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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds important behavioral context beyond annotations: the result set depends on whether a session token or Authorization header is supplied, yielding owned sites or public sample sites. It does not mention pagination or result ordering, but given the annotation coverage this is useful disclosure.

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 that front-loads the primary behavior and then states the conditional alternative. No redundant phrasing or unnecessary detail.

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 read-only listing tool with no required parameters and no output schema, the description gives the essential auth-dependent scope. It is nearly complete, though it could mention pagination or whether all sites are returned in one call.

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 baseline is 3. The description adds value by noting that `st` and Authorization/X-PQ-Session can also carry the session, and by explaining the effect of providing a session: listing your own pages rather than public sample sites.

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 states a specific verb (list) and resource (sites/pages), and clearly splits the two result sets: owned sites versus official public sample sites. It does not explicitly contrast itself with siblings like get_page or search_photos, but the listing purpose 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?

It explains the condition that selects the authenticated-owned mode versus the public showcase mode, which is useful. However, it does not state when to use this tool rather than alternatives such as get_page or check_slug, nor any exclusions or prerequisites beyond the token presence.

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