draw_lineCreate a line in the most recent Fusion 360 sketch by specifying start and end coordinates; use centimeters and degrees unless parameters define other units. Ideal for adding sketch geometry.
Draw a line in the most recent sketch. Unless a parameter says otherwise, lengths and coordinates are in cm (not mm) and angles in degrees.
| Name | Required | Description | Default |
|---|---|---|---|
| end_x | Yes | ||
| end_y | Yes | ||
| end_z | No | ||
| start_x | Yes | ||
| start_y | Yes | ||
| start_z | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the mutation profile is known. The description adds genuinely useful context not in structured fields: default units are cm (not mm) and angles are degrees. It does not, however, disclose failure modes (no sketch present) or which sketch is modified beyond 'most recent'.
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?
Two short sentences, front-loaded with the action before the convention caveat. Efficient overall, though the mention of angles in degrees earns little since this tool exposes no angle parameters.
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?
No output schema exists and annotations only cover the safety profile, so the description is the agent's main source of detail for a 6-parameter geometry mutation. It delivers the critical unit convention but leaves prerequisites (existing sketch) and the coordinate system unexplained, leaving gaps for a tool of this complexity.
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% across 6 parameters, so the description carries the full burden. It supplies the unit convention (cm) and mentions angles in degrees, but the actual parameters are all coordinates and there are no angle parameters, so that clause is largely irrelevant and the z-default behavior and coordinate origin remain unexplained.
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?
States a specific verb and resource ('Draw a line') and scopes it to 'the most recent sketch', which distinguishes it from the rectangle/circle/arc/spline siblings without needing to open a schema. It stops short of explicitly contrasting with those siblings, so it is clear but not maximally differentiated.
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 when-to-use or when-not-to-use guidance, and no alternative named (e.g., draw_spline for curves, draw_arc for arcs). The phrase 'in the most recent sketch' implies a sketch must already exist, but this prerequisite is only implicit rather than stated as a rule.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.