### Explanation of Each File
1. **`src/hica/__init__.py`**:
   - **Purpose**: Exports the main components of the library (`Agent`, `Thread`, `ToolRegistry`, etc.) for easy import.
   - **Role**: Makes the library a Python package and provides a clean interface for users.

2. **`src/hica/logging.py`**:
   - **Purpose**: Configures `structlog` for structured logging, outputting to console and a file.
   - **Role**: Centralizes logging setup, supports configurable log levels, and adds context (e.g., thread IDs, intents).
   - **Improvements**: Replaces `print` with JSON-formatted logs, enabling better debugging and monitoring.

3. **`src/hica/models.py`**:
   - **Purpose**: Defines Pydantic models for core intents (`DoneForNow`, `ClarificationRequest`) and events.
   - **Role**: Provides type-safe data structures for agent responses and thread events.
   - **Details**: Uses enums for intents and supports extensible response models.

4. **`src/hica/core.py`**:
   - **Purpose**: Implements the `Thread` class for managing conversation state.
   - **Role**: Handles event storage and serialization (JSON or XML) for LLM context.
   - **Details**: Includes methods to check for human interaction states (`awaiting_human_response`, `awaiting_human_approval`).

5. **`src/hica/tools.py`**:
   - **Purpose**: Defines the `BaseTool` abstract class and `ToolRegistry` for tool management.
   - **Role**: Allows registration and execution of custom tools.
   - **Details**: Tools are Pydantic models with an `execute` method, supporting approval workflows.

6. **`src/hica/state.py`**:
   - **Purpose**: Implements `ThreadStore` for in-memory thread state management.
   - **Role**: Stores and retrieves threads by ID, extensible to database backends.
   - **Details**: Uses UUIDs for thread IDs, ensuring uniqueness.

7. **`src/hica/agent.py`**:
   - **Purpose**: Implements an autonomous agent for processing user queries and executing tools.
   - **Core Components**:
     - Uses `AsyncInstructor` client for LLM interactions
     - Manages conversation state via `Thread` with event tracking
     - Performs two-stage LLM processing:
       1. Tool Selection: Determines next action (tool or terminal state)
       2. Parameter Filling: Dynamically creates and uses `ToolParamsModel`
     - Executes tools through `ToolRegistry`
   - **Event Types**:
     - `user_input`: Initial user query
     - `llm_prompt`: LLM interaction prompts
     - `llm_response`: LLM decisions and responses
     - `tool_call`: Tool execution requests
     - `tool_response`: Tool execution results
   - **Features**:
     - Comprehensive event logging
     - Metadata support (userid, role)
     - Dynamic tool parameter handling
     - Terminal state management (done, clarification)

8. **`src/hica/server.py`**:
   - **Purpose**: Creates a FastAPI application with endpoints for thread management.
   - **Role**: Exposes agent functionality via HTTP (`/thread`, `/thread/{id}`, `/thread/{id}/response`).
   - **Details**: Handles human responses and approvals, logs requests and responses.

9. **`src/hica/cli.py`**:
   - **Purpose**: Provides a CLI interface for running the agent.
   - **Role**: Processes command-line inputs, supports interactive clarification requests.
   - **Details**: Integrates with `Agent` and `ThreadStore`, logs CLI interactions.

10. **`src/example/calculator_tools.py`**:
    - **Purpose**: Example implementation of calculator tools (`AddTool`, `SubtractTool`, etc.).
    - **Role**: Demonstrates how to create and register custom tools.
    - **Details**: Includes logging for tool execution, supports approval for `DivideTool`.

11. **`src/example/main.py`**:
    - **Purpose**: Entry point for running the example calculator agent.
    - **Role**: Configures the agent and runs either the CLI or server.
    - **Details**: Shows how to integrate the library with custom tools and response models.

12. **`tests/test_agent.py`**:
    - **Purpose**: Unit tests for agent functionality.
    - **Role**: Verifies thread processing, tool execution, and human interaction logic.
    - **Details**: Uses `pytest-asyncio` for async tests, covers key scenarios.

13. **`tests/test_tools.py`**:
    - **Purpose**: Unit tests for tool execution.
    - **Role**: Ensures tools produce correct results and handle edge cases.
    - **Details**: Tests calculator tools from the example.

14. **`pyproject.toml`**:
    - **Purpose**: Defines project metadata and dependencies.
    - **Role**: Managed by Poetry for reproducible builds.
    - **Details**: Includes `structlog` for logging and dev dependencies for testing.

15. **`.gitignore`**:
    - **Purpose**: Excludes unnecessary files from version control.
    - **Role**: Keeps the repository clean (e.g., ignores `.venv`, `logs/`).
    - **Details**: Includes standard Python and Poetry ignores.

16. **`README.md`**:
    - **Purpose**: Project documentation.
    - **Role**: Guides users on installation, usage, and extension.
    - **Details**: Includes setup instructions, usage examples, and 12-factor compliance details.

### Logging Improvements in Action
- **Configuration**: Set `hica_LOG_LEVEL=DEBUG` in `.env` for detailed logs during development.
- **Output**: Logs are JSON-formatted, e.g.:
  ```json
  {
    "event": "Next step determined",
    "intent": "add",
    "timestamp": "2025-06-15T22:43:00.123456",
    "level": "info",
    "logger": "hica"
  }
  ```