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

The readOnlyHint annotation indicates no side effects, and the description does not contradict that. No additional behavioral details, such as return shape or error behavior, are disclosed, but none are strictly required given the simple read-only nature.

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 short and includes useful sibling guidance, but the phrase 'stub subscription' and 'pay stub for' is awkward and reduces clarity. The wording could be tightened without adding length.

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?

The description conveys the tool's main purpose and mentions related tools, which is helpful given there is no output schema. However, it does not clarify what the returned subscription data would include or what 'stub' means in this context.

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 no parameters, so there is nothing for the description to clarify. Per the baseline for zero-parameter tools, this is adequate.

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 identifies the tool as retrieving subscription/billing line items for the business. It also distinguishes it from related profile and financial-summary tools, though the repeated use of 'stub' makes the wording somewhat confusing.

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 explicitly directs users to get_business_profile for profile data and get_financial_summary for trading financials, providing useful when-not-to-use guidance. It only implies when to use this tool, but the purpose statement makes that reasonably clear.

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