Creates a new auto-renewable subscription in App Store Connect by defining its group, reference name, product ID, and duration.
Create a new auto-renewable subscription
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | Reference name | |
| groupId | Yes | The subscription group ID | |
| productId | Yes | Product ID (e.g. com.app.monthly) | |
| subscriptionPeriod | Yes | Subscription duration |
Changes observed during successful MCP inspections.
v0.2.1Input schema / $schemaPrevious value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"Input schema / additionalPropertiesRemoved value: -falsev0.1.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true, openWorldHint=true, and idempotentHint=false, so the description should add what the annotations cannot: that this provisions a real product in App Store Connect, that it is non-idempotent (repeat calls create duplicates), and what state the new subscription starts in. It says none of this; 'create' is all the behavioral information provided.
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?
It is a single front-loaded sentence with zero waste, but the brevity here reads as under-specification rather than discipline — nothing is said that the name did not already imply.
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 destructive, open-world, non-idempotent creation tool with no output schema, the description omits what gets created, whether pricing/localization must follow, and how duplicates are handled. The rich parameter schema covers inputs, but the behavioral side is left entirely to annotations.
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 all four parameters (name, groupId, productId, subscriptionPeriod with its enum) are already documented in the schema. The description adds no semantics beyond that, which is the expected baseline when the schema does the work.
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 names a specific verb and resource ('Create a new auto-renewable subscription') and adds the qualifier 'auto-renewable', which mildly narrows scope beyond the tool name. However, it does nothing to separate this from close siblings such as create_iap, create_subscription_group, or create_subscription_offer, so an agent still has to infer the boundary itself.
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 versus create_iap, create_subscription_group, or create_subscription_offer, and no stated prerequisites even though a required groupId implies an existing subscription group. The agent gets a verb but no decision context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.