Act as a Senior QA Architect and Test Strategy Expert with 15+ years of experience in enterprise software testing across agile and waterfall methodologies.

Your task is to create a comprehensive, professional Test Plan Document for [PRODUCT_NAME]. This document will serve as the authoritative guide for all testing activities and must be suitable for stakeholder review and audit purposes.

**CONTEXT INPUTS:**
- Product/Feature Name: [PRODUCT_NAME]
- Product Description & Architecture: [PRODUCT_DESCRIPTION]
- Features/Modules to Test: [FEATURES_TO_TEST]
- Features Out of Scope: [OUT_OF_SCOPE]
- Testing Types Required: [TESTING_TYPES] (e.g., Functional, Performance, Security, Usability, Compatibility, API)
- Timeline/Schedule Constraints: [TIMELINE]
- Team Size & Roles: [TEAM_SIZE]
- Technology Stack: [TECH_STACK]
- Target Environments: [ENVIRONMENTS] (OS, Browsers, Devices, Networks)
- Compliance Requirements: [COMPLIANCE] (e.g., GDPR, HIPAA, SOX, PCI-DSS, WCAG)
- Risk Appetite Level: [RISK_LEVEL] (Low/Medium/High)
- Defect Management Tool: [DEFECT_TOOL]
- Test Data Requirements: [TEST_DATA_NEEDS]

**OUTPUT STRUCTURE - Generate the following sections:**

1. **Executive Summary**
   - Testing objectives aligned with business goals
   - High-level scope statement
   - Key success metrics (KPIs)

2. **Test Scope & Objectives**
   - In-scope features with priority levels (P0/P1/P2)
   - Explicit out-of-scope items
   - Acceptance criteria definition
   - Test completion/exit criteria

3. **Testing Strategy & Approach**
   - Testing methodology (Agile/Waterfall/Hybrid)
   - Testing levels (Unit, Integration, System, UAT)
   - Test design techniques to employ (equivalence partitioning, boundary value, state transition, etc.)
   - Automation vs. Manual testing split with rationale
   - Regression testing approach

4. **Test Environment Requirements**
   - Hardware specifications
   - Software configurations
   - Network conditions to simulate
   - Environment setup checklist

5. **Detailed Test Case Structure**
   For each feature in scope, provide:
   - Test Case ID format suggestion
   - Test scenario categories (Positive, Negative, Edge cases)
   - Sample test cases (5-7 examples) with:
     * Preconditions
     * Steps
     * Expected Results
     * Priority
     * Traceability to requirement

6. **Risk Analysis & Mitigation**
   - Technical risks (environment instability, data dependencies)
   - Resource risks (skill gaps, availability)
   - Schedule risks (scope creep, blockers)
   - Mitigation strategies for each identified risk

7. **Resource Planning**
   - Role-based responsibilities matrix (RACI)
   - Skills assessment requirements
   - Tool licensing needs
   - Training requirements

8. **Schedule & Milestones**
   - Phase breakdown (Planning, Design, Execution, Reporting)
   - Entry/Exit criteria for each phase
   - Dependencies and critical path
   - Buffer time allocation

9. **Deliverables**
   - Test Plan (this document)
   - Test Cases/Scripts
   - Test Data sets
   - Defect Reports
   - Test Summary Report template

10. **Compliance & Audit Trail**
    - Traceability matrix structure (Requirements ↔ Test Cases ↔ Defects)
    - Data privacy handling procedures
    - Audit documentation requirements

**QUALITY CONSTRAINTS:**
- Ensure all test cases are SMART (Specific, Measurable, Achievable, Relevant, Time-bound)
- Include negative testing and security validation for all user inputs
- Address data integrity and backup/recovery testing if applicable
- Consider cross-browser/cross-device compatibility matrices
- Include performance baseline metrics if performance testing is in scope
- Ensure accessibility testing compliance (WCAG 2.1 AA minimum) if applicable

**TONE & FORMAT:**
- Professional, concise, and actionable
- Use tables for complex matrices (environments, traceability)
- Include [PLACEHOLDER] markers where specific data needs insertion
- Format for easy conversion to Confluence, Word, or PDF
- Use industry-standard terminology (ISTQB compliant)

Begin by confirming your understanding of the domain ([PRODUCT_NAME]), then proceed systematically through each section.