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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds genuine behavioral context beyond them: the supported artifact type and the failure modes (subscriber-only and bot-challenged responses). It stops short of noting pagination or content-length limits, costing the top score.

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 tightly written sentences, front-loaded with the action, then limitations, then routing to siblings. 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, return values need no description. The description supplies everything required to select and invoke correctly: what it fetches, what it refuses, and which sibling handles each alternative case.

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 coverage is 100% and the single parameter is already documented as 'Canonical Reuters article URL'. The description reinforces the canonical-url requirement but adds no syntax or format detail beyond the schema, 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?

Specific verb 'Fetch' plus resource 'Reuters article's public metadata and body paragraphs' from a canonical url. It also distinguishes the artifact type ('normal' article) by excluding live blogs, video and podcast pages, so an agent can tell it apart from reuters_news and reuters_section immediately.

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?

Explicit when-to-use (single article fetch by url), when-not (live blogs, video/podcast pages, subscriber-only stories, bot-challenged responses), and named alternatives (reuters_articles, reuters_news, reuters_section) with their respective roles.

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