kernelcad

Add Pattern Feature

add_pattern_feature

Use this when you need to repeat a feature in a pattern. Insert a Shape.patternLinear / .patternCircular / .patternGrid call into a kernelCAD script before the last top-level return. Pass structured args (kind + the matching spec object). Returns the modified code plus diagnostics from re-evaluating. Side-effect-free. The pattern feature is a single editable unit; pattern-instance face refs resolve via <sourceId>_pattern_<i> on the pattern feature's lineage. Geometric note: pattern is implemented as cumulative boolean union of transformed source copies — additive features (boxes, ribs, fins, spokes) pattern cleanly; patterning a subtractive feature (hole, cutout) only preserves the per-instance void when adjacent bodies are disjoint.

Input Schema

TableJSON Schema

Name	Required	Description
`code`	Yes	The .kcad.ts source code.
`grid`	No	Required when kind=grid.
`kind`	Yes
`linear`	No	Required when kind=linear.
`target`	Yes	Variable name of the Shape to pattern (inserted verbatim as the LHS receiver).
`circular`	No	Required when kind=circular.
`assign_to`	No	Optional const-binding name; emits `const <assign_to> = <target>.patternX(...);`. Omit for statement form.

Output Schema

TableJSON Schema

Name	Required	Description
`ok`	Yes	Whether the edit applied and re-evaluated cleanly.
`error`	No	Failure message (present when ok is false).
`new_code`	No	Modified .kcad.ts source (present on success). Caller persists it.
`diagnostics`	No	Diagnostics from re-evaluating the modified source.
`binding_name`	No	JS const name bound to the new construct (when one was created).

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

Changed7 schema fields changedJun 19, 2026

addedInput schema / allOf

Added value: +[
+  {
+    "if": {
+      "properties": {
+        "kind": {
+          "const": "linear"
+        }
+      }
+    },
+    "then": {
+      "required": [
+        "linear"
+      ]
+    }
+  },
+  {
+    "if": {
+      "properties": {
+        "kind": {
+          "const": "circular"
+        }
+      }
+    },
+    "then": {
+      "required": [
+        "circular"
+      ]
+    }
+  },
+  {
+    "if": {
+      "properties": {
+        "kind": {
+          "const": "grid"
+        }
+      }
+    },
+    "then": {
+      "required": [
+        "grid"
+      ]
+    }
+  }
+]

addedInput schema / properties / grid / properties / x / description
```
Added value: +"First grid axis."
```

addedInput schema / properties / grid / properties / x / properties

Added value: +{
+  "count": {
+    "minimum": 2,
+    "type": "integer"
+  },
+  "direction": {
+    "items": {
+      "type": "number"
+    },
+    "maxItems": 3,
+    "minItems": 3,
+    "type": "array"
+  },
+  "spacing": {
+    "type": "number"
+  }
+}

addedInput schema / properties / grid / properties / x / required
```
Added value: +[
+  "count",
+  "direction",
+  "spacing"
+]
```
addedInput schema / properties / grid / properties / y / description
```
Added value: +"Second grid axis."
```

addedInput schema / properties / grid / properties / y / properties

Added value: +{
+  "count": {
+    "minimum": 2,
+    "type": "integer"
+  },
+  "direction": {
+    "items": {
+      "type": "number"
+    },
+    "maxItems": 3,
+    "minItems": 3,
+    "type": "array"
+  },
+  "spacing": {
+    "type": "number"
+  }
+}

addedInput schema / properties / grid / properties / y / required
```
Added value: +[
+  "count",
+  "direction",
+  "spacing"
+]
```

Changed7 schema fields changedJun 19, 2026

removedInput schema / allOf

Removed value: -[
-  {
-    "if": {
-      "properties": {
-        "kind": {
-          "const": "linear"
-        }
-      }
-    },
-    "then": {
-      "required": [
-        "linear"
-      ]
-    }
-  },
-  {
-    "if": {
-      "properties": {
-        "kind": {
-          "const": "circular"
-        }
-      }
-    },
-    "then": {
-      "required": [
-        "circular"
-      ]
-    }
-  },
-  {
-    "if": {
-      "properties": {
-        "kind": {
-          "const": "grid"
-        }
-      }
-    },
-    "then": {
-      "required": [
-        "grid"
-      ]
-    }
-  }
-]

removedInput schema / properties / grid / properties / x / description
```
Removed value: -"First grid axis."
```

removedInput schema / properties / grid / properties / x / properties

Removed value: -{
-  "count": {
-    "minimum": 2,
-    "type": "integer"
-  },
-  "direction": {
-    "items": {
-      "type": "number"
-    },
-    "maxItems": 3,
-    "minItems": 3,
-    "type": "array"
-  },
-  "spacing": {
-    "type": "number"
-  }
-}

removedInput schema / properties / grid / properties / x / required
```
Removed value: -[
-  "count",
-  "direction",
-  "spacing"
-]
```
removedInput schema / properties / grid / properties / y / description
```
Removed value: -"Second grid axis."
```

removedInput schema / properties / grid / properties / y / properties

Removed value: -{
-  "count": {
-    "minimum": 2,
-    "type": "integer"
-  },
-  "direction": {
-    "items": {
-      "type": "number"
-    },
-    "maxItems": 3,
-    "minItems": 3,
-    "type": "array"
-  },
-  "spacing": {
-    "type": "number"
-  }
-}

removedInput schema / properties / grid / properties / y / required
```
Removed value: -[
-  "count",
-  "direction",
-  "spacing"
-]
```

Changed7 schema fields changedJun 15, 2026

addedInput schema / allOf

Added value: +[
+  {
+    "if": {
+      "properties": {
+        "kind": {
+          "const": "linear"
+        }
+      }
+    },
+    "then": {
+      "required": [
+        "linear"
+      ]
+    }
+  },
+  {
+    "if": {
+      "properties": {
+        "kind": {
+          "const": "circular"
+        }
+      }
+    },
+    "then": {
+      "required": [
+        "circular"
+      ]
+    }
+  },
+  {
+    "if": {
+      "properties": {
+        "kind": {
+          "const": "grid"
+        }
+      }
+    },
+    "then": {
+      "required": [
+        "grid"
+      ]
+    }
+  }
+]

addedInput schema / properties / grid / properties / x / description
```
Added value: +"First grid axis."
```

addedInput schema / properties / grid / properties / x / properties

Added value: +{
+  "count": {
+    "minimum": 2,
+    "type": "integer"
+  },
+  "direction": {
+    "items": {
+      "type": "number"
+    },
+    "maxItems": 3,
+    "minItems": 3,
+    "type": "array"
+  },
+  "spacing": {
+    "type": "number"
+  }
+}

addedInput schema / properties / grid / properties / x / required
```
Added value: +[
+  "count",
+  "direction",
+  "spacing"
+]
```
addedInput schema / properties / grid / properties / y / description
```
Added value: +"Second grid axis."
```

addedInput schema / properties / grid / properties / y / properties

Added value: +{
+  "count": {
+    "minimum": 2,
+    "type": "integer"
+  },
+  "direction": {
+    "items": {
+      "type": "number"
+    },
+    "maxItems": 3,
+    "minItems": 3,
+    "type": "array"
+  },
+  "spacing": {
+    "type": "number"
+  }
+}

addedInput schema / properties / grid / properties / y / required
```
Added value: +[
+  "count",
+  "direction",
+  "spacing"
+]
```

Changed1 schema field changedJun 15, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "additionalProperties": true,
+  "properties": {
+    "binding_name": {
+      "description": "JS const name bound to the new construct (when one was created).",
+      "type": "string"
+    },
+    "diagnostics": {
+      "description": "Diagnostics from re-evaluating the modified source.",
+      "items": {
+        "additionalProperties": true,
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "error": {
+      "description": "Failure message (present when ok is false).",
+      "type": "string"
+    },
+    "new_code": {
+      "description": "Modified .kcad.ts source (present on success). Caller persists it.",
+      "type": "string"
+    },
+    "ok": {
+      "description": "Whether the edit applied and re-evaluated cleanly.",
+      "type": "boolean"
+    }
+  },
+  "required": [
+    "ok"
+  ],
+  "type": "object"
+}

First observedMay 25, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Discloses side-effect-free nature, return value (modified code + diagnostics), pattern implementation as cumulative boolean union, and face ref naming convention. Annotations are consistent (readOnlyHint false, destructiveHint false).

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

Conciseness4/5

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

The description is a single well-structured paragraph, front-loading the core purpose, then covering insertion behavior, returns, side-effects, and geometric notes. Slightly verbose but each sentence adds value.

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

Completeness5/5

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

Given the tool's complexity (7 params, nested objects, output schema exists), the description covers return value, side-effect-free nature, pattern unit concept, geometric implications, and face ref naming. It is complete for correct agent usage.

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

Parameters4/5

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

Schema coverage is 86%, so the schema already documents most parameters. The description adds value by explaining the role of 'target', 'assign_to', and the return value, but does not re-iterate all schema details.

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 clearly states it repeats a feature in a pattern by inserting a pattern call into a script. It distinguishes from siblings like add_feature (general feature addition) and flatten_pattern (different operation).

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

Usage Guidelines5/5

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

Explicitly says 'Use this when you need to repeat a feature in a pattern' and provides context on when each pattern kind is appropriate via the schema. Also gives guidance on additive vs subtractive features.

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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TDQS

A3.9/5.0

Disambiguation4/5

Tools are mostly distinct, with clear descriptions for each. However, there is some potential overlap between inspection tools like 'inspect' and 'mesh_summary', and between rendering tools 'render_preview' and 'get_latest_render', which could cause minor confusion.

Naming Consistency5/5

All tool names follow a consistent snake_case verb_noun pattern, making it predictable for an agent to infer functionality.

Tool Count2/5

44 tools is significantly higher than the typical well-scoped range of 3-15. While the domain is complex, the count feels excessive and could overwhelm an agent.

Completeness4/5

The tool set covers an extensive range of CAD operations including creation, inspection, rendering, export, and verification. Minor gaps exist, such as direct sketch editing tools, but overall it is comprehensive.

Add Pattern Feature

Input Schema

Output Schema

Schema Changelog

TDQS

Glama MCP Gateway

TDQS

Resources