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

Annotations already establish readOnly/destructive/openWorld, so the bar is lower; the description still adds real behavioral context: it does not fetch the live page, it clarifies that 'On Google' means eligible rather than guaranteed to appear, and it notes the Cotlet API key must have access to the app. Return-shape specifics are covered by the enumerated fields.

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?

Front-loaded with the core purpose and the sibling exclusion before the field enumeration. It is relatively long, but each sentence (scope, exclusions, eligibility caveat, auth requirement) carries distinct information; the field list is the only mildly verbose part.

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, two-parameter tool with full schema coverage and no output schema, the description covers scope, the sibling exclusion, the eligibility semantics, and the auth prerequisite. Nothing essential to calling it correctly is missing, though it doesn't discuss rate limits or quota.

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% and both parameters are documented with format examples in the schema, so the baseline is 3. The description only marginally adds value by restating the 'URL must be inside the property' constraint already implied by the schema's 'inside the property' phrasing.

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?

States a specific verb and resource ('Index status of a URL') and enumerates exactly what is returned (status, crawl, canonical). It explicitly distinguishes itself from the live-fetch sibling: 'It does not fetch the live page; use test_live_url for that.' An agent can tell it apart from test_live_url and list_pages_by_index_status without opening a schema.

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?

Clearly routes the agent away from the wrong sibling ('use test_live_url' for the live page) and states the precondition that the URL must be inside the property. It does not contrast with list_pages_by_index_status for bulk status queries, so it stops short of full when/when-not coverage.

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