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

The description explains what the response contains: a description of the site plus links to sitemap, docs, contact, and discovery documents. Since annotations already declare readOnlyHint, idempotentHint, and openWorldHint, the description adds useful content-level context rather than repeating annotation data. No behavior contradicts the 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 concise sentence and avoids unnecessary words. It is slightly awkward as a noun phrase ('What Sunset is') and the phrase 'every discovery document' is a bit vague, but overall it is appropriately short.

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 zero-parameter informational tool, the description covers the main return content and scope. There is no output schema, but the description names the key resources included in the response. It would be slightly stronger with an explicit statement that this is the recommended first call for understanding the site.

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 tool has zero parameters and full schema coverage, so there is nothing for the description to add about parameter semantics. The baseline of 4 applies because the schema already fully captures the parameter surface.

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 identifies what the tool does: it returns an overview of Sunset with links to key resources. It is distinguishable from the sibling tools because it is the only one that provides site-level orientation rather than product, checkout, or page operations. It lacks an explicit verb like 'retrieves' or 'returns,' but the meaning is unambiguous.

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 gives no guidance about when to call this tool versus alternatives like read_page or search_pages. It implies general informational use but does not explicitly state that it should be used for initial site discovery or that it supersedes other tools for specific lookups.

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