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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuine value by enumerating the returned fields (submitted/indexed counts, errors, warnings), but it says nothing about scope limits such as whether sitemap indexes and their children are both returned, or whether unsubmitted sitemaps appear.

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?

A single compact sentence with no filler, and the resource is front-loaded. The trade-off is that it is a noun phrase rather than a complete clause, which slightly weakens the opening.

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?

For a one-parameter read-only list tool with no output schema, the description supplies the return-field summary that would otherwise be missing, which is the main gap it needed to close. Only edge-case behavior (empty results, sitemap index hierarchy) is left unaddressed.

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 siteUrl description already specifies the exact format and references gsc_list_sites as the source of valid values. The description only adds the word "property", which is consistent but not additive, 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?

The description names the resource (sitemaps) and scopes it to Google and a single property, and it distinguishes itself from gsc_submit_sitemap/gsc_delete_sitemap by describing a retrieval of submitted sitemaps with counts and errors. It lacks an explicit verb ("list" only appears in the name), so the agent must infer that this is a read operation, keeping it short of a 5.

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: the mention of submitted and indexed counts, errors and warnings suggests it is the tool for auditing sitemap health. There is no explicit statement of when to prefer it over gsc_submit_sitemap, gsc_list_sites, or the bing/yandex equivalents, and no prerequisites or exclusions are given.

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