ToolsTab: anyOf/$ref enum not resolved; optional enum fields not clearable (appear required) #897

Inspector Version

• 0.17.2

Describe the bug

ToolsTab does not correctly handle input schema with anyOf/$ref/enum:

• anyOf=[$ref, null] (e.g., role) is not resolved, so enum is lost and UI cannot render a dropdown.
• When falling back to nested/complex rendering, ToolsTab passes a trimmed schema (type/properties/description/items only) to DynamicJsonForm, dropping anyOf/$ref/enum.
• String enum select in ToolsTab has no clear/empty option; optional fields become effectively required after selection.

To Reproduce

1. Open Inspector, Tools tab.
2. Select a tool whose input schema matches the minimal schema below (role anyOf $ref|null, is_active boolean|null).
3. Observe: role is not rendered as an enum dropdown; selecting a string enum (where present) cannot be cleared back to undefined/null.

Expected behavior

• anyOf=[$ref, null] renders as a dropdown with enum values and supports null/clearing.
• Optional enum fields can be cleared (undefined or null per schema).
• Downstream forms receive full schema (including anyOf/$ref/enum) for accurate rendering.

Screenshots

• N/A (UI shows non-dropdown for role; optional enum cannot be cleared).

Environment (please complete the following information):

• OS: e.g. macOS (darwin 24.5.0)
• Browser: e.g. Chrome xx

Additional context

• Minimal inputSchema to reproduce:

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "role": {
      "title": "Role",
      "description": "Filter by role",
      "anyOf": [
        { "$ref": "#/$defs/UserRole" },
        { "type": "null" }
      ]
    },
    "is_active": {
      "title": "Is Active",
      "description": "Filter by active status",
      "anyOf": [
        { "type": "boolean" },
        { "type": "null" }
      ]
    }
  },
  "$defs": {
    "UserRole": {
      "title": "UserRole",
      "type": "string",
      "enum": ["customer", "admin", "moderator"]
    }
  }
}

• Affected areas/files:

  • client/src/utils/schemaUtils.ts (normalizeUnionType)
  • client/src/components/ToolsTab.tsx
  • client/src/components/DynamicJsonForm.tsx

• Suggested fixes (summary):

  • Resolve $ref within normalize (from inputSchema.$defs) and preserve enum as { type: "string", enum, nullable: true }.
  • Pass full property schema to DynamicJsonForm (avoid trimming anyOf/$ref/enum).
  • Add clear/empty option to enum selects (or cleanParams before calling the tool to omit optional empties).