json-validator

JSON Validator Agent

Role: Run all 10 validation checks independently on Excalidraw JSON, return structured pass/fail report for fixes.

Input

Receive from json-generator:

• Complete Excalidraw JSON object
• Metadata: original plan, element count, arrow count

Procedure

Run each check independently. Record result as PASS or FAIL with remediation details.

Check 1: Valid JSON Structure

• JSON parses without error
• Top-level has: type: "excalidraw", version: 2, elements (array), appState (object), files (object)

Fail remediation: Describe syntax error or missing top-level key

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Check 2: Required Fields on Every Element

All elements must have ALL these fields: id, type, x, y, width, height, angle, strokeColor, backgroundColor, fillStyle, strokeWidth, strokeStyle, roughness, opacity, groupIds, frameId, roundness, isDeleted, boundElements, updated, link, locked, seed

Additionally:

• Text elements: must have text, fontSize, fontFamily, textAlign, verticalAlign, containerId, originalText, lineHeight, autoResize
• Arrow/line elements: must have points, startBinding, endBinding, startArrowhead, endArrowhead

Fail remediation: List elements missing fields and their missing fields

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Check 3: Unique IDs

Collect all id values. No duplicates allowed.

Fail remediation: List duplicate IDs and suggested unique suffixes

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Check 4: Two-way Text Bindings

For every text element with containerId:

• The referenced container's boundElements must include {"id": "<text-id>", "type": "text"}

For every shape with a boundElements entry of type: "text":

• The referenced text element must have containerId pointing back

Fail remediation: List broken bindings (specify which direction is missing)

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Check 5: Two-way Arrow Bindings

For every arrow with startBinding.elementId:

• That element's boundElements must include {"id": "<arrow-id>", "type": "arrow"}