Lists loaded material libraries with material and appearance counts to help choose the right library for further material queries.
Loaded material libraries (physical materials and appearances).
Returns {"libraries": [{"id", "name", "is_native", "material_count", "appearance_count"}]}.
Example: material_list_libraries() -> pick a library for material_list(library=...).
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden of behavioral disclosure. It clearly indicates a read-only listing behavior by saying 'Loaded material libraries' and by documenting the returned structure, including counts; no mutation or side effects are implied. It does not explicitly say permissions are unnecessary, but the read/listing nature is clear.
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 compact and front-loaded: purpose first, return shape second, usage example third. Every sentence adds useful information without redundancy.
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 zero-parameter listing tool without an output schema, the description provides the return object structure and a concrete usage example. An agent has enough information to call it and use the result correctly.
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?
The tool has zero parameters, so parameter semantics have a baseline of 4. The example correctly shows no arguments and points to the related material_list(library=...) parameter usage.
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-resource pair ('Loaded material libraries') and explicitly scopes the resource to physical materials and appearances. It also names the returned fields, so the agent can distinguish it from sibling tools like material_list, material_get, and appearance_list.
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 example establishes a clear usage pattern: call material_list_libraries() first, then pass a selected library into material_list(library=...). It does not state explicit exclusions or alternatives beyond that, but the context is sufficient for correct selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.