{
  "name": "preview_change",
  "description": "Dry-run a part source patch and return validation plus HTML/CSS diffs without saving. Use mode=source_patch first. This reuses the same patch, sanitization, and validation path as the real source patch write.",
  "http": {
    "method": "POST",
    "path": "/wp-json/uncanny-page-builder/v1/agent/part/preview"
  },
  "parameters": [
    {
      "name": "section_id",
      "type": "integer",
      "required": true,
      "in": "body",
      "description": "Section ID to preview."
    },
    {
      "name": "page_id",
      "type": "integer",
      "required": false,
      "in": "body",
      "description": "Uncanny Page Builder canvas page ID. Pass this when the user provides a canvas_id or a page_id known to be an Uncanny Page Builder canvas. For ordinary WordPress page URLs or names, resolve the target first; do not assume any page_id is editable. Omit to use the current page when a canvas is active."
    },
    {
      "name": "mode",
      "type": "string",
      "enum": ["source_patch"],
      "required": false,
      "in": "body",
      "description": "Preview mode. Use source_patch."
    },
    {
      "name": "html_patches",
      "type": "array",
      "required": false,
      "in": "body",
      "description": "Ordered exact HTML substring patches. Use {search:\"exact current non-empty HTML substring from read_part include=source\", replace:\"replacement HTML\"} to replace, {action:\"insert_after\", search:\"...\", content:\"...\"} or {action:\"insert_before\", search:\"...\", content:\"...\"} to insert, and {action:\"delete\", search:\"...\"} to delete. The search value must not be empty and must match exactly once in current HTML. Never use search:\"\"; use edit_part mode=source_replace for whole-source replacement.",
      "items": {
        "type": "object",
        "required": ["search"],
        "properties": {
          "action": {
            "type": "string",
            "enum": ["replace", "insert_after", "insert_before", "delete"],
            "description": "Patch action: replace, insert_after, insert_before, or delete. Defaults to replace."
          },
          "search": {
            "type": "string",
            "minLength": 1,
            "description": "Exact current non-empty HTML substring copied from read_part include=source. Must match exactly once."
          },
          "replace": {
            "type": "string",
            "description": "Replacement HTML for the matched search substring."
          },
          "content": {
            "type": "string",
            "description": "HTML to insert for insert_after or insert_before."
          }
        }
      }
    },
    {
      "name": "css_patches",
      "type": "array",
      "required": false,
      "in": "body",
      "description": "Ordered exact CSS substring patches. Use {search:\"exact current non-empty CSS substring from read_part include=source\", replace:\"replacement CSS\"} to replace, {action:\"insert_after\", search:\"...\", content:\"...\"} or {action:\"insert_before\", search:\"...\", content:\"...\"} to insert, and {action:\"delete\", search:\"...\"} to delete. Exact patch search must match once in current CSS. Prefer css_rules for selector declarations. If search is empty but replace/content is a complete selector block, the API treats it as css_rules. Keep CSS canvas-local; avoid body, html, and :root selectors.",
      "items": {
        "type": "object",
        "required": ["search"],
        "properties": {
          "action": {
            "type": "string",
            "enum": ["replace", "insert_after", "insert_before", "delete"],
            "description": "Patch action: replace, insert_after, insert_before, or delete. Defaults to replace."
          },
          "search": {
            "type": "string",
            "description": "Exact current CSS substring copied from read_part include=source. Must match exactly once for exact patches. Empty string is only accepted when replace/content is a complete selector block that can be treated as css_rules."
          },
          "replace": {
            "type": "string",
            "description": "Replacement CSS for the matched search substring."
          },
          "content": {
            "type": "string",
            "description": "CSS to insert for insert_after or insert_before."
          }
        }
      }
    },
    {
      "name": "css_rules",
      "type": "array",
      "required": false,
      "in": "body",
      "description": "Selector-based CSS changes. Use entries like {selector:\".card\", set:{color:\"#111\"}}. The friendlier declarations key is also accepted as an alias for set. Selectors must be canvas-local; avoid body, html, and :root."
    }
  ],
  "output": {
    "content_type": "text/plain",
    "description": "Plain text dry-run result with validation status, applied patch counts, HTML DIFF, CSS DIFF, and NEXT STEP guidance for edit_part mode=source_patch."
  },
  "errors": {
    "400": "Unsupported mode or no patch group.",
    "422": "Exact patch failed, CSS patch failed, or section validation failed.",
    "404": "Section not found."
  },
  "auto_approve": true,
  "group": "read"
}