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 context beyond that: the content is 'public' (implying no auth) and the response contains 'metadata and body paragraphs' rather than, say, a summary or link. No further behavioral traits (rate limits, error behavior) are given, but with annotations and an output schema the bar is lower.

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 sentences, zero waste, and the core action is front-loaded ahead of the routing guidance. Every clause earns its place.

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 single-param read tool with an output schema and readOnly/openWorld annotations, the description covers purpose, input source, and sibling routing. Nothing an agent needs in order to select and call it correctly is missing.

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 with 100% schema description coverage, so the schema already documents the URL. The description's phrase 'canonical url' echoes the schema's own 'Canonical Rolling Stone article URL' without adding format, example, or constraint detail. Baseline 3 when the schema does the heavy lifting.

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'), a specific resource ('Rolling Stone article metadata and body paragraphs'), and the input it operates on ('canonical url'). An agent can distinguish it from rollingstone_headlines, rollingstone_sections, and rollingstone_news 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?

Explicitly routes the agent: use rollingstone_headlines for story lists, rollingstone_sections for topic browsing, rollingstone_news for the general feed. The alternatives and the conditions selecting them are named directly, 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.