Creates a new in-app purchase for an app by defining its product ID, type, and reference name through App Store Connect.
Create a new in-app purchase
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | Reference name for the IAP | |
| appId | Yes | The App Store Connect app ID | |
| productId | Yes | Product ID (e.g. com.app.gems_pack) | |
| inAppPurchaseType | Yes | Type of in-app purchase |
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, idempotentHint=false, and openWorldHint=true, so the safety profile is known. The description adds nothing beyond that: it doesn't mention that retries could duplicate IAPs (non-idempotent), that this modifies a live app's catalog, or what the resulting state is. With annotations present, the bar is lower, but zero added context still only merits a 2.
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?
A single front-loaded sentence with no filler. It is efficient, though its brevity is partly a symptom of under-specification rather than deliberate concision.
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 four-required-parameter mutation tool with no output schema, the schema and annotations together carry most of the load. However, the description omits the natural follow-on steps (set_iap_price, submit_iap_for_review) and the fact that creation is irreversible/destructive, leaving the agent with only minimum viable context.
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 each of the four required parameters documented, including the inAppPurchaseType enum values. The description adds no parameter meaning (e.g. productId format conventions or immutability), so the baseline 3 is correct.
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 (create a new in-app purchase), which is unambiguous and clearly distinct from update_iap, delete_iap, and list_iaps by name. It stops short of differentiating at the behavioral level (e.g. what a new IAP is initialized with), so it earns a 4 rather than a 5.
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 siblings like create_subscription or create_custom_product_page, and no prerequisites (the parent app must exist, productId must be unique). The agent is left to infer usage entirely from the name.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.