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 the sections are public/editorial or RSS, a bit of useful context, but says nothing about caching, ordering, or coverage completeness.

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?

A single tight sentence with no filler, front-loaded with the resource and ending with the cross-reference to the consuming 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 lookup whose return values are covered by an output schema, the description gives enough to select and call it correctly. Only minor gaps around ordering/completeness of the section list remain.

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 schema carries no parameter semantics to compensate for; 4 is the baseline.

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 names the resource (NZ Herald public editorial or RSS sections) and ties it to the consumer tool, so an agent can tell it apart from nzherald_headlines/nzherald_article. It never uses an explicit verb like 'list', but the purpose is still unambiguous from context.

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?

'accepted by nzherald_headlines' effectively signals when to call this: to discover valid section values before querying headlines. No explicit when-not guidance is given, but the routing intent is clear.

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