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

Annotations declare readOnlyHint and openWorldHint, so safety is covered. The description adds genuinely useful behavior beyond that: the story list is a 'single fixed batch' with 'no further pagination', which prevents an agent from hunting for page parameters, and it previews the profile fields returned.

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, front-loaded with the resource and its contents, followed by routing guidance. Dense but every clause carries information; the pagination note and sibling routing both earn their 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 read-only, two-parameter lookup with an output schema already present, the description covers the essentials: what is fetched, accepted inputs, and the pagination limit. Nothing critical is missing; only error behavior for invalid slugs is unaddressed.

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?

Schema description coverage is 100%, so the schema already documents both url and slug precisely. The description reiterates that either slug or a canonical author url is accepted but adds no syntax, format, or precedence detail beyond what the schema provides — the baseline 3 for fully-covered params.

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 precise verb (Fetch) and resource (Engadget author's public profile), and enumerates what it returns: expertise, social links, and latest story items. It also distinguishes itself from the closest siblings by name, so an agent can separate it from engadget_article and engadget_headlines without opening a 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 to alternatives: 'Use engadget_article for one story or engadget_headlines for section headlines.' This gives clear selection context. It stops short of stating exclusions for the author endpoint itself (e.g., what happens with an unknown slug), so it is not a full when/when-not treatment.

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