Retrieve custom property values from Blender objects or bones to access stored data for automation and scene inspection.
Read a custom property from an object or bone.
Args: object_name: Target object. bone_name: Target bone. armature_name: Armature containing the bone. property_name: Name of the custom property.
| Name | Required | Description | Default |
|---|---|---|---|
| bone_name | No | ||
| object_name | No | ||
| armature_name | No | ||
| property_name | No |
Changes observed during successful MCP inspections.
v3.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations present, the description carries the full burden of behavioral disclosure. It states that the tool reads data, which implies non-destructive behavior, but it does not explain what happens for missing properties, whether a return value is always provided, or any edge-case behavior. This is minimal for a tool with no annotation safety profile.
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 short and front-loads the core purpose in the first sentence, followed by a clean argument list. It wastes no words, though the brevity comes at the cost of deeper guidance.
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 tool with four parameters, no output schema, and no annotations, the description is incomplete. It does not describe the return value, behavior for missing properties, or how to choose between object and bone targets, leaving an agent to guess important calling details.
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 coverage is 0%, so the description must compensate, but it only restates the parameter names at a very shallow level ('Target object', 'Target bone'). It does not clarify relationships like when armature_name is required, how object_name and bone_name interact, or what property_name format is expected. The added meaning over the schema is minimal.
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 first line uses a clear verb and resource: 'Read a custom property from an object or bone.' It accurately describes the operation and distinguishes it from sibling set_custom_property, though it does not explicitly name that alternative.
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?
No guidance is given about when to choose this tool over alternatives such as set_custom_property, get_object_info, or similar property-related tools. The intended use is implied by the first sentence, but no exclusions, prerequisites, or comparison to siblings are provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.