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

Although annotations already declare readOnlyHint=true and openWorldHint=true, the description adds substantial behavior: public sitemap/no key, newest-first limited recent coverage, headline/link-only payload, and exact x402 payment cost with failed calls not charged. This is valuable operational context beyond the annotations.

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?

The description is four short sentences with no filler. Scope, return contents, limitations, and payment are front-loaded and easy to scan.

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 two-parameter read-only news search with annotations and an output schema, the description supplies source, recency scope, content limitations, and payment details. Nothing critical for correct invocation or cost awareness 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?

Schema description coverage is 100%, and the schema already documents both parameters including the 200-character keyword limit and default article count. The description only restates the optional headline keyword filter and does not mention the limit parameter or its default, so it adds little beyond the schema.

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 the specific resource and operation: latest Reuters articles from Reuters' public news sitemap, with returned fields and newest-first ordering. It also explicitly limits scope to headlines and links with no article text, which distinguishes it from full-text extractor and other news-source siblings.

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?

Makes the use case clear: recent Reuters headlines, optional headline keyword filter, no key required. It also sets exclusions by saying only the most recent sitemap items are covered and only headlines/links are returned, but it does not name alternative tools for full text or historical search.

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