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

The readOnlyHint annotation already signals no state mutation, and the description adds 'optional lastmod' which is schema content. It does not disclose return format (e.g., XML string vs. file) or any limits, but the safe/non-destructive behavior is covered by annotations.

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?

The description is a single sentence that is front-loaded with the core purpose and includes the key parameter context. Every word earns its place with no redundancy.

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?

The tool is simple (2 params, no nested objects) and no output schema exists. The description implies the output (XML), but does not explicitly state whether it returns the sitemap content directly or writes it somewhere. For a low-complexity generator, this is nearly complete.

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 0%, so the description must compensate. It does convey that 'urls' is a list of URLs and 'lastmod' is an optional date, adding basic meaning beyond the raw schema types. However, it lacks detail on URL format (absolute vs relative) or date format (ISO 8601).

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 clearly states a specific verb and resource: 'Build an XML sitemap' from a list of URLs. It distinguishes the tool from sibling generators like robots-txt-generator or schema-generator by naming the exact output type (XML sitemap).

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?

The description implies usage context (when you have a list of URLs and need a sitemap), but it does not explicitly state when not to use it or mention alternatives. It is clear enough for a simple tool, but lacks explicit exclusions or comparisons.

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