish date) and the billing model, which is what an agent needs to call and cost-justify it. Pagination beyond the 100-result cap and result-ordering are not addressed.

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 description coverage is 100%, so each parameter is already documented in the schema, including defaults and the enum for time_published. The description only restates the filter categories and the 100-result ceiling, adding no syntax or format detail beyond structured data.

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 verb and resource ('Search news articles') plus the scope ('from thousands of sources worldwide'), which separates it from social-media siblings like search_twitter and search_bluesky. It never names the nearest alternative (search_web) to sharpen the distinction, so it stops short of a 5.

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 filter dimensions (time period, source domain, country, language) imply the contexts in which the tool is useful, but there is no explicit when-to-use vs. when-not guidance and no named alternative such as search_web for non-news content. Usage must be inferred from the parameter list.

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