AskUserQuestion tool returns null output without prompting user for input

Description

The AskUserQuestion tool returned a response with output: null but the user was never prompted to answer the questions. Neither the multiple choice options nor free text input was displayed to the user.

Expected Behavior

When AskUserQuestion is called with a questions array, the user should be prompted with an interactive UI to:

1. Select from the provided options for each question
2. Optionally provide free text via "Other" option

Actual Behavior

The tool returned immediately with output: null without displaying any prompt to the user.

Reproduction

The following input was provided to AskUserQuestion:

{
  "questions": [
    {
      "question": "What type of infrastructure component should this Terraform module manage?",
      "header": "Component",
      "multiSelect": false,
      "options": [
        {"label": "AWS Resources", "description": "EC2, S3, VPC, RDS, or other AWS services"},
        {"label": "Kubernetes", "description": "Kubernetes clusters, namespaces, or workloads"},
        {"label": "Network", "description": "VPC, subnets, security groups, load balancers"},
        {"label": "Database", "description": "RDS, DynamoDB, or other database services"}
      ]
    },
    {
      "question": "What level of complexity and configurability do you need?",
      "header": "Scope",
      "multiSelect": false,
      "options": [
        {"label": "Simple", "description": "Basic module with minimal configuration options"},
        {"label": "Standard", "description": "Moderate configurability with common use cases covered"},
        {"label": "Advanced", "description": "Highly configurable with multiple deployment patterns"}
      ]
    },
    {
      "question": "Which cloud provider should this module target?",
      "header": "Provider",
      "multiSelect": false,
      "options": [
        {"label": "AWS", "description": "Amazon Web Services"},
        {"label": "Azure", "description": "Microsoft Azure"},
        {"label": "GCP", "description": "Google Cloud Platform"},
        {"label": "Multi-cloud", "description": "Support multiple cloud providers"}
      ]
    },
    {
      "question": "What documentation and testing requirements do you have?",
      "header": "Quality",
      "multiSelect": true,
      "options": [
        {"label": "README docs", "description": "Comprehensive usage documentation"},
        {"label": "Examples", "description": "Working example configurations"},
        {"label": "Tests", "description": "Automated validation tests"},
        {"label": "CI/CD", "description": "GitHub Actions or similar pipeline"}
      ]
    }
  ]
}

Output Received

{
  "input": { ... },
  "output": null
}

Environment

• Claude Code CLI
• Tool: AskUserQuestion

Additional Context

The questions array appears valid with proper structure including:

• question: The question text
• header: Short label for the chip/tag
• multiSelect: Boolean for single/multi select
• options: Array of 2-4 options with label and description

All required fields are present per the tool schema.