update_subscription_rate_plan_charge

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

No annotations are provided, so the description must fully convey behavior. It discloses the price conversion logic (dollars to cents) and references a similar pattern from 'create_invoice'. However, it does not mention side effects, reversibility, permissions, or what the response contains, leaving gaps in transparency.

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 a single dense paragraph that efficiently conveys the action, endpoint, required parameters, price conversion, and conditional logic. Every sentence serves a purpose, and the information is front-loaded with the core action and endpoint.

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?

Given the tool has no output schema, the description does not explain return values or success/failure indicators. However, it thoroughly covers all parameters, their constraints, and conditional relationships. For an update operation, this is nearly complete, missing only the response description.

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 input schema has 100% description coverage, but the description adds significant value beyond it: the price conversion rule, conditional requirement for billingPeriodAlignment, and the structure of chargeTier (currency and price required). This extra context greatly aids in correct parameter usage.

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 'Update a rate plan charge on a subscription' and provides the exact HTTP PUT endpoint. It distinguishes itself from sibling tools like 'add_subscription_rate_plan_charge' (add) and 'remove_subscription_rate_plan_charge' (remove), making the tool's purpose unambiguous.

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?

While the description does not explicitly state when to use this tool vs. alternatives, it provides clear context on required and conditional fields (e.g., billingPeriodAlignment required when chargeType is recurring). It implies usage for updating existing charges, but lacks explicit when-not or alternative guidance.

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