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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful context beyond them: articles are public/free to read (no auth friction) and it returns the full body paragraphs rather than just a summary.

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 tight sentences, zero waste. The core action and input are front-loaded, and the routing sentence follows. 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-parameter fetch tool with annotations covering the safety profile and an output schema handling return values, nothing essential is missing. Purpose, access model, and sibling routing are all present.

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, fully documented at 100% schema coverage ('Canonical Engadget article URL'). The description's mention of 'canonical url' merely echoes the schema, adding no syntax or format detail, so the baseline 3 applies.

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 (Engadget article metadata and full body paragraphs) plus the required input (canonical url). It is immediately distinguishable from the sibling feed/browse tools.

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 to engadget_headlines (find stories), engadget_sections (browse topics), and engadget_news (general feed), implying this tool is the right choice when a specific canonical URL is already in hand. It stops short of an explicit 'when not to use' statement, but the alternative mapping is clear.

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