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 useful behavioral scope by clarifying it reads from the 'public feed' and returns 'headline items from the general top-story stream', distinguishing it from the section-filtered sibling. It does not mention pagination, result counts, or refresh cadence, which keeps it below a 5.

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 short sentences, each earning its place: the first states what it does, the second routes to the section sibling, the third points at slug discovery. The core purpose is front-loaded and there is 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?

With an output schema present, the description needn't explain return values, and annotations cover safety. For a zero-parameter feed-reader, the definition gives complete routing context (this tool plus two named alternatives) with nothing an agent needs to call it correctly left out.

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 there is no parameter meaning for the description to add; the baseline for a param-less tool is 4. Nothing is missing or misleading in how inputs are framed.

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 (Fetch) and resource (Rolling Stone top stories from the public feed), and immediately scopes the content to 'headline items from the general top-story stream'. It explicitly distinguishes itself from rollingstone_headlines (section-specific) and rollingstone_sections (slug discovery), so an agent can route correctly 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?

Provides explicit when-to-use and when-to-use-something-else guidance: use this for the general top-story stream, use rollingstone_headlines for a section-specific list, and rollingstone_sections to discover slugs. Both the alternative and the condition that selects it are named, 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.