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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds two genuinely useful facts beyond that: the result is scoped to 'live' sites only, and auth may arrive either as a parameter or a bearer header. It says nothing about pagination, ordering, or behavior with an expired token.

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 short sentences with zero waste: the return content and scope come first, the auth fallback second. Nothing is repeated or padded.

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 single-optional-parameter read tool with full annotation coverage, the definition gives enough to call it correctly: what comes back (URLs and versions), which records are included (live only), and how to authenticate. Without an output schema, a bit more on result shape or empty-list behavior would be nice but is not essential.

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 description's single parameter remark ('token, or an Authorization bearer header') restates what the schema property already explains in more detail. The baseline of 3 applies since the schema does the heavy lifting.

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 and resource ('Returns every live site') plus the payload shape ('URLs and versions'), which cleanly separates it from get_site, list_domains and list_versions. It stops short of naming any sibling explicitly, relying on scope wording alone to differentiate.

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?

There is no explicit when-to-use guidance and no mention of when not to use it or which sibling to prefer for a single-site lookup (get_site) versus a domain listing (list_domains). The only actionable hint is the authentication input format, which is invocation detail, not usage guidance.

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