Font Design MCP

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font_edit

Edit up to 128 glyphs atomically in a font master and apply spacing; validation failures roll back the entire batch to keep outlines consistent.

Instructions

Edit up to 128 glyphs atomically in master_id (default: 'default'), then apply spacing. Forward component references resolve at final validation; any failure rolls back the batch.

Input Schema

TableJSON Schema

Name	Required	Default
`detail`	No	summary
`glyphs`	Yes
`spacing`	No
`summary`	No
`master_id`	No	default
`project_id`	Yes
`expected_revision`	Yes

Output Schema

TableJSON Schema

Name	Required	Description	Default
`ok`	Yes
`data`	No
`error`	No
`changed`	No
`summary`	Yes
`revision`	No
`warnings`	No
`project_id`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed9 schema fields changedv0.6.0Sep 12, 2026

addedInput schema / $defs / DetachStrokeNetwork

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "op": {
+      "const": "detach_stroke_network",
+      "type": "string"
+    }
+  },
+  "required": [
+    "op"
+  ],
+  "type": "object"
+}

addedInput schema / $defs / GlyphChange / properties / operations / items / discriminator / mapping / detach_stroke_network
```
Added value: +"#/$defs/DetachStrokeNetwork"
```
addedInput schema / $defs / GlyphChange / properties / operations / items / discriminator / mapping / stroke_network
```
Added value: +"#/$defs/SetStrokeNetwork"
```
addedInput schema / $defs / GlyphChange / properties / operations / items / discriminator / mapping / update_stroke_network
```
Added value: +"#/$defs/UpdateStrokeNetwork"
```

changedInput schema / $defs / GlyphChange / properties / operations / items / oneOf

Previous value: -[
-  {
-    "$ref": "#/$defs/PutContour"
-  },
-  {
-    "$ref": "#/$defs/MovePoint"
-  },
-  {
-    "$ref": "#/$defs/MoveHandle"
-  },
-  {
-    "$ref": "#/$defs/SetSmooth"
-  },
-  {
-    "$ref": "#/$defs/DetachComposition"
-  },
-  {
-    "$ref": "#/$defs/Transform"
-  },
-  {
-    "$ref": "#/$defs/PutComponent"
-  },
-  {
-    "$ref": "#/$defs/PutAnchor"
-  },
-  {
-    "$ref": "#/$defs/Remove"
-  },
-  {
-    "$ref": "#/$defs/SetUnicodes"
-  },
-  {
-    "$ref": "#/$defs/ReplaceGlyph"
-  },
-  {
-    "$ref": "#/$defs/FilledPath"
-  },
-  {
-    "$ref": "#/$defs/StrokePath"
-  },
-  {
-    "$ref": "#/$defs/Primitive"
-  },
-  {
-    "$ref": "#/$defs/Duplicate"
-  },
-  {
-    "$ref": "#/$defs/ComposeAccent"
-  }
-]New value: +[
+  {
+    "$ref": "#/$defs/PutContour"
+  },
+  {
+    "$ref": "#/$defs/MovePoint"
+  },
+  {
+    "$ref": "#/$defs/MoveHandle"
+  },
+  {
+    "$ref": "#/$defs/SetSmooth"
+  },
+  {
+    "$ref": "#/$defs/DetachComposition"
+  },
+  {
+    "$ref": "#/$defs/Transform"
+  },
+  {
+    "$ref": "#/$defs/PutComponent"
+  },
+  {
+    "$ref": "#/$defs/PutAnchor"
+  },
+  {
+    "$ref": "#/$defs/Remove"
+  },
+  {
+    "$ref": "#/$defs/SetUnicodes"
+  },
+  {
+    "$ref": "#/$defs/ReplaceGlyph"
+  },
+  {
+    "$ref": "#/$defs/FilledPath"
+  },
+  {
+    "$ref": "#/$defs/StrokePath"
+  },
+  {
+    "$ref": "#/$defs/SetStrokeNetwork"
+  },
+  {
+    "$ref": "#/$defs/UpdateStrokeNetwork"
+  },
+  {
+    "$ref": "#/$defs/DetachStrokeNetwork"
+  },
+  {
+    "$ref": "#/$defs/Primitive"
+  },
+  {
+    "$ref": "#/$defs/Duplicate"
+  },
+  {
+    "$ref": "#/$defs/ComposeAccent"
+  }
+]

addedInput schema / $defs / NetworkStroke

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "cap": {
+      "default": "butt",
+      "enum": [
+        "round",
+        "butt",
+        "square"
+      ],
+      "type": "string"
+    },
+    "id": {
+      "pattern": "^[a-zA-Z_][a-zA-Z0-9_]{0,15}$",
+      "type": "string"
+    },
+    "join": {
+      "default": "miter",
+      "enum": [
+        "round",
+        "bevel",
+        "miter"
+      ],
+      "type": "string"
+    },
+    "path": {
+      "maxLength": 16000,
+      "minLength": 1,
+      "type": "string"
+    },
+    "width_parameter": {
+      "pattern": "^[a-zA-Z0-9_][a-zA-Z0-9_.-]{0,63}$",
+      "type": "string"
+    }
+  },
+  "required": [
+    "id",
+    "path",
+    "width_parameter"
+  ],
+  "type": "object"
+}

addedInput schema / $defs / SetStrokeNetwork

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "network": {
+      "$ref": "#/$defs/StrokeNetwork"
+    },
+    "op": {
+      "const": "stroke_network",
+      "type": "string"
+    },
+    "replace": {
+      "default": false,
+      "type": "boolean"
+    }
+  },
+  "required": [
+    "op",
+    "network"
+  ],
+  "type": "object"
+}

addedInput schema / $defs / StrokeNetwork

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "advance": {
+      "default": 600,
+      "maximum": 16000,
+      "minimum": 0,
+      "type": "number"
+    },
+    "horizontal_scale": {
+      "default": 1,
+      "exclusiveMinimum": 0,
+      "maximum": 4,
+      "type": "number"
+    },
+    "origin_x": {
+      "default": 0,
+      "maximum": 16000,
+      "minimum": -16000,
+      "type": "number"
+    },
+    "parameters": {
+      "maxProperties": 16,
+      "minProperties": 1,
+      "patternProperties": {
+        "^[a-zA-Z0-9_][a-zA-Z0-9_.-]{0,63}$": {
+          "exclusiveMinimum": 0,
+          "maximum": 2000,
+          "type": "number"
+        }
+      },
+      "type": "object"
+    },
+    "strokes": {
+      "items": {
+        "$ref": "#/$defs/NetworkStroke"
+      },
+      "maxItems": 16,
+      "minItems": 1,
+      "type": "array"
+    }
+  },
+  "required": [
+    "parameters",
+    "strokes"
+  ],
+  "type": "object"
+}

addedInput schema / $defs / UpdateStrokeNetwork

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "advance": {
+      "anyOf": [
+        {
+          "maximum": 16000,
+          "minimum": 0,
+          "type": "number"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "horizontal_scale": {
+      "anyOf": [
+        {
+          "exclusiveMinimum": 0,
+          "maximum": 4,
+          "type": "number"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null
+    },
+    "op": {
+      "const": "update_stroke_network",
+      "type": "string"
+    },
+    "parameters": {
+      "maxProperties": 16,
+      "patternProperties": {
+        "^[a-zA-Z0-9_][a-zA-Z0-9_.-]{0,63}$": {
+          "exclusiveMinimum": 0,
+          "maximum": 2000,
+          "type": "number"
+        }
+      },
+      "type": "object"
+    }
+  },
+  "required": [
+    "op"
+  ],
+  "type": "object"
+}

Changed9 schema fields changedv0.5.0Sep 10, 2026

addedInput schema / $defs / ComposeAccent / properties / auto_align
```
Added value: +{
+  "default": false,
+  "type": "boolean"
+}
```

addedInput schema / $defs / DetachComposition

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "op": {
+      "const": "detach_composition",
+      "type": "string"
+    }
+  },
+  "required": [
+    "op"
+  ],
+  "type": "object"
+}

addedInput schema / $defs / GlyphChange / properties / operations / items / discriminator / mapping / detach_composition
```
Added value: +"#/$defs/DetachComposition"
```
addedInput schema / $defs / GlyphChange / properties / operations / items / discriminator / mapping / move_handle
```
Added value: +"#/$defs/MoveHandle"
```
addedInput schema / $defs / GlyphChange / properties / operations / items / discriminator / mapping / set_smooth
```
Added value: +"#/$defs/SetSmooth"
```

changedInput schema / $defs / GlyphChange / properties / operations / items / oneOf

Previous value: -[
-  {
-    "$ref": "#/$defs/PutContour"
-  },
-  {
-    "$ref": "#/$defs/MovePoint"
-  },
-  {
-    "$ref": "#/$defs/Transform"
-  },
-  {
-    "$ref": "#/$defs/PutComponent"
-  },
-  {
-    "$ref": "#/$defs/PutAnchor"
-  },
-  {
-    "$ref": "#/$defs/Remove"
-  },
-  {
-    "$ref": "#/$defs/SetUnicodes"
-  },
-  {
-    "$ref": "#/$defs/ReplaceGlyph"
-  },
-  {
-    "$ref": "#/$defs/FilledPath"
-  },
-  {
-    "$ref": "#/$defs/StrokePath"
-  },
-  {
-    "$ref": "#/$defs/Primitive"
-  },
-  {
-    "$ref": "#/$defs/Duplicate"
-  },
-  {
-    "$ref": "#/$defs/ComposeAccent"
-  }
-]New value: +[
+  {
+    "$ref": "#/$defs/PutContour"
+  },
+  {
+    "$ref": "#/$defs/MovePoint"
+  },
+  {
+    "$ref": "#/$defs/MoveHandle"
+  },
+  {
+    "$ref": "#/$defs/SetSmooth"
+  },
+  {
+    "$ref": "#/$defs/DetachComposition"
+  },
+  {
+    "$ref": "#/$defs/Transform"
+  },
+  {
+    "$ref": "#/$defs/PutComponent"
+  },
+  {
+    "$ref": "#/$defs/PutAnchor"
+  },
+  {
+    "$ref": "#/$defs/Remove"
+  },
+  {
+    "$ref": "#/$defs/SetUnicodes"
+  },
+  {
+    "$ref": "#/$defs/ReplaceGlyph"
+  },
+  {
+    "$ref": "#/$defs/FilledPath"
+  },
+  {
+    "$ref": "#/$defs/StrokePath"
+  },
+  {
+    "$ref": "#/$defs/Primitive"
+  },
+  {
+    "$ref": "#/$defs/Duplicate"
+  },
+  {
+    "$ref": "#/$defs/ComposeAccent"
+  }
+]

addedInput schema / $defs / MoveHandle

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "mode": {
+      "default": "aligned",
+      "enum": [
+        "aligned",
+        "symmetric"
+      ],
+      "type": "string"
+    },
+    "op": {
+      "const": "move_handle",
+      "type": "string"
+    },
+    "point_id": {
+      "pattern": "^[a-zA-Z0-9_][a-zA-Z0-9_.-]{0,63}$",
+      "type": "string"
+    },
+    "x": {
+      "maximum": 16000,
+      "minimum": -16000,
+      "type": "number"
+    },
+    "y": {
+      "maximum": 16000,
+      "minimum": -16000,
+      "type": "number"
+    }
+  },
+  "required": [
+    "op",
+    "point_id",
+    "x",
+    "y"
+  ],
+  "type": "object"
+}

addedInput schema / $defs / MovePoint / properties / preserve_handles
```
Added value: +{
+  "default": false,
+  "type": "boolean"
+}
```

addedInput schema / $defs / SetSmooth

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "op": {
+      "const": "set_smooth",
+      "type": "string"
+    },
+    "point_id": {
+      "pattern": "^[a-zA-Z0-9_][a-zA-Z0-9_.-]{0,63}$",
+      "type": "string"
+    },
+    "smooth": {
+      "type": "boolean"
+    }
+  },
+  "required": [
+    "op",
+    "point_id",
+    "smooth"
+  ],
+  "type": "object"
+}

Addedv0.4.3Sep 9, 2026

TDQS

B3.4/5.0

Behavior4/5

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

Annotations cover the safety profile (readOnly=false, idempotent=false, destructive=false), and the description adds real behavior beyond them: atomicity, rollback on any failure, and deferred resolution of forward component references at final validation. That last point materially affects how a caller sequences dependent operations.

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?

Two tightly packed sentences, front-loaded with the action and scope, then the correctness guarantees. No filler and no repetition of structured data beyond the master_id default.

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

Completeness2/5

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

For a mutation tool with a very large nested schema and no output-value burden (an output schema exists), the description is too thin: it omits expected_revision semantics, the create flag on GlyphChange, and any sense of what the glyphs/spacing operation payloads do. Adequate for safety, inadequate for invocation.

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

Parameters2/5

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

Schema description coverage is 0% across 7 parameters, and the description explains only master_id (including its default). The heavyweight inputs the agent must construct – glyphs with its 19-way operation union, spacing, project_id, expected_revision, summary, detail – are left entirely to the schema, and expected_revision's optimistic-concurrency role is never stated.

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

Purpose4/5

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

States a specific verb (edit), resource (glyphs), and scope (up to 128, atomically in master_id, plus spacing). This distinguishes it from glyph_edit and spacing_edit implicitly via the batch/atomic/covers-both framing, but it never names a sibling to route the agent.

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

Usage Guidelines3/5

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

No explicit when-to-use or when-not-to-use statement. The atomic 128-glyph batch with a trailing spacing pass implies the use case is bulk edits, but an agent must infer this and has no guidance on choosing between font_edit, glyph_edit, and spacing_edit.

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