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

Beyond the safety hints (readOnlyHint), the description provides deep behavioral traits, such as listing specific data points (daily and per-minute usage) and implementing a critical constraint ('Never returns the account e-mail').

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 highly efficient, using clear language to convey multiple complex pieces of information—functionality, safety, and best practices—in a compact format.

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 parameter-less introspection tool, the definition is maximally complete, addressing what the tool does, its constraints, and its intended use case.

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?

With zero input parameters, the description focuses entirely on defining the necessary context and the value delivered upon execution, thus fulfilling the role required of the tool definition.

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 defines the scope, detailing the reporting of account identity, plan, usage limits, and granted permissions, which sharply distinguishes it from search or data manipulation siblings.

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?

It provides explicit usage guidance by instructing the agent to 'Call it first to see what you are allowed to do,' establishing a clear operational prerequisite.

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