create_subscription

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

No annotations are provided, so the description carries the full burden. It does not state whether creating a subscription requires specific permissions, whether it triggers immediate charges or webhooks, what happens on failures, or any side effects like recurring billing setup. The only behavioral hint is 'recorrente', which is already 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 a single, front-loaded sentence with no redundant or filler content. Every word earns its place, and the mention of Split is a precise additional detail.

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 9 parameters, 4 required, no output schema, and no annotations, the description is far too sparse. It fails to explain return values, error conditions, or how the subscription behaves after creation. For a complex, mutating tool in a payments context, this is a significant gap.

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%, with all 9 parameters clearly documented in the input schema. The description adds no parameter-level detail beyond what the schema provides (e.g., it doesn't explain the required fields or the nested Split configuration). The baseline 3 is appropriate when the schema does the heavy lifting.

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 states a specific verb and resource: creating a recurring subscription/monthly fee, with the added note about recurring Split support. It clearly distinguishes from siblings like create_payment (one-off) and cancel_subscription, though it doesn't explicitly name those alternatives. The parenthetical about Split is a useful scoping detail lacking in the schema's top-level description.

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?

There is no guidance on when to use this tool versus alternatives such as create_payment or simulate_payment, nor any prerequisites (e.g., customer must already exist). The description implies usage by naming the resource but does not articulate when it is appropriate or inappropriate.

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