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 genuinely useful behavior beyond that: the index is a fixed `/sitemap.xml`, output is a directory of child sitemaps with inferred types, and the tool accepts no input. It stops short of describing pagination or error behavior, but the output schema covers the return shape.

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 sentences, zero padding. The scope and source are front-loaded, followed immediately by the routing instruction to the sibling tool.

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 return format need not be explained, and annotations carry the safety profile. For a zero-parameter fixed-endpoint lister, the description supplies everything needed to call it correctly and to pick the right sibling.

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 schema has zero parameters and 100% (vacuous) coverage, so the baseline is 4. The description reinforces this by stating no storefront URL input is accepted, which helps the agent avoid trying to pass one.

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 (List) and resource (child sitemap directory and inferred sitemap types) with the exact source (`/sitemap.xml` index). It explicitly contrasts with the sibling rebag_sitemap_urls, so an agent can distinguish the two index-vs-URL tools without opening either 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 the alternative tool (rebag_sitemap_urls) and the condition that selects it (listing URLs within a child sitemap), and adds an explicit exclusion: no storefront URL input is accepted. When-to-use, when-to-switch, and an input constraint are all stated.

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