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

Annotations are empty, so the description must disclose behavioral traits. It does list the possible return statuses (pending, approved, declined, failed, expired), which is useful. However, it does not state whether the operation is read-only, any side effects, error handling, or auth requirements. For a simple status check, this is adequate but not exhaustive.

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 sentence that front-loads the purpose, then immediately provides the output states. Zero waste and perfectly sized for the information content.

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 tool with one parameter, no output schema, and no annotations, the description covers the essential purpose and return values. It omits details like error conditions or response structure beyond status, but those are minor for a status-checking 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?

Schema coverage is 100% and the parameter description already explains the request_id as 'The `request_id` request-phones-tool returned.' The tool description adds no further parameter detail, so it meets the baseline without exceeding 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 specific verb 'Check' with the resource 'billing request' (a phone-count change) and explicitly ties it to request-phones-tool, distinguishing it from any generic status tool. The returned statuses are enumerated, leaving no ambiguity about what the tool does.

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 specifies the context (checking approval of a phone-count change filed by request-phones-tool) and names the source tool. It does not explicitly list alternatives or when not to use it, but the scope is clear enough that an agent can infer it is for this specific follow-up.

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