set_material_assignment

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

The [MODIFIES MODEL] prefix explicitly warns that this is a mutating operation, which is important given there are no annotations. Still, the description does not disclose whether an existing material assignment is overwritten, whether the body must already exist, or any side effects beyond the modification.

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, efficient sentence with the important mutation warning front-loaded. Every word earns its place and there is no redundant or vague 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 two-parameter setter, the description is mostly usable but leaves key invocation details unstated, such as valid material formats, overwrite behavior, and preconditions. The presence of an output schema reduces the need to document return values, so the overall context is adequate but not complete.

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 0%, so the description must compensate. It clarifies that body_name refers to a uniquely named body, but it adds no detail about material values, valid naming conventions, or how to obtain an appropriate material string. This is only minimal compensation for the missing parameter descriptions.

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 uses a specific verb ('Assign') and clear resource ('material') with a precise target ('one uniquely named body'). It communicates the core action effectively and distinguishes itself from read-oriented siblings like get_material_assignments, though it does not explicitly name an 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?

The description implies when to use the tool: when you want to set a material on a single named body. However, it provides no explicit guidance about alternatives, prerequisites, or situations where a different tool (e.g., get_material_assignments) would be more appropriate.

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