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Configuring the Scaffolder MCP Backend Plugin#

This guide covers the configuration options for the Scaffolder MCP backend plugin.

Basic Configuration#

The plugin works out of the box with minimal configuration. It automatically integrates with your existing Backstage scaffolder configuration.

MCP Actions Configuration#

The plugin registers 7 MCP actions automatically:

Template Management: 1. list_software_templates 2. get_software_template_parameter_schema 3. run_software_template

Scaffolder Actions Discovery: 4. list_software_template_actions 5. get_software_template_action_details

Template Extensions Discovery: 6. list_software_template_extensions 7. get_software_template_extension_details

No additional configuration is required for basic MCP action functionality.

Authentication and Authorization#

User Authentication#

All MCP actions run on behalf of the authenticated user making the request. The plugin respects Backstage's authentication system:

# app-config.yaml
backend:
  auth:
    keys:
      - secret: ${BACKEND_SECRET}

Scaffolder Permissions#

The plugin respects existing scaffolder permissions. Configure permissions using Backstage's permission framework:

permission:
  enabled: true

Using the Community RBAC Plugin#

You can use the RBAC plugins from the Backstage community to manage scaffolder permissions:

app-config.yaml snippet 

permission:
  enabled: true
  rbac:
    policies-csv-file: /path/to/permissions.csv
    policyFileReload: true
    pluginsWithPermission:
      - scaffolder

CSV file snippet 

p, role:default/developers, scaffolder.task.read, read, allow
p, role:default/developers, scaffolder.task.create, create, allow
p, role:default/developers, scaffolder-template, read, allow
g, group:default/engineering, role:default/developers

Task Execution Configuration#

Timeout Settings#

The default timeout for template execution is 5 minutes. This is currently hardcoded but can be extended if needed.

Task Polling#

The plugin polls task status every 1 second until completion. This ensures timely updates while not overwhelming the backend.

Best Practices#

  1. Permission Management

    • Follow the principle of least privilege
    • Regularly review and update scaffolder policies
    • Use specific permissions over wildcards

  2. Security

    • Enable audit logging for scaffolder tasks
    • Implement proper error handling
    • Validate all template parameters

  3. Integration

    • Verify scaffolder plugin configuration
    • Check authentication settings
    • Monitor task execution and failures

  4. Monitoring

    • Track MCP action usage
    • Monitor task completion rates
    • Review failed task logs
    • Monitor action and extension discovery requests

Use Cases#

Template Execution#

Use the template management actions (list_software_templates, get_software_template_parameter_schema, run_software_template) for: - Automating template execution workflows - AI-assisted template selection and execution - Programmatic component creation

Template Development#

Use the discovery actions (list_software_template_actions, get_software_template_action_details, list_software_template_extensions, get_software_template_extension_details) for: - AI-assisted template development - Documentation generation for templates - Learning available scaffolder capabilities - Building template authoring tools

Advanced Configuration#

Custom Template Discovery#

The plugin discovers templates from the Backstage catalog using the scaffolder's template discovery mechanism. Ensure your templates are properly registered in the catalog.

Error Handling#

The plugin provides detailed error messages for: - Template not found errors - Invalid parameter errors - Task execution failures - Timeout errors

Review backend logs with the [Scaffolder MCP] prefix for debugging information.