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

With no annotations provided, the description carries the full burden. It transparently indicates a read-only operation ('Retrieves') and specifies the exact data returned (requests used and remaining), giving the agent confidence about its side-effect-free nature. It does not disclose auth requirements or error behavior, but for a simple retrieval this is adequate.

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 composed of two sentences, each adding value. The first states the core function and output, and the second provides a practical usage hint. It is front-loaded, concise, and free of filler.

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 simplicity (no parameters, no output schema), the description fully covers the essential information: what it does, what it returns, and when to use it. There are no missing details that would hinder an agent's ability to select and invoke the tool correctly.

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 the schema is empty with 100% coverage. Since there are no parameters to describe, the description doesn't need to add anything. The baseline for zero parameters is 4, and the description does not detract from it.

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 tool's function using a specific verb ('Retrieves') and a specific resource ('the current user's API rate limits'), including the data it returns (requests used and remaining). This clearly distinguishes it from sibling tools like get_music and get_sfx, which deal with content retrieval.

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 offers explicit context for when to use the tool: 'Use this to monitor your quota.' While it does not mention when not to use it or explicitly compare with alternatives, the sibling tools are clearly in different domains, so the guidance is sufficient for a straightforward use case.

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