create_subscription

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

With no annotations, the description bears full responsibility for disclosing behavior. It only states the action and target, without mentioning side effects, validation requirements, or any impacts on related entities. For a creation tool, crucial details like whether it requires an existing customer or generates payment schedules are absent.

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, concise sentence that is easy to parse and front-loads the key verb. However, it is almost too terse for a complex tool, offering little beyond a basic label, though it does not waste words.

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?

For a tool with 7 parameters and no output schema or annotations, the description is severely underspecified. It does not explain subscription semantics, interaction with payment tools, or expected behavior, making it insufficient for an agent to confidently invoke the tool in varied contexts.

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?

Schema description coverage is 100%, so the schema already documents all parameters. The description adds no parameter-level meaning, but per the baseline rule, a score of 3 is appropriate since the schema does the heavy lifting and the description does not mislead.

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 uses a specific verb ('Create') and resource ('recurring subscription'), clearly indicating the tool's primary action. It partially distinguishes from sibling tools like get_subscription and update_subscription, but does not elaborate on what constitutes a recurring subscription (e.g., automatic payments).

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 create_payment or create_pix_payment. The description lacks any context about prerequisites, typical scenarios, or exclusions, leaving the agent to guess based on tool names alone.

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