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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that results are scoped to the caller's own account, which is useful context, but says nothing about rate-limit exhaustion behavior or what happens when no usage 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?

A single front-loaded sentence with no filler; the resource list (credits, usage, rate limit) is compact and informative. Nothing could be removed without losing meaning.

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?

With an output schema present and zero parameters, the description only needs to establish purpose and scope, which it does. The remaining gap – behavior at rate-limit boundaries – is minor for a read-only status tool.

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 takes zero parameters, which is the baseline-4 case; there is nothing for the description to disambiguate. The description correctly signals that no input is required by describing the call as purely a read of the caller's state.

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?

States a specific verb (Return) and a precise resource (caller's RAR.now API credits, usage, and rate limit), so an agent knows exactly what it retrieves. It doesn't explicitly contrast with siblings, but the domain is clearly distinct from the conversion tools, so confusion risk is low.

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?

Usage is implied by the resource itself – an agent would call it to check quota or rate-limit status. There is no explicit when-to-use guidance, no prerequisites, and no mention of alternatives, though the sibling set offers no competing option for this task.

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