rhino_set_material

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

Annotations already signal a mutation (readOnlyHint=false) and idempotency (idempotentHint=true). The description adds no additional behavioral context: it doesn't mention whether the material must already exist, whether it overwrites previous assignments, or how failures are handled. With annotations present, the bar is lower, but the description still provides no value beyond the action itself.

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 a single concise sentence with no filler. It front-loads the primary action and resource. For a simple tool, this is appropriately sized and structured.

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?

The tool is simple (two parameters, one action), but the description is missing key context: it doesn't clarify whether the material must exist beforehand, and it doesn't distinguish itself from the sibling rhino_assign_material. The output schema is marked as present, so return values may be covered there, but the description alone is minimally complete. It is adequate for a trivial operation but leaves the agent to infer usage conditions.

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 schema already documents both parameters ('GUIDs of objects' and 'Material name to assign'). Since schema description coverage is high (both parameters have descriptions), the baseline is 3. The description adds no extra parameter semantics, so it stays at the baseline.

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 clear action ('Assign a named material') on a specific resource ('objects'). However, it does not differentiate from the sibling tool rhino_assign_material, which appears to serve a similar purpose. The verb and resource are clear, but without distinguishing from the sibling, it cannot get a 5.

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?

There is no guidance on when to use this tool versus alternatives like rhino_assign_material or rhino_create_material. The description only says to assign a material, but doesn't mention scenarios, prerequisites, or when another tool would be more appropriate. This leaves the agent without clear selection criteria.

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