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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds valuable context beyond annotations by specifying that API-key authentication is required and by enumerating the useful data returned (scopes, quota, expiry). No contradiction with annotations exists.

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 sentences carry real information with no wasted words. The purpose is front-loaded, the output fields are listed in one clause, and the usage rationale and authentication requirement are given in the second sentence.

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?

Given the tool's low complexity (no parameters, no output schema), the description is fully adequate. It tells the agent what the tool returns, why it should be used, and what authentication is required. An agent can invoke it correctly with no additional information.

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 and schema coverage is effectively complete, so there is nothing for the description to add about parameters. The baseline for a parameterless tool is 4, and the description appropriately focuses on behavior and output rather than inventing parameter guidance.

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 verb ('Report') and a clear resource: the API key making the call, and enumerates exactly what is reported (scopes, plan tier, expiry, remaining quota). This clearly distinguishes it from sibling tools like get_session or get_settings by focusing on API-key permissions and quota.

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 explicitly tells the agent when to use it: before attempting an operation, so it can check permissions rather than being refused. It does not name alternatives or exclusions, but no sibling tool appears to serve the same purpose, and the stated use case is specific enough.

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