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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered; the description adds substantial context beyond that – weighted check accounting, BYOK scans excluded from the allowance, ESTIMATE caveats with null handling, and the non-metered-tier behavior that returns no figures rather than zeros. It does not cover auth requirements or freshness/rate-limit behavior beyond pricesLastChecked.

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?

Purpose is front-loaded, and every clause carries information, but the entire body is a single run-on sentence packed with nested parentheticals that is hard to parse. Detail is appropriate given no output schema, yet the structure is not disciplined.

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 carries the full burden of explaining returns and does so exhaustively – allowance numbers, BYOK estimate fields, checksBySurface, assistantMessages.bySurface, reset timing, and the non-metered edge case. It is complete for the tool's shape, though the density makes it harder to use than a structured enumeration would be.

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 the baseline is 4. The description explains scoping implicitly (current billing period, current workspace) rather than through inputs, and there is nothing in the schema left to clarify.

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?

Opens with a specific verb+resource+scope: "The workspace's Managed-AI scan allowance for the current billing period." An agent can immediately distinguish this billing/quota tool from the metric-oriented siblings (get_ai_visibility_metrics, get_insights), and the follow-on enumeration of what the payload contains reinforces the unique purpose.

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?

Provides an explicit workflow trigger: "Check it before suggesting more prompts, engines or passes per prompt," plus the fallback condition for non-metered tiers. It does not name an alternative sibling or state when NOT to call it, so it stops short of a 5.

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