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 structurally. The description adds only the 'capped' notion, which the schema already conveys via limit's default 50 / max 250; it doesn't disclose pagination, rate limiting, or what happens when a section is empty or missing.

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 with no filler. The core purpose is front-loaded, and the routing guidance follows immediately, so 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?

An output schema exists, so return values need not be explained, and annotations cover the safety profile; the description supplies purpose and sibling routing. It is nearly complete, with only minor omissions around pagination/empty-section behavior for a capped-listing tool.

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 both parameters (type enum values and limit bounds) are already fully documented in the schema. The description's 'matching its type' alludes to the type filter but adds no syntax or defaulting detail beyond what the schema provides, so the baseline of 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 precise verb ('Fetch') plus resource ('capped URL records from a SKIMS child sitemap matching its type'), and explicitly distinguishes itself from the index tool (skims_sitemaps) and the static-page tool (skims_pages). An agent can tell it apart from those siblings 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?

Names two concrete alternatives and their distinct purposes: skims_sitemaps to discover the index and skims_pages for static pages. It clearly implies this tool is for pulling URL records once the child sitemap is known, though it doesn't state the pre-condition (obtain a child sitemap from the index) as an explicit rule.

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