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

The annotations already declare readOnlyHint=true and openWorldHint=true, so the safety and external-fetch profile is covered. The description adds useful framing ('public feed', 'returns headline items') but doesn't disclose pagination, result caps, or freshness/rate-limit behavior. With annotations carrying the behavioral burden, a 3 is appropriate.

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, each doing routing work: scope, the section-specific alternative, the discovery tool, and the article tool. Front-loaded with the primary purpose and free of 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 zero-parameter, read-only headline fetch with an output schema present, the description covers purpose, scope, and the full decision tree of sibling tools. An agent has everything needed to call it correctly and route elsewhere when appropriate.

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?

Parameter count is 0, so the baseline is 4. The description correctly frames this as taking no arguments, and schema coverage is 100%. There is nothing further for it to add.

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 action ('Fetch 7NEWS Australia top stories'), names the resource ('the general top-story stream'), and explicitly distinguishes itself from sibling sevennewsau_headlines by contrasting the general stream with section-specific lists. An agent can select this tool over alternatives 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?

It names three alternatives (sevennewsau_headlines, sevennewsau_sections, sevennewsau_article) and the exact condition that selects each: section slug discovery, section-specific lists, and fetching one story's body. Nothing is left to inference.

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