Set the document's display length unit to millimeters, centimeters, meters, inches, or feet. Inputs remain in millimeters regardless of display setting.
Set the document's display length unit: mm/cm/m/in/ft. (Note: tool inputs are always in millimetres regardless of this display setting.)
| Name | Required | Description | Default |
|---|---|---|---|
| units | Yes |
Changes observed during successful MCP inspections.
v0.6.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Adds important note about tool inputs being always in millimeters, which is beyond annotations. Lists valid units. No contradiction.
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?
Extremely concise: one short sentence plus parenthetical note. No fluff, front-loaded with action and values.
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?
Fairly complete for a simple one-parameter tool; covers purpose, valid values, and an important behavioral note. Does not explain error handling or persistence.
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 coverage is 0%, description lists valid units but does not specify exact string format (e.g., 'mm' vs 'millimeter'). Partial compensation.
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?
Clearly states 'Set the document's display length unit' with a list of valid units. Distinguishes from sibling 'fusion_get_units'.
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?
No explicit guidance on when to use versus not use. Implicit from name and sibling, but lacks context-specific advice.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.