set_units

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

No annotations are provided, so the description carries the full burden of explaining side effects. It only states the purpose and parameter options, but does not mention that this mutates scene state, affects existing objects, or has any other behavioral consequences.

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 extremely concise and front-loaded, immediately identifying the tool's purpose. Every sentence adds value, and there is no redundant or irrelevant content.

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 description provides enough context to understand the tool's basic purpose and allowed values, but it omits important details such as default values, whether the change is global or per-scene, and what happens to existing measurements. Given the simple nature of the tool, this 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?

The description clarifies three of the four parameters by listing example values (system, length_unit, rotation_unit), but scale_length is not described at all. This partially compensates for the lack of schema descriptions but leaves one parameter ambiguous.

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 tool sets scene units, with the verb 'set' and resource 'units' explicitly identified. It distinguishes itself from sibling tools by focusing specifically on unit configuration, which no other sibling covers.

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 gives useful parameter value examples (METRIC/IMPERIAL/NONE, DEGREES/RADIANS), implying when the tool should be used to configure scene units. However, it does not explicitly mention alternatives or conditions for when not to use it.

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