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

Beyond the readOnlyHint annotation, the description adds significant behavioral context: it explicitly says the tool never returns full text, caps excerpts at 25 words, charges per 1,000 pages read, and makes failed pages free. These are non-obvious constraints an agent needs to know.

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 sentences with no redundant wording. The most decision-relevant facts are front-loaded: what is returned, the URL limit, the no-full-text guarantee, and pricing. Every sentence 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?

An output schema exists, so return value details are already covered. The description supplies the remaining operational context: URL count limits, excerpt length, pricing, failure handling, and the effect of the optional query. Nothing essential for invoking the tool correctly 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%, so the baseline is 3. The description largely restates the schema: urls are 'up to 10 news article URLs' and query is 'the excerpt is then the one about it.' It adds a small clarification that relevance measures 'how much the article covers it,' but does not substantially go 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?

The description opens with a precise verb and resource: 'Get the title, standfirst, date, source and a short verbatim excerpt...' and enumerates exact output fields. It does not explicitly differentiate from sibling tools like search_news or find_similar, but the URL-list input and 'Never returns the full text' make its scope clear.

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 gives no guidance on when to use this tool versus sibling tools such as check_coverage, find_similar, or search_news. The 'With a query' clause explains optional behavior but does not state when to prefer this tool or what alternatives exist.

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