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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. Beyond that, the description discloses that billing, assignment and live activation are separate stages, and that unknown checkout or provider outcomes leave the original request and number intact — real behavioral context an agent cannot get from the annotations.

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?

Three short sentences, front-loaded with the core action, then the multi-stage semantics and the retry guidance. The phrasing is slightly telegraphic ('Billing, assignment and live activation are distinct.'), but nothing is wasted.

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?

There is no output schema, so the description should convey what a status result looks like. It hints at stage separation but never enumerates possible states or explains how a caller distinguishes pending checkout from a live activation — leaving a meaningful gap for a status-read 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 description coverage is 0% for both required parameters, so the description carries the full burden. It implies ownership scoping through 'owner-authorized' but says nothing about what business_id or request_id must contain, where request_id comes from, or the format expected.

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 gives a specific verb and resource: 'Read an owner-authorized extra-number request.' That is clearly distinguishable from request_extra_number (a mutation) and from narrow status readers like get_checkout_status. It stops short of explicitly naming which sibling handles billing-only or activation-only polling, so it is clear but not fully differentiated.

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 implies the tool is used to poll the state of an existing extra-number request, and it adds a negative guideline: no replacement purchase is needed when an outcome is unknown. However, it never says when to prefer this over get_activation_status or get_checkout_status, nor what prerequisite state (an existing request_id) is required.

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