update_subscription

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

Annotations already indicate mutation (readOnlyHint=false), non-destructive (destructiveHint=false), and idempotent (idempotentHint=true). The description adds that cancellation happens at period end (not immediate), but does not disclose other behaviors like side effects, permission requirements, or error states.

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?

Single sentence that efficiently conveys the tool's purpose and key capabilities. No extraneous words or repetition of schema details.

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?

Covers the two main use cases without output schema. However, it omits details about response format, error handling, or that the tool is idempotent. Given low complexity and existing annotations, the description is mostly sufficient.

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?

Input schema provides 100% coverage with descriptions. The description adds contextual meaning: 'cancel_at_period_end' is clarified as 'at the end of the current period' and 'price_id' as 'switch to'. This goes beyond the schema's basic descriptions.

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 it updates a Stripe subscription and specifies two concrete actions: schedule cancellation at period end or change price. This effectively distinguishes it from read-only tools like get_subscription or list_subscriptions.

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?

No guidance on when to use this tool versus alternatives such as create_invoice or finalize_invoice. Does not mention prerequisites or scenarios where update_subscription is appropriate.

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