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

Beyond the annotations (readOnly, idempotent, non-destructive), the description discloses that the operation is free, the authentication requirements, the anonymous fallback behavior, and the full set of returned quota fields. This significantly exceeds the annotation baseline.

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?

Two dense sentences plus a short tag convey the purpose, return fields, auth behavior, and anonymous tier case. No filler or repetition; information is front-loaded and every sentence adds value.

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 zero-parameter read-only utility with no output schema, the description covers everything an agent needs: what data is returned, the auth model, the anonymous behavior, and the safety profile. Nothing critical is missing.

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 has zero parameters, so there is nothing to document beyond the schema. The baseline of 4 applies; the description appropriately focuses on behavior and return data instead of parameter details.

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 uses a specific verb ('Returns') and a precise resource ('caller's current quota state'), enumerating the exact data fields returned. It is unambiguous and clearly distinct from any sibling tool, none of which appear to deal with quota state.

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?

The description provides clear usage context: it works with any valid X-Agent-Identity token and explains how keyless callers are treated. It doesn't explicitly name alternatives or state when not to use it, but no sibling tool offers this function, so the guidance is sufficient.

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