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

The description adds specific behavioral details beyond annotations: what data is returned (extract, thumbnail, artist credit, top-10 list) and discloses licensing (CC BY-SA 4.0). These enrich the agent's understanding of output structure and provenance without contradicting the readOnly or idempotent hints.

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 two sentences, front-loaded with the verb and resource, then enumerates content details, and finishes with constraints and licensing. Every clause adds value with no redundancy or filler.

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?

Even with an output schema present, the description explicitly states the key data components, language limitation, auth requirement, and license. For a read-only, single-parameter fetch, this is fully sufficient for an agent to invoke it correctly without additional context.

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?

The input schema already fully documents the 'date' parameter with format, default, and description (100% schema coverage). The description only mentions 'any date,' which adds no new semantic information beyond what the schema provides, so a baseline score is appropriate.

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 states a specific verb ('Fetch'), a clear resource ('Wikipedia's daily curated highlights'), and explicitly enumerates the return components (Today's Featured Article with extract and thumbnail, Featured Image of the Day with artist credit, top 10 most-read articles). This distinguishes it from sibling Wikipedia tools like article summaries or on-this-day feeds.

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 provides clear context: 'English only' and 'No auth required' inform when and how to use the tool without needing extra setup. It does not explicitly name alternative tools or state when not to use this one, but the context is sufficient for basic routing.

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