start_versionOpen a new version slot for an experience you already own. The live approved version keeps playing until the new one is reviewed.
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes | That game's manage key. | |
| game | Yes | The 12-character game id. | |
| releaseNotes | No | Public changelog notes, shown only after this build is approved. |
Changes observed during successful MCP inspections.
Input schema / properties / releaseNotesAdded value: +{
+ "additionalProperties": false,
+ "description": "Public changelog notes, shown only after this build is approved.",
+ "properties": {
+ "changes": {
+ "items": {
+ "maxLength": 240,
+ "minLength": 1,
+ "type": "string"
+ },
+ "maxItems": 12,
+ "minItems": 1,
+ "type": "array"
+ },
+ "title": {
+ "maxLength": 80,
+ "minLength": 1,
+ "type": "string"
+ }
+ },
+ "required": [
+ "title",
+ "changes"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare this is a non-read-only, non-destructive, non-idempotent operation. The description adds genuinely useful state semantics beyond that: the currently approved live version keeps playing until the new one is reviewed, which tells the agent this call does not disrupt production.
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?
Two short sentences with no waste. The action is front-loaded and the behavioral caveat follows immediately, so an agent can scan it in one pass.
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?
With no output schema, a fully documented 3-parameter schema, and annotations covering the safety profile, the description is nearly complete. Minor gap: it does not say what the call returns (e.g., a version identifier) or that upload_build is the expected next step.
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%, including the nested releaseNotes object with its own field constraints, so the schema carries the parameter burden. The description adds no meaning about game id, manage key, or when release notes should be supplied, so the baseline 3 applies.
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 and resource: 'Open a new version slot for an experience you already own.' The phrase 'an experience you already own' implicitly separates it from create_experience, but the distinction is never made explicit by naming the sibling.
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 prerequisite ('an experience you already own') is implied as a usage condition, but there is no explicit when-to-use guidance and no mention of the natural follow-up siblings such as upload_build or experience_status. Usage has to be inferred.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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