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

No annotations are present, so the description carries the behavioral burden. It conveys a read-only status operation but does not explicitly state that it is non-destructive, whether it consumes credits, or any rate-limit implications. The output schema covers return shape, but behavioral traits are otherwise minimal.

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 with no filler. Every word contributes to conveying what the tool does.

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 status tool with an output schema, this is nearly complete. It tells the agent what to expect and which key applies. Adding an explicit 'safe to call' note would make it fully complete, but the gap is small.

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 little to explain beyond the empty schema. Mentioning 'the key in use' clarifies that no explicit key parameter is required, which is a small but useful semantic addition.

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 clearly states the resource (the API key/account) and what it reports: credits left and monthly usage. It does not explicitly contrast with sibling tools, but the siblings are all crawl/detect/extract operations, so the domain distinction is clear.

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 intended use is implied: call this when you need to check remaining credits or usage for the active key. There is no explicit 'when to use this vs alternatives' guidance, though no sibling is a natural alternative.

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