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

With empty annotations, the description carries the burden of behavioral disclosure. The verb 'Returns' implies a read-only operation, and the @return line indicates the output is in a 'values' object, providing some transparency. However, it does not explicitly state that no side effects occur, nor does it cover error behavior, missing customers, or any validation logic implied by the tool name.

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 concise lines with doc comments, front-loading the primary purpose. Every sentence provides value, with no redundancy or fluff.

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 tool is simple (one parameter, no nested objects) and an output schema exists, so a detailed description is not strictly required. However, the description leaves ambiguity about what 'validate' means versus the similar sibling tool, and does not mention error handling or edge cases like non-existent customer IDs, making it only minimally complete.

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 description explicitly documents the single parameter 'customer_id' as 'The customer's database id', which the input schema lacks. The @return description clarifies the output structure as a JSON object within a 'values' field, fully compensating for the 0% schema description coverage.

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 returns the current state of a customer's subscription, using a specific verb and resource. However, it does not differentiate from the sibling tool paywall__customer_subscription_status, and the 'validate' aspect of the name is not explained.

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 on when to use this tool versus alternatives such as customer_subscription_status. There are no conditions, exclusions, or prerequisite details to help the agent choose appropriately.

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