poly_assign_material_id

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

Annotations already declare readOnlyHint=false and destructiveHint=true, alerting the agent to the tool's mutating and potentially destructive nature. The description adds the behavioral clarification that faces sharing an ID also share a sub-material slot, but it does not go further into consequences like overwriting existing IDs. This is sufficient given the annotation coverage.

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 bilingual, front-loading the action and purpose. Every sentence carries relevant semantic information without filler, and the key sharing behavior is stated efficiently.

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 3-parameter tool with no output schema, the description covers the purpose and the key behavioral nuance (shared sub-material slot). It does not mention prerequisites like the object needing to be an editable poly, but the schema already conveys the optional nature of faces and objects, and this is adequate for straightforward use.

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 input schema has 100% coverage, documenting all three parameters (faces, objects, materialId) with clear descriptions including 'omit for all' and '1-based'. The tool description adds no extra parameter details, so the baseline of 3 applies.

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 the verb 'assign' and the resource 'material ID to selected faces', and explains the specific meaning in the context of multi/sub-object materials (faces with the same ID share a sub-material slot). This distinguishes it from sibling tools like mat_set_sub_material, which assign materials directly, and poly_set_smoothing, which affects smoothing groups.

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 phrase 'for multi/sub-object materials' provides clear context for when this tool is appropriate. It does not explicitly name alternatives or exclusions, but the use case is evident and no misleading guidance is present.

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