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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds what is retrieved (profile, biography, articles) but says nothing about pagination, rate limits, or the shape of 'recent items.' With annotations carrying the safety bar, a 3 fits.

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?

Two short sentences, front-loaded with the action and resource, then the disambiguation clause. No 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?

For a simple single-param lookup with an output schema already defining return structure and annotations covering safety, the description is essentially complete. Minor gap: it doesn't clarify how many 'recent article items' are returned, but that is a small omission.

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?

Only one parameter and schema description coverage is 100%, so the schema already documents `url`. The description reinforces that it must be a canonical HTTPS author URL, adding marginal format guidance, but the schema does the heavy lifting — baseline 3.

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?

Specific verb (Fetch) plus resource (Sky Sports author's public profile, biography, recent article items) and it names the sibling skysports_article as a distinct tool for a single story. An agent can separate this from skysports_article without opening either 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 skysports_article for one story,' which clarifies when to pick the alternative. It gives no other prerequisites or exclusions, but the core when-vs-alternative guidance is present and clear.

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