Adds a new locale to an App Store version with localized description, keywords, what's new, and promotional text.
Add a new language (locale) to an App Store version — description, keywords, what's new, promotional text for that language. [POST /v1/appStoreVersionLocalizations]
| Name | Required | Description | Default |
|---|---|---|---|
| body | Yes | JSON:API request body (Apple schema: AppStoreVersionLocalizationCreateRequest). |
Changes observed during successful MCP inspections.
v2.8.0Input schema / properties / body / properties / data / properties / relationships / properties / placementsAdded value: +{
+ "additionalProperties": false,
+ "properties": {
+ "data": {
+ "items": {
+ "additionalProperties": false,
+ "properties": {
+ "id": {
+ "type": "string"
+ },
+ "type": {
+ "enum": [
+ "appAssetLibraryPlacements"
+ ],
+ "type": "string"
+ }
+ },
+ "required": [
+ "id",
+ "type"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "type": "object"
+}v1.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations already disclose that this is a non-read-only, non-idempotent, non-destructive operation. The description adds the HTTP endpoint and confirms creation semantics, but does not mention duplicate-locale behavior, permissions, or other side effects beyond what annotations provide.
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 front-loaded, compact, and contains no filler. It communicates the action, target resource, and relevant localized fields in one sentence.
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?
The schema is rich enough to show the required appStoreVersion relationship and nested attributes, but the description does not explain the create response, required parent version constraints, or duplicate-locale behavior. For a nested JSON:API mutation with no output schema, this leaves meaningful contextual gaps.
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 nested JSON:API body and its fields are already documented structurally. The description names several localized attributes and clarifies that they apply to the new language, but it does not add much beyond the schema.
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 gives a specific verb and resource: adding a new locale to an App Store version, with the localized metadata fields it carries. It is easy to distinguish from siblings like get, update, and delete localizations.
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?
The description implies usage by saying it is for adding a new language to an App Store version, but it does not explicitly state when to choose it over app_store_version_localizations__update or mention preconditions such as whether the locale already exists.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.