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CDT AutoCAD Provider

CDT AutoCAD Provider

by SlncTrZ
OverviewSchemaSourceRelated ServersDiscussionsAdmin
Python
Hybrid

entity_create_arc

Create an ARC entity in the active drawing space using a WCS center, positive radius, and start/end angles in degrees.

Instructions

Create an ARC at a WCS center with positive radius; start_angle and end_angle are degrees and the result is a new drawing object.

Side-effects: Adds ARC entity to active space. Disambiguation: Use for circular arcs in degrees; for full circles use entity_create_circle.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "cx": "<cx>",
      "cy": "<cy>",
      "radius": "<radius>",
      "start_angle": "<start_angle>",
      "end_angle": "<end_angle>"
    },
    "name": "entity_create_arc"
  }
}

Input Schema

NameRequiredDescriptionDefault
cxYesCenter X coordinate in WCS drawing units
cyYesCenter Y coordinate in WCS drawing units
colorNoAutoCAD Color Index (ACI 1-255). Uses ByLayer if omitted
layerNoTarget layer name. Uses active layer if omitted
radiusYesPositive arc radius in drawing units
end_angleYesEnd angle in degrees (counter-clockwise from +X axis)
start_angleYesStart angle in degrees (counter-clockwise from +X axis)

Output Schema

NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed7 schema fields changedv0.1.1
    • addedInput schema / properties / color / description
      Added value: +"AutoCAD Color Index (ACI 1-255). Uses ByLayer if omitted"
    • addedInput schema / properties / cx / description
      Added value: +"Center X coordinate in WCS drawing units"
    • addedInput schema / properties / cy / description
      Added value: +"Center Y coordinate in WCS drawing units"
    • addedInput schema / properties / end_angle / description
      Added value: +"End angle in degrees (counter-clockwise from +X axis)"
    • addedInput schema / properties / layer / description
      Added value: +"Target layer name. Uses active layer if omitted"
    • addedInput schema / properties / radius / description
      Added value: +"Positive arc radius in drawing units"
    • addedInput schema / properties / start_angle / description
      Added value: +"Start angle in degrees (counter-clockwise from +X axis)"
  2. First observedv0.1.0

TDQS

A4.2/5.0
Behavior4/5

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

Annotations only declare readOnlyHint=false, so the description carries most of the burden and does so: it discloses the side-effect ('Adds ARC entity to active space') and that the call returns a new drawing object. It still omits whether this is undoable or requires a transaction, but the mutation effect is clearly stated.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The core verb/resource sentence is front-loaded, and the side-effect and disambiguation lines are labeled so an agent can scan them in order. No sentence is filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With a full output schema and complete parameter docs, the main remaining gap for a creation tool is transactional scope, which is not addressed. The side-effect and alternative-tool notes cover the essentials an agent needs to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all seven parameters including layer and color defaults are already documented. The description restates the degree units and positive-radius constraint, which duplicates the schema rather than adding new meaning, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource ('Create an ARC at a WCS center') and pins down the defining parameters (positive radius, start/end angles in degrees). It explicitly names the sibling it is not, so an agent can separate it from entity_create_circle without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The disambiguation line states the selection rule: use this for circular arcs in degrees, use entity_create_circle for full circles. That is a concrete alternative with a condition, though there is no guidance on related cases such as polylines or ellipse-like geometry.

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

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