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

Annotations already declare readOnly/idempotent/destructive=false, so the bar is lower. The description still adds real value: the caveat that 'URL counts are listed URLs, not indexed URLs' prevents misinterpretation, and it explicitly scopes out write operations (cannot submit, resubmit or delete).

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?

Front-loads the usage trigger before the descriptive detail, and each sentence carries a distinct purpose (trigger, output shape, sitemap_index, caveat, read-only scope). Slightly dense but nothing wasted.

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 enumerating return fields is partially redundant, but the usage trigger, index-recursion behavior, listed-vs-indexed caveat and read-only scope make the definition fully actionable for an agent.

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 baseline is 3. The description restates the sitemap_index behavior ('list the sitemaps inside a sitemap index') but adds no format or edge-case detail beyond what the schema already documents.

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 and resource ('Lists the sitemaps submitted for one property') and enumerates the returned fields, making it clearly distinct from siblings like list_properties and get_performance.

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?

Opens with an explicit trigger condition ('Use this when the user asks which sitemaps a site has... whether Google read them, or whether they have errors'), plus a second usage case for sitemap_index. It never names an alternative or a when-not condition, so it falls short of a 5.

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