kernelcad

Add Mate

add_mate

Use this when you need to author a mate-graph relationship into the source, selected by relation (default 'mate'):

'mate' — a typed mate between two connectors ({ name, a, b, type, pose?, limitsDeg?, limitsMm? }).
'coupling' — couple a driven mate to a source mate by ratio ({ driven, source, ratio, offset? }).
'transmission' — a physical drive path across mates ({ name, kind, sourceMate, drivenMates, path, ... }). All durably edit source and need { code, assembly_binding }. Params other than relation are forwarded verbatim; each relation fails closed on its own missing required params.

Input Schema

TableJSON Schema

Name	Required	Description
`a`	No	relation:'mate' — connector ref "<partName>.<connectorName>".
`b`	No	relation:'mate' — connector ref "<partName>.<connectorName>".
`code`	Yes	The .kcad.ts source code.
`kind`	No	relation:'transmission' — transmission kind.
`name`	No	relation:'mate'\|'transmission' — name unique within the assembly.
`path`	No	relation:'transmission' — drive path.
`pose`	No	relation:'mate' — optional mate pose.
`type`	No	relation:'mate' — mate type.
`input`	No	relation:'transmission' — optional input.
`notes`	No	relation:'transmission' — optional notes.
`ratio`	No	relation:'coupling' — driven pose = source pose * ratio + offset.
`driven`	No	relation:'coupling' — driven mate name.
`offset`	No	relation:'coupling' — optional pose offset.
`output`	No	relation:'transmission' — optional output.
`source`	No	relation:'coupling' — source mate name.
`actuator`	No	relation:'transmission' — optional actuator.
`limitsMm`	No	relation:'mate' — optional [minMm, maxMm].
`relation`	No	Which relationship to author (default 'mate').
`limitsDeg`	No	relation:'mate' — optional [minDeg, maxDeg].
`sourceMate`	No	relation:'transmission' — source mate name.
`drivenMates`	No	relation:'transmission' — driven mate names.
`assembly_binding`	Yes	JS identifier bound to assembly(...).

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.

Changed1 schema field changedJul 18, 2026

changedInput schema / allOf

Previous value: -[
-  {
-    "if": {
-      "properties": {
-        "relation": {
-          "const": "coupling"
-        }
-      },
-      "required": [
-        "relation"
-      ]
-    },
-    "then": {
-      "required": [
-        "driven",
-        "source",
-        "ratio"
-      ]
-    }
-  },
-  {
-    "if": {
-      "properties": {
-        "relation": {
-          "const": "transmission"
-        }
-      },
-      "required": [
-        "relation"
-      ]
-    },
-    "then": {
-      "required": [
-        "name",
-        "kind",
-        "sourceMate",
-        "drivenMates",
-        "path"
-      ]
-    }
-  },
-  {
-    "else": {
-      "required": [
-        "name",
-        "a",
-        "b",
-        "type"
-      ]
-    },
-    "if": {
-      "properties": {
-        "relation": {
-          "enum": [
-            "coupling",
-            "transmission"
-          ]
-        }
-      },
-      "required": [
-        "relation"
-      ]
-    },
-    "then": {}
-  }
-]New value: +[
+  {
+    "if": {
+      "anyOf": [
+        {
+          "not": {
+            "required": [
+              "relation"
+            ]
+          }
+        },
+        {
+          "properties": {
+            "relation": {
+              "const": "mate"
+            }
+          },
+          "required": [
+            "relation"
+          ]
+        }
+      ]
+    },
+    "then": {
+      "required": [
+        "name",
+        "a",
+        "b",
+        "type"
+      ]
+    }
+  },
+  {
+    "if": {
+      "properties": {
+        "relation": {
+          "const": "coupling"
+        }
+      },
+      "required": [
+        "relation"
+      ]
+    },
+    "then": {
+      "required": [
+        "driven",
+        "source",
+        "ratio"
+      ]
+    }
+  },
+  {
+    "if": {
+      "properties": {
+        "relation": {
+          "const": "transmission"
+        }
+      },
+      "required": [
+        "relation"
+      ]
+    },
+    "then": {
+      "required": [
+        "name",
+        "kind",
+        "sourceMate",
+        "drivenMates",
+        "path"
+      ]
+    }
+  }
+]

Changed1 schema field changedJun 19, 2026

addedInput schema / allOf

Added value: +[
+  {
+    "if": {
+      "properties": {
+        "relation": {
+          "const": "coupling"
+        }
+      },
+      "required": [
+        "relation"
+      ]
+    },
+    "then": {
+      "required": [
+        "driven",
+        "source",
+        "ratio"
+      ]
+    }
+  },
+  {
+    "if": {
+      "properties": {
+        "relation": {
+          "const": "transmission"
+        }
+      },
+      "required": [
+        "relation"
+      ]
+    },
+    "then": {
+      "required": [
+        "name",
+        "kind",
+        "sourceMate",
+        "drivenMates",
+        "path"
+      ]
+    }
+  },
+  {
+    "else": {
+      "required": [
+        "name",
+        "a",
+        "b",
+        "type"
+      ]
+    },
+    "if": {
+      "properties": {
+        "relation": {
+          "enum": [
+            "coupling",
+            "transmission"
+          ]
+        }
+      },
+      "required": [
+        "relation"
+      ]
+    },
+    "then": {}
+  }
+]

Changed1 schema field changedJun 19, 2026

removedInput schema / allOf

Removed value: -[
-  {
-    "if": {
-      "properties": {
-        "relation": {
-          "const": "coupling"
-        }
-      },
-      "required": [
-        "relation"
-      ]
-    },
-    "then": {
-      "required": [
-        "driven",
-        "source",
-        "ratio"
-      ]
-    }
-  },
-  {
-    "if": {
-      "properties": {
-        "relation": {
-          "const": "transmission"
-        }
-      },
-      "required": [
-        "relation"
-      ]
-    },
-    "then": {
-      "required": [
-        "name",
-        "kind",
-        "sourceMate",
-        "drivenMates",
-        "path"
-      ]
-    }
-  },
-  {
-    "else": {
-      "required": [
-        "name",
-        "a",
-        "b",
-        "type"
-      ]
-    },
-    "if": {
-      "properties": {
-        "relation": {
-          "enum": [
-            "coupling",
-            "transmission"
-          ]
-        }
-      },
-      "required": [
-        "relation"
-      ]
-    },
-    "then": {}
-  }
-]

Changed1 schema field changedJun 15, 2026

addedInput schema / allOf

Added value: +[
+  {
+    "if": {
+      "properties": {
+        "relation": {
+          "const": "coupling"
+        }
+      },
+      "required": [
+        "relation"
+      ]
+    },
+    "then": {
+      "required": [
+        "driven",
+        "source",
+        "ratio"
+      ]
+    }
+  },
+  {
+    "if": {
+      "properties": {
+        "relation": {
+          "const": "transmission"
+        }
+      },
+      "required": [
+        "relation"
+      ]
+    },
+    "then": {
+      "required": [
+        "name",
+        "kind",
+        "sourceMate",
+        "drivenMates",
+        "path"
+      ]
+    }
+  },
+  {
+    "else": {
+      "required": [
+        "name",
+        "a",
+        "b",
+        "type"
+      ]
+    },
+    "if": {
+      "properties": {
+        "relation": {
+          "enum": [
+            "coupling",
+            "transmission"
+          ]
+        }
+      },
+      "required": [
+        "relation"
+      ]
+    },
+    "then": {}
+  }
+]

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"
+}

Changed26 schema fields changedJun 13, 2026

changedInput schema / properties / a / description

Previous value: -"Connector ref: \"<partName>.<connectorName>\" (legacy) or \"@kc[<partName>/connector/<connectorName>]\"."New value: +"relation:'mate' — connector ref \"<partName>.<connectorName>\"."

addedInput schema / properties / actuator

Added value: +{
+  "description": "relation:'transmission' — optional actuator.",
+  "type": "string"
+}

removedInput schema / properties / assembly

Removed value: -{
-  "type": "string"
-}

addedInput schema / properties / assembly_binding

Added value: +{
+  "description": "JS identifier bound to assembly(...).",
+  "type": "string"
+}

changedInput schema / properties / b / description

Previous value: -"Connector ref: \"<partName>.<connectorName>\" (legacy) or \"@kc[<partName>/connector/<connectorName>]\"."New value: +"relation:'mate' — connector ref \"<partName>.<connectorName>\"."

addedInput schema / properties / code

Added value: +{
+  "description": "The .kcad.ts source code.",
+  "type": "string"
+}

addedInput schema / properties / driven

Added value: +{
+  "description": "relation:'coupling' — driven mate name.",
+  "type": "string"
+}

addedInput schema / properties / drivenMates

Added value: +{
+  "description": "relation:'transmission' — driven mate names.",
+  "items": {
+    "type": "string"
+  },
+  "type": "array"
+}

addedInput schema / properties / input

Added value: +{
+  "description": "relation:'transmission' — optional input.",
+  "type": "string"
+}

addedInput schema / properties / kind

Added value: +{
+  "description": "relation:'transmission' — transmission kind.",
+  "enum": [
+    "direct-horn",
+    "link-rod",
+    "four-bar",
+    "gear-pair",
+    "belt",
+    "tendon"
+  ],
+  "type": "string"
+}

changedInput schema / properties / limitsDeg / description

Previous value: -"Optional [minDeg, maxDeg] range for revolute/cylindrical/pin_slot mates."New value: +"relation:'mate' — optional [minDeg, maxDeg]."

addedInput schema / properties / limitsDeg / items
```
Added value: +{
+  "type": "number"
+}
```

changedInput schema / properties / limitsMm / description

Previous value: -"Optional [minMm, maxMm] range for prismatic mates."New value: +"relation:'mate' — optional [minMm, maxMm]."

addedInput schema / properties / limitsMm / items
```
Added value: +{
+  "type": "number"
+}
```

changedInput schema / properties / name / description

Previous value: -"Mate name (unique within the assembly)."New value: +"relation:'mate'|'transmission' — name unique within the assembly."

addedInput schema / properties / notes

Added value: +{
+  "description": "relation:'transmission' — optional notes.",
+  "type": "string"
+}

addedInput schema / properties / offset

Added value: +{
+  "description": "relation:'coupling' — optional pose offset.",
+  "type": "number"
+}

addedInput schema / properties / output

Added value: +{
+  "description": "relation:'transmission' — optional output.",
+  "type": "string"
+}

addedInput schema / properties / path

Added value: +{
+  "description": "relation:'transmission' — drive path.",
+  "items": {
+    "type": "string"
+  },
+  "type": "array"
+}

changedInput schema / properties / pose / description

Previous value: -"Optional mate pose: number for scalar mates or [x, y, z] degrees for ball mates."New value: +"relation:'mate' — optional mate pose."

addedInput schema / properties / ratio

Added value: +{
+  "description": "relation:'coupling' — driven pose = source pose * ratio + offset.",
+  "type": "number"
+}

addedInput schema / properties / relation

Added value: +{
+  "description": "Which relationship to author (default 'mate').",
+  "enum": [
+    "mate",
+    "coupling",
+    "transmission"
+  ],
+  "type": "string"
+}

addedInput schema / properties / source

Added value: +{
+  "description": "relation:'coupling' — source mate name.",
+  "type": "string"
+}

addedInput schema / properties / sourceMate

Added value: +{
+  "description": "relation:'transmission' — source mate name.",
+  "type": "string"
+}

addedInput schema / properties / type / description
```
Added value: +"relation:'mate' — mate type."
```

changedInput schema / required

Previous value: -[
-  "name",
-  "a",
-  "b",
-  "type"
-]New value: +[
+  "code",
+  "assembly_binding"
+]

Changed2 schema fields changedJun 7, 2026

changedInput schema / properties / a / description

Previous value: -"Connector ref \"<partName>.<connectorName>\"."New value: +"Connector ref: \"<partName>.<connectorName>\" (legacy) or \"@kc[<partName>/connector/<connectorName>]\"."

changedInput schema / properties / b / description

Previous value: -"Connector ref \"<partName>.<connectorName>\"."New value: +"Connector ref: \"<partName>.<connectorName>\" (legacy) or \"@kc[<partName>/connector/<connectorName>]\"."

First observedMay 25, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already indicate readOnlyHint=false and destructiveHint=false, so the tool is not read-only and not destructive. The description adds that it 'durably edit source' and requires code and assembly_binding, plus states that each relation 'fails closed on its own missing required params', providing useful behavioral insight 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.

Conciseness5/5

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

The description is concise (about 10 lines) with a clear front-loaded purpose statement and bullet-pointed breakdown of the three relation types. Every sentence adds value without redundancy. It is well-structured for quick comprehension.

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 (three distinct operations with many parameters), the description sufficiently covers all key aspects: the three relation types, their parameter shapes, common required params, and error behavior. An output schema exists so return values need not be described. The description stands alone as a complete guide for an AI agent.

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 100%, so baseline is 3. The description groups parameters by relation type (e.g., 'mate' expects { name, a, b, type, pose?, ... }), which adds structural meaning not explicit in the schema's conditional required blocks. It also explains that non-relation parameters are 'forwarded verbatim', clarifying how to use them.

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 the tool's purpose: 'author a mate-graph relationship into the source'. It breaks down into three specific relation types (mate, coupling, transmission) with distinct parameter sets. This distinctively distinguishes it from sibling tools like add_constraint or add_connector.

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 description opens with 'Use this when you need to author a mate-graph relationship', providing clear usage context. It mentions required parameters (code, assembly_binding) and the default relation. However, it does not explicitly compare to alternatives or state when not to use the tool.

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 Mate

Input Schema

Output Schema

Schema Changelog

TDQS

Glama MCP Gateway

TDQS

Resources