List sites

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real value beyond that by disclosing the exact payload shape (five page-count buckets, indexing on/off, billable, IndexNow readiness), which matters since there is no output schema. It omits freshness/pagination but nothing 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?

One dense, front-loaded sentence that leads with scope and then lists the returned attributes. Every clause carries information, though the run-on parenthetical makes it slightly harder to scan than a bulleted field list.

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?

With no output schema and no parameters, the description's main job is explaining what comes back, and it does that thoroughly, including the semantic meaning of the billable flag. Minor gaps remain: page-count definitions and whether results are paginated or cached.

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 takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a 0-param tool applies. The description correctly implies the scope is all properties with no filtering options.

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?

Names the resource (every Search Console property connected to IndexMachine) and enumerates the returned fields, which implicitly separates it from list_pages and site_summary. It never states an explicit verb like 'returns' or 'lists' but the resource and scope are 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?

Usage is only implied: needing to see all connected properties. There is a useful forward reference — noting 'billable, which Request indexing needs' — that hints at the request_indexing sibling's prerequisite, but no explicit when-to-use, when-not-to-use, or named alternative such as site_summary.

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