featured_article

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

With no annotations and no output schema, the description carries the full burden and does disclose the returned payload ('full long-form extract plus thumbnail') and the qualitative nature of the content, which the structured fields do not. It stops short of describing error or edge behavior (e.g., what happens for a language with no featured article that day) or any rate/caching behavior, so it is helpful but not exhaustive.

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?

Front-loaded with the core action and resource, then the return value, then the sibling routing — a sensible order. The middle sentence ('reliably high-quality, surprising, in-depth content') is somewhat promotional and expendable, but the piece as a whole is tight and well under the point of bloat.

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-required-param, no-output-schema tool, the description supplies the retrieval semantics, the returned content shape, and the sibling alternatives an agent needs. The only remaining gap is edge-case behavior such as missing featured articles per language, which is minor given the tool's simplicity.

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% for the single `lang` parameter, including its enum and default, so the baseline is 3. The description adds no language-specific meaning beyond what the schema already documents.

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 ('Get today's Wikipedia Featured Article') and immediately defines the resource as the single article Wikipedia editors showcase that day, so the agent knows exactly what is being retrieved. It also names the two nearest siblings it must not be confused with, making it unambiguous without opening any schema.

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?

Explicitly routes the agent: use picture_of_the_day for the daily image and on_this_day for historical events, with a stated rationale ('a strong daily source of hooks and deep dives') for when this tool is the right pick. Both the when-to-use and when-to-use-something-else conditions are given.

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