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

Annotations already declare readOnlyHint=true and openWorldHint=false, covering the non-mutating nature. The description adds useful context beyond this by clarifying that the account is tied to the API key and that the tool reports balance and rate limits, which helps set agent expectations.

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 description is a single, front-loaded sentence that starts with the action verb 'Check' and immediately gives the resource and the relevant output fields. There is no filler or redundant phrasing.

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 has no parameters, no output schema, and read-only annotations, the description is sufficient for an agent to invoke it correctly. It names the account context and all reported values, leaving no major operational 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?

There are zero parameters and the input schema is empty, so there is no parameter-level semantics for the description to add. The baseline of 4 applies; the description correctly focuses on the tool's behavior instead.

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 states a specific verb and resource: 'Check the UndetectedGPT account linked to this API key'. It also lists the exact data returned—word balance, per-request word limit, and per-minute rate limit—making it easily distinguishable from the sibling humanize_text.

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 context for when to use this tool: when an agent needs account quota or rate-limit information. It does not explicitly name alternatives, but the sibling humanize_text is clearly different in purpose, so selection is unlikely to be ambiguous.

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