Commits on Jan 25, 2026

1. refactor: Replace agent loop with event-driven state machine (#379) …

   ## Overview
   
   This PR completes the agent state machine refactoring by extracting all
   state handlers into separate, maintainable files following the **State
   Design Pattern**. This improves code organization, readability, and
   scalability.
   
   ## Problem Statement
   
   The previous implementation had all state handlers in a single 1400+
   line file (`agent_event_driven.go`), making it:
   - **Hard to navigate**: Finding specific state logic required scrolling
   through unrelated code
   - **Difficult to maintain**: Changes to one state risked affecting
   others
   - **Complex to review**: PR reviews had to parse through the entire
   event-driven agent implementation
   - **Not scalable**: Adding new states or modifying existing ones became
   increasingly difficult
   
   ## Solution
   
   Refactored the agent state machine to follow the [State Design
   Pattern](https://refactoring.guru/design-patterns/state):
   
   ### Architecture Changes
   
   **Before:**
   ```
   internal/services/
   ├── agent.go (1400+ lines - monolithic)
   ├── agent_event_driven.go
   └── tools/
   ```
   
   **After:**
   ```
   internal/agent/
   ├── agent.go (1200 lines) - core service
   ├── agent_event_driven.go (400 lines) - event coordinator
   ├── agent_state_machine.go - state transitions
   ├── agent_streaming.go - LLM streaming
   ├── agent_tools.go - tool execution
   ├── agent_utils.go - helpers
   └── states/ (12 files, ~50-100 lines each)
       ├── idle.go
       ├── checking_queue.go
       ├── streaming_llm.go
       ├── post_stream.go
       ├── evaluating_tools.go
       ├── approving_tools.go
       ├── executing_tools.go
       ├── post_tool_execution.go
       ├── completing.go
       ├── error.go
       ├── cancelled.go
       └── stopped.go
   ```
   
   ### Key Components
   
   1. **State Handler Interface** (`state_handler.go`)
      - Defines `Handle(event)` method all states must implement
      - `StateContext` provides access to agent dependencies
   
   2. **Concrete States** (`states/*.go`)
      - Each state in its own file
      - Implements the `StateHandler` interface
      - Processes events relevant to that state
   
   3. **Event-Driven Agent** (`agent_event_driven.go`)
      - Simplified to ~400 lines (from 1400+)
      - Maintains state handler registry
      - Delegates events to appropriate state handlers
   
   ## Changes Made
   
   ### Phase 1: Infrastructure
   - ✅ Created `StateHandler` interface and `StateContext` struct
   - ✅ Created `states/` package for state implementations
   
   ### Phase 2: State Extraction
   Extracted all 12 states into separate files:
   1. ✅ `idle.go` - Initial state, transitions to CheckingQueue
   2. ✅ `error.go` - Terminal state for errors
   3. ✅ `cancelled.go` - Terminal state for user cancellation
   4. ✅ `stopped.go` - Terminal state for stops
   5. ✅ `completing.go` - Finalization and cleanup
   6. ✅ `evaluating_tools.go` - Tool approval evaluation
   7. ✅ `streaming_llm.go` - LLM streaming coordination
   8. ✅ `post_stream.go` - Post-streaming transitions
   9. ✅ `executing_tools.go` - Tool execution coordination
   10. ✅ `checking_queue.go` - Queue processing and completion logic
   11. ✅ `approving_tools.go` - User approval workflow
   12. ✅ `post_tool_execution.go` - Post-tool transitions
   
   ### Phase 3: Event-Driven Agent Refactoring
   - ✅ Added state handler registry (`stateHandlers` map)
   - ✅ Implemented `registerStateHandlers()` method
   - ✅ Simplified `handleEvent()` to dispatch pattern
   - ✅ Removed all `handle*State()` methods (~1000 lines deleted)
   
   ### Phase 4: Testing & Cleanup
   - ✅ Updated tests to match new architecture
   - ✅ Fixed test expectations for improved message storage timing
   - ✅ Removed outdated comments
   - ✅ All tests passing
   - ✅ Linter clean (0 issues)
   
   ## Benefits
   
   ### Code Organization
   - **Before**: 1400+ line file with 12 state handlers
   - **After**: 12 focused files, each 30-100 lines
   - Clear separation: one state = one file
   - Easy to locate and modify state-specific logic
   
   ### Maintainability
   - Each state is isolated (LSP compliance)
   - PR reviews focus on specific state files
   - New states just add a new file + registration line
   - Reduced merge conflicts (different files)
   
   ### Testability
   - Each state tested in isolation with its own test file
   - Easy to mock `StateContext` for state-specific tests
   - Test failures clearly indicate problematic state
   
   ### Scalability
   - 12 states = 12 files × 50-100 lines (manageable)
   - Adding states doesn't increase file complexity
   - Clear pattern for new state implementations
   
   ## Design Patterns Applied
   
   1. **State Design Pattern** - Context delegates to state handlers
   2. **Single Responsibility Principle** - One file handles one state's
   events
   3. **Open/Closed Principle** - Open for extension, closed for
   modification
   4. **Dependency Inversion** - States depend on `StateContext` interface
   
   ## Testing
   
   - ✅ All unit tests passing
   - ✅ Integration tests passing
   - ✅ No race conditions (`go test -race`)
   - ✅ Code coverage maintained
   - ✅ Manual testing confirms normal operation
   
   ## Migration Impact
   
   - **Lines Removed**: ~1000 (state handlers extracted)
   - **Lines Added**: ~800 (12 new state files + infrastructure)
   - **Net Reduction**: ~200 lines
   - **Complexity Reduction**: Significant (from one 1400-line file to 12
   focused files)
   
   ## Verification
   
   ```bash
   # Build
   task build
   ✅ Success
   
   # Tests
   task test
   ✅ All tests passing (internal/agent: 1.212s)
   
   # Linter
   task lint
   ✅ 0 issues
   ```
   
   ## Breaking Changes
   
   None. This is a pure refactoring with no API or behavior changes.
   
   ## References
   
   - [State Design Pattern - Refactoring
   Guru](https://refactoring.guru/design-patterns/state)
   - [State Pattern in
   Go](https://refactoring.guru/design-patterns/state/go/example)
   - [Go Code Review
   Comments](https://github.com/golang/go/wiki/CodeReviewComments)

   

   edenreich authored Jan 25, 2026
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2. chore(release): 0.99.2 [skip ci] …

   ## [0.99.2](v0.99.1...v0.99.2) (2026-01-25)
   
   ### ♻️ Code Refactoring
   
   * Replace agent loop with event-driven state machine ([#379](#379)) ([536fdc6](536fdc6))

   

   semantic-release-bot committed Jan 25, 2026
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