Draw a line segment in a Fusion 360 sketch by specifying start and end coordinates in millimeters. Define x1, y1, x2, y2 to create the line.
Draw a single line segment from (x1,y1) to (x2,y2), in mm.
| Name | Required | Description | Default |
|---|---|---|---|
| x1 | Yes | ||
| x2 | Yes | ||
| y1 | Yes | ||
| y2 | Yes | ||
| plane | No | xy | |
| sketch | No |
Changes observed during successful MCP inspections.
v0.6.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the description isn't required to repeat those. However, it adds no information about side effects beyond the basic draw, such as that the line is added to the active sketch or that openWorldHint might imply broader effects. The description provides minimal additional behavioral context beyond annotations.
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, front-loaded sentence that efficiently states the core action. It avoids redundancy and is appropriately short for a simple tool, though it could include more useful context without becoming verbose.
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 mutation tool with no output schema and openWorldHint=true, the description is too terse. It does not mention that the line is drawn in the active sketch, whether a sketch must exist first, how 'plane' affects the operation, or any prerequisites. This leaves the agent with significant unanswered questions for proper invocation.
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 for all parameters. It explains x1,y1,x2,y2 as coordinates and notes units (mm), but completely omits the 'plane' and 'sketch' parameters, which are optional but important for targeting the correct sketch plane. This is a significant gap given the zero coverage.
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 states a specific verb ('Draw'), a specific resource ('single line segment'), and the exact coordinates needed. It clearly distinguishes from sibling sketch tools like rectangle, circle, or spline by specifying a line segment, and even includes units (mm) which is helpful.
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 guidance is given on when to use this vs. other sketch tools (e.g., rectangle, spline) or any exclusions. The name implies it's for lines, but the description does not explicitly state when to choose it over alternatives, nor does it mention prerequisites like an active sketch.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.