update_customer_metadata

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

The description adds that existing keys are left unchanged, which is a behavioral trait beyond annotations. However, the openWorldHint annotation (true) suggests potential side effects not explained. With annotations providing basic safety info, the description adds moderate value.

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 two sentences: first states the primary action, second clarifies the behavior for existing keys. Every word is necessary, and it is front-loaded with the core purpose.

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?

No output schema is provided. The description covers the main behavior for a simple metadata update, but could mention the return value (e.g., updated customer object) for completeness. Given low complexity, it 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?

The input schema has 100% coverage for parameter descriptions. The description adds context that updates are additive (existing keys unchanged), which provides semantic meaning beyond the schema. This justifies a score above baseline 3.

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 tool updates metadata key-value pairs on a Stripe customer. It specifies that existing keys not included are left unchanged, which differentiates it from potential overwrite behavior. This distinguishes it from sibling tools like 'update_subscription'.

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 is provided about when to use this tool versus alternatives, such as 'update_subscription' which might also update metadata. There is no mention of prerequisites or when not to use it.

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