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

Annotations already establish that this is a safe, idempotent, non-destructive read, so the description rightly focuses elsewhere. It adds genuinely useful caveats beyond the annotations: links appear 'only where verified' and the content is editorial rather than live user reports, which sets expectations about freshness and trustworthiness.

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 sentences, front-loaded with what the dataset is, then progressively more specific about fields (about text, error_slug/url, category_fixes). Dense with parentheticals and slightly note-like, but every clause carries information and nothing is padding.

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 is not obliged to enumerate return fields, yet it helpfully names the key ones (error_slug, url, category_fixes) and explains their role. Combined with the zero-param schema and read-only annotations, this is complete enough for an agent to call and interpret the tool; only explicit when-to-use guidance 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?

The tool takes no parameters, so there is nothing for the description to disambiguate; baseline for a zero-param tool is 4. The description instead spends its words on result semantics, which is the right allocation for this tool.

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?

The description makes clear this surfaces a curated set of popular services that have status pages, plus their verified official status links, editorial blurb and error-guide links. The verb 'list' is implicit from the name, but the content and scope are unambiguous enough that an agent can distinguish it from check_website or list_errors.

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?

Usage is only implied: 'Editorial, not live user reports' hints that this is reference data rather than a live check, which nudges an agent away from using it for real-time status. However, no sibling tool is named and there is no explicit 'use this when…' condition, so the agent must infer the routing itself.

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