Billing Subscriptions Update

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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description does add genuinely useful non-annotation context: the required write_subscriptions scope and the API version. However, it says nothing about what a PATCH does when fields are omitted, whether the update is partial or a replace, or what happens on an invalid service_id.

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?

Four short lines, action statement front-loaded, with supporting metadata below. Nothing is padded, though 'API version: 2025-03' contributes little to an agent's decision to call the tool.

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?

Only two required parameters and no output schema, so the bar is low, but the core payload (subscription fields) is completely opaque in both schema and description. For a mutation whose argument is an untyped free-form object, pointing at an external 'Billing API reference' leaves a real gap an agent cannot resolve from the definition alone.

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 both parameters are already documented, and the endpoint line reinforces that service_id is a path parameter. The subscription parameter's schema is an unconstrained anyOf object/array, and the description does nothing to clarify its shape beyond deferring to 'the Billing API reference'. Baseline 3 is appropriate.

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?

States a specific verb (Update) and resource (the store's subscription for an app service), and pins the exact endpoint PATCH /concepts/app-cost/services/{service_id}/subscriptions. That clearly separates it from sibling reads like tiendanube_billing_subscriptions_get and from tiendanube_billing_plans_update or tiendanube_billing_charges_create, though it never says so explicitly.

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 choose this over the sibling tiendanube_billing_subscriptions_get or the plans/charges tools, and no stated preconditions beyond the scope string. The agent must infer the use case entirely from the name and endpoint.

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