SSH MCP Server

# Epic: Terminal Echo Fix with Villenele Browser Command Emulation ## Epic Intent and Business Problem **Primary Business Problem**: The SSH MCP server has developed a critical double echo regression in browser terminal display following the Command State Synchronization Epic implementation. Simultaneously, the Villenele testing framework lacks capability to emulate browser-initiated commands, preventing comprehensive test coverage of browser terminal scenarios and regression detection. **Strategic Impact**: This dual-purpose epic addresses both immediate production quality degradation and long-term testing infrastructure gaps, ensuring professional terminal experience while building robust testing capabilities for future development. ## Overall Architecture and Technology Strategy ### System Architecture Overview ``` Enhanced Villenele Testing Framework ├── PostWebSocketCommandExecutor (Enhanced) │ ├── Browser Command Router → WebSocket terminal_input messages │ ├── MCP Command Router → JSON-RPC stdin (existing) │ └── Sequential Execution Engine → Response synchronization ├── Dynamic Expected Value Construction │ ├── Runtime Command Execution → Environment-specific results │ ├── Pattern Matching Engine → Volatile output handling │ └── Cross-Platform Compatibility → Parameterized assertions └── Echo Fix Validation System ├── Before/After Comparison → Regression detection ├── Command State Sync Preservation → Epic functionality intact └── Comprehensive Test Coverage → All command scenarios validated ``` ### Technology Stack Decisions - **WebSocket Communication**: Real-time browser command emulation via terminal_input messages - **JSON-RPC 2.0**: Existing MCP client communication via stdin/stdout - **SSH2 Library**: Real SSH connections for authentic testing (no mocks per CLAUDE.md) - **Promise-based Async**: Sequential command execution with proper response waiting - **Regex Pattern Matching**: Dynamic expected value construction and echo detection - **Strategy Pattern**: Clean separation of browser vs MCP command execution paths ### Integration Points - **Command State Synchronization Epic**: Preserve all functionality while fixing echo regression - **Existing Villenele Framework**: Extend 9-story testing infrastructure without breaking changes - **SSH Connection Manager**: Modify echo handling logic with surgical precision - **Browser Terminal WebSocket**: Leverage existing terminal_input message infrastructure ## Feature Implementation Order - [x] **01_Feat_VilleneleCommandInitiatorEnhancement**: Complete framework enhancement with browser command emulation, cancellation support, and universal test suite migration - [x] **02_Feat_TerminalEchoInvestigationAndFix**: Root cause analysis and precision fix using enhanced Villenele validation - [x] **03_Feat_ComprehensiveTestCoverage**: Extensive validation scenarios for both echo fix and Command State Synchronization integration ## Success Criteria and Business Value ### Technical Success Metrics - ✅ Zero double echo in browser terminal display (professional appearance restored) - ✅ Complete Villenele browser command emulation capability (testing gap eliminated) - ✅ 100% Command State Synchronization Epic functionality preserved - ✅ Universal test suite migration to enhanced parameter structure - ✅ Cross-environment test compatibility with dynamic expected values ### Business Impact Delivered - **User Experience**: Professional terminal appearance matching native Linux terminal - **Development Velocity**: Enhanced testing capabilities preventing future regressions - **Quality Assurance**: Comprehensive test coverage for all terminal interaction scenarios - **Risk Mitigation**: Robust validation framework for terminal display changes ## Implementation Dependencies and Risk Assessment ### Critical Dependencies 1. **Command State Synchronization Epic**: Must preserve all browser command tracking, MCP gating, cancellation, and nuclear fallback functionality 2. **Existing Villenele Framework**: Must maintain compatibility with all 9 existing stories while enhancing capabilities 3. **SSH Connection Infrastructure**: Must preserve real SSH connection requirements per CLAUDE.md standards ### Risk Mitigation Strategy - **Phased Implementation**: Build testing infrastructure before touching production echo code - **Backward Compatibility**: Universal test migration with validation at each step - **Comprehensive Testing**: Use enhanced Villenele to validate echo fix before deployment - **Rollback Capability**: Each phase can be reversed independently if issues arise ## Architecture Components ### Enhanced Command Structure ```typescript // New universal format for all Villenele tests interface VilleneleCommand { initiator: 'browser' | 'mcp-client'; command: string; cancel?: boolean; // Optional: trigger cancellation after timeout waitToCancelMs?: number; // Optional: cancellation timeout (default: 10000ms) } ``` ### Dual-Channel Execution Strategy - **Browser Commands**: WebSocket terminal_input message routing with real terminal interaction - **MCP Commands**: JSON-RPC stdin routing (existing proven path) - **Sequential Coordination**: Promise-based execution ensuring proper command ordering - **Response Synchronization**: Different protocols unified under common completion interface ### Dynamic Test Validation Framework - **Runtime Expected Values**: Execute preparatory commands to gather environment-specific results - **Pattern Matching**: Handle volatile outputs (timestamps, system-specific data) with regex validation - **Cross-Platform Compatibility**: Parameterized assertions working across different user accounts and directory structures - **Regression Detection**: Before/after comparison capability for terminal behavior validation This epic transforms both immediate production quality issues and strategic testing capabilities, delivering professional terminal experience while building robust infrastructure for future development confidence.