mat_set_diffuse

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the tool as destructive and not read-only, so the description doesn't need to restate that. It adds useful context by disclosing which internal property is written for each material type and the accepted color formats, but it does not address error behavior, unsupported material types, or whether the material must already exist.

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 brief and front-loaded with the primary action, followed by the adaptive behavior and color format. The bilingual repetition doubles content but is acceptable for localization; overall it is compact and well-structured with no filler.

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 simple two-parameter setter with full schema coverage and annotations, the description covers the core behavior well. It is slightly incomplete in not explicitly limiting support to Standard/Physical materials or describing error handling, but these are minor omissions for this tool.

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 baseline is 3. The description repeats the color format information already present in the schema ('[r,g,b] (0-255) or #RRGGBB') and adds nothing additional about the material parameter, providing no extra semantic value 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 states a specific action ('Set the diffuse/base colour'), identifies the resource (material), and explains the adaptive behavior for StandardMaterial vs PhysicalMaterial. This clearly distinguishes it from sibling tools like mat_set_specular or mat_set_property by pinpointing the exact property being set.

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 through the clear purpose and the note about auto-adapting to Standard/Physical materials, but the description does not explicitly name alternatives or state when not to use this tool. It leaves the agent to infer that other mat_* tools are for different properties, offering no explicit when/when-not guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.