Brummer MCP Server

# Brummer Hub Test Coverage Summary ## Executive Summary As an experienced QA engineer, I've conducted a comprehensive analysis of the Brummer codebase, focusing on the MCP hub functionality. This report identifies critical gaps between requirements, implementation, and test coverage. ## Test Coverage Analysis ### ✅ Well-Tested Areas 1. **Core Components** - Configuration loading (`internal/config`) - Log storage and parsing (`internal/logs`) - Process management (`internal/process`) - Event system (`pkg/events`) - Basic TUI functionality (`internal/tui`) 2. **MCP Components** - Hub client HTTP operations - Tool name compliance - Basic connection management - Instance discovery ### ❌ Critical Gaps Identified #### 1. **Health Monitor Recovery Logic** (HIGH PRIORITY) - **Issue**: Health monitor only checks `StateActive` instances, preventing recovery detection - **Impact**: Once unhealthy, instances cannot recover automatically - **Code Location**: `health_monitor.go:116` - **Fix Required**: Check instances in `StateRetrying` state for recovery #### 2. **Streaming Not Implemented** (MEDIUM PRIORITY) - **Issue**: Tools like `hub_logs_stream` return static JSON instead of streaming - **Impact**: Real-time log monitoring doesn't work as expected - **User Expectation**: Continuous log updates with `follow=true` - **Current Behavior**: Single JSON response #### 3. **Dead Instance Handling** (MEDIUM PRIORITY) - **Issue**: Dead instances are hidden from `ListInstances()` but not cleaned up - **Impact**: Memory leak potential, confusing state management - **Fix Required**: Proper cleanup mechanism or resurrection path #### 4. **Missing Resource/Prompt Proxying** (LOW PRIORITY) - **Issue**: Only tools are proxied, not resources or prompts - **Impact**: Incomplete MCP protocol implementation - **Files**: `resource_proxy.go`, `prompt_proxy.go` have no tests ## Test Results Summary ### Tests Created 1. **hub_client_test.go** (441 lines) - HTTP client initialization - Error propagation - Concurrent requests - Reconnection scenarios 2. **hub_tools_test.go** (460 lines) - Tool registration - Mock instance integration - Concurrent tool calls - Lifecycle testing 3. **connection_manager_edge_cases_test.go** (615 lines) - State transition validation - Rapid connect/disconnect - Session management - Memory leak prevention 4. **health_monitor_integration_test.go** (468 lines) - Failure detection - State transitions - Intermittent availability ### Key Findings #### 1. **Intermittent Availability Handling** The hub successfully maintains instance registry during intermittent failures, which aligns with the primary use case. However: - Recovery detection needs improvement - State transition logic is incomplete - No backoff strategy for retries #### 2. **Realistic Usage Patterns** Tests confirm the system handles 1-5 instances well, which matches the expected use case. Performance issues would only appear with 20+ instances. #### 3. **Race Conditions** No critical race conditions found in normal usage patterns. The channel-based architecture prevents most concurrency issues. ## Gaps Between Requirements and Implementation ### 1. **Timing Statistics** - **Requirement**: Track time in each state - **Implementation**: Basic tracking exists but no aggregation - **Gap**: Users can't see how long an instance has been unhealthy ### 2. **Session Management** - **Requirement**: Track active sessions per instance - **Implementation**: Session map exists but not exposed - **Gap**: No session count in `instances_list` output ### 3. **Error Context** - **Requirement**: Provide actionable error messages - **Implementation**: Generic error strings - **Gap**: Users don't know why connections fail ## Recommendations ### Priority 1: Fix Health Monitor Recovery ```go // In checkAllInstances(), also check retrying instances if info.State != StateActive && info.State != StateRetrying { continue } ``` ### Priority 2: Implement Streaming - Use Server-Sent Events for `logs_stream` and `telemetry_events` - Add proper context cancellation - Implement buffering for slow clients ### Priority 3: Improve State Management - Add explicit state machine with allowed transitions - Implement resurrection path for dead instances - Add connection retry backoff ### Priority 4: Enhanced Diagnostics - Add connection failure reasons to instance info - Track and expose session counts - Include last error in `instances_list` output ## Test Execution Commands ```bash # Run all hub tests go test -v ./internal/mcp/ -timeout 60s # Run specific test suites go test -v -run TestHubClient ./internal/mcp/ go test -v -run TestHubTools ./internal/mcp/ go test -v -run "TestState|TestSession" ./internal/mcp/ go test -v -run TestHealthMonitor ./internal/mcp/ # Run with race detection go test -race ./internal/mcp/ # Run with coverage go test -cover ./internal/mcp/ ``` ## Conclusion The Brummer hub implementation successfully addresses its primary goal: providing a stable endpoint for MCP clients when instances are intermittently available. However, several implementation gaps prevent it from being production-ready: 1. **Health recovery is broken** - Critical fix needed 2. **No streaming support** - Feature incomplete 3. **State management needs refinement** - Reliability issue 4. **Missing observability** - Debugging is difficult The test suite is comprehensive for the implemented features but reveals these gaps clearly. The architecture is sound, but the implementation needs the fixes detailed above before production use.