# Agent State Machine Diagram

```mermaid
stateDiagram-v2
    [*] --> StateReady
    
    StateReady --> StateWaitingForUserInput
    
    StateWaitingForUserInput --> StateSendingToLLM
    StateWaitingForUserInput --> StateError
    
    StateSendingToLLM --> StateProcessingLLMResponse
    StateSendingToLLM --> StateError
    
    StateProcessingLLMResponse --> StateEndOfTurn
    StateProcessingLLMResponse --> StateToolUseRequested
    StateProcessingLLMResponse --> StateError
    
    StateEndOfTurn --> StateWaitingForUserInput
    
    StateToolUseRequested --> StateCheckingForCancellation
    
    StateCheckingForCancellation --> StateRunningTool
    StateCheckingForCancellation --> StateCancelled
    
    StateRunningTool --> StateCheckingGitCommits
    StateRunningTool --> StateError
    
    StateCheckingGitCommits --> StateRunningAutoformatters
    StateCheckingGitCommits --> StateCheckingBudget
    
    StateRunningAutoformatters --> StateCheckingBudget
    
    StateCheckingBudget --> StateGatheringAdditionalMessages
    StateCheckingBudget --> StateBudgetExceeded
    
    StateGatheringAdditionalMessages --> StateSendingToolResults
    StateGatheringAdditionalMessages --> StateError
    
    StateSendingToolResults --> StateProcessingLLMResponse
    StateSendingToolResults --> StateError
    
    StateError --> StateWaitingForUserInput
    StateCancelled --> StateWaitingForUserInput
    StateBudgetExceeded --> StateWaitingForUserInput
```

## State Descriptions

| State | Description |
|-------|-------------|
| StateReady | Initial state when the agent is initialized and ready to operate |
| StateWaitingForUserInput | Agent is waiting for a user message to start a turn |
| StateSendingToLLM | Agent is sending message(s) to the LLM |
| StateProcessingLLMResponse | Agent is processing a response from the LLM |
| StateEndOfTurn | Processing completed without tool use, turn ends |
| StateToolUseRequested | LLM has requested to use a tool |
| StateCheckingForCancellation | Agent checks if user requested cancellation |
| StateRunningTool | Agent is executing the requested tool |
| StateCheckingGitCommits | Agent checks for new git commits after tool execution |
| StateRunningAutoformatters | Agent runs code formatters on new commits |
| StateCheckingBudget | Agent verifies if budget limits are exceeded |
| StateGatheringAdditionalMessages | Agent collects user messages that arrived during tool execution |
| StateSendingToolResults | Agent sends tool results back to the LLM |
| StateCancelled | Operation was cancelled by the user |
| StateBudgetExceeded | Budget limit was reached |
| StateError | An error occurred during processing |

## Implementation Details

This state machine is implemented in `statemachine.go` and follows the State pattern design. Key features include:

1. Explicit state enumeration for all possible states
2. Validation of state transitions
3. History tracking for debugging
4. Event recording for each transition
5. Timing information for performance analysis
6. Error state detection

The `AgentWithStateMachine` in `statemachine_example.go` demonstrates how this state machine could be integrated with the existing Agent implementation.