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

Annotations already declare readOnly, idempotent, open-world and non-destructive behavior, so the safety profile is covered. The description adds a useful pricing detail ('cost: 1 credit') that the annotations do not carry, but it omits what happens on missing titles, redirects or disambiguation pages.

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 front-loaded sentence plus a parenthetical cost note; every element carries information and nothing is padded. It is slightly list-like rather than framed as an action, but no wording is wasted.

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?

With 2 parameters, no nested objects and no output schema, the description does well to enumerate the returned fields, which compensates for the missing output schema. It still leaves gaps around failure modes and language handling for a tool that operates over an open-world corpus.

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 both parameters (lang with default en, required title) are already documented structurally. The description adds nothing beyond that, such as whether title accepts URL slugs versus exact article names, so the baseline of 3 applies.

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 a concrete resource (a Wikipedia article) and enumerates exactly what is returned: lead summary, description, coordinates and Wikidata id. It is clear what the tool fetches, though it does not explicitly differentiate itself from the sibling wikidata_lookup, which offers overlapping identifier data.

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 guidance and no mention of alternatives. An agent gets no signal about when to prefer this over wikidata_lookup, read_url, govuk_page or general web search tools in the sibling list, nor about behavior when an article does not exist.

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