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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered; the description adds real context beyond that – the empty-result behavior for non-metered workspaces, currency/USD conventions for costs, and the existence of a `howToRead` field carrying weighting and estimation caveats. It does not discuss caching or refresh cadence, so not a 5.

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 resource and billing-period scope, then two short qualifier sentences. The middle enumeration is a long run-on list, but with no output schema each returned field earns its place by telling the agent what to expect.

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 carries the return-value burden and does so thoroughly, covering allowance figures, overage pricing, BYOK estimates, usage breakdowns and reset timing. Only the contents of `howToRead` are left unexpanded, which is a minor gap.

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?

Zero parameters, so the baseline of 4 applies; nothing in the schema needs compensating for and the description correctly does not waste words on arguments.

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 names a specific resource and scope: the workspace's Managed-AI scan allowance for the current billing period, then enumerates exactly which figures are returned (tier, included, carried over, used/remaining, overage price, fair-use ceiling, BYOK cost, reset date). It is clearly distinct from siblings like get_scan_status or get_ai_visibility_metrics, though it never explicitly names an alternative to route against.

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 implied rather than stated: 'current billing period' signals a usage/billing query, and 'A workspace that is not on a metered Managed-AI tier returns no allowance figures' is a de facto condition, but the description never says when to call this versus get_scan_status or other scan-related siblings.

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