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 that this reads from a 'public feed' and returns 'headline items,' which usefully clarifies scope beyond the annotations, though it does not mention pagination or freshness limits.

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?

Four sentences, all front-loaded and purposeful. The first sentence delivers the core purpose, and each following sentence earns its place by routing to a specific sibling tool.

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 feed tool with an output schema and safety annotations, the description is complete. It covers purpose, scope, and routing without needing to explain return values that the output schema already defines.

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 tool takes zero parameters, so the baseline is 4. There are no parameter semantics to clarify, and the description correctly avoids describing non-existent inputs.

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: 'Fetch News.com.au top stories from the public feed.' It distinguishes itself from siblings by explicitly scoping to the 'general top-story stream' and contrasting with section-specific lists from newscomau_headlines.

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 newscomau_headlines for a section-specific list, newscomau_sections to discover slugs, and newscomau_article for a single story body. It covers when to use this tool versus three named alternatives, leaving nothing to inference.

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