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

Annotations already declare readOnlyHint, idempotentHint and closed-world, so the safety profile is covered. The description does add genuine behavioral context: 'Found does not mean the model read the page', 'robots (latest scan, information only)', and the weekly run spread, all of which shape how an agent should interpret results. It stops short of stating what happens when a site has no AI data or how large the payload can get.

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 entire description is one run-on sentence with deeply nested parentheticals (runSpread, competitorPages, searchFound, foundNotCited, robots), which makes it hard to scan or parse. The purpose is front-loaded, but the return-field catalog is delivered as an undifferentiated wall of text rather than structured clauses.

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, the description does attempt to cover the return payload, which is the right instinct, and it explains non-obvious fields like runSpread and the robots training signal. It omits error and empty-data behavior and never states which engines are available beyond the three named examples, leaving gaps for a fairly complex reporting tool.

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 both parameters are documented in the schema, including the 1-26 range and default of 4 weeks, so the schema does the heavy lifting. The description never mentions site_id or weeks and adds no meaning beyond the schema, which is the expected baseline of 3.

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 opening clause 'Show AI answer visibility per engine' gives a specific verb and resource, and no sibling tool covers AI answer visibility, so it is distinguishable. However, after the first clause the description stops describing purpose and becomes an inventory of return fields, which muddies what the tool fundamentally is.

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 statement of when to call this versus get_site_metrics, get_competitors, or get_report, and no prerequisites such as 'AI visibility must be enabled for the site'. The only usage-adjacent note is the qualifier 'where enabled', which hints at feature gating without explaining what to do when it is not enabled.

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