Create a new entity, such as an actor, item, or enemy, in an RPG Maker MZ project. Provide the entity type and JSON data including a name to add it to your game's database.
Create a new entity. Provide the entity data as a JSON object. Required: name. Other fields use defaults if omitted.
| Name | Required | Description | Default |
|---|---|---|---|
| data | Yes | Entity data (JSON object). Must include "name". | |
| entityType | Yes | Entity type to create |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure for a mutation tool. It mentions that omitted fields default, which is useful, but omits critical traits such as permissions required, whether the operation is idempotent, what happens on duplicate names, and what the tool returns.
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?
Three short sentences, front-loaded with the core action, then required parameter info, then a default-behavior note. Every sentence contributes and nothing is wasted.
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 create tool with a nested free-form data object, an enum-driven entityType, no output schema, and no annotations, the description is minimally adequate. It states the required field and default behavior but leaves out return format, error behavior, and how entityType constrains the shape of data.
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 schema already documents both parameters thoroughly. The description adds a small amount of meaning by noting that only 'name' is required within data and that other fields default, but it does not explain the entityType-specific structure of the data object.
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 clearly states a specific verb and resource: 'Create a new entity.' However, it does not differentiate this tool from its many siblings like create_event, create_map, or create_project, so an agent must rely on the name alone to disambiguate.
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?
Usage is implied by the tool name and the instruction to provide entity data, but there is no explicit when-to-use guidance, no mention of when not to use it, and no reference to alternatives such as update_entity or get_entity.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.