# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

Stata-MCP is an MCP (Model Context Protocol) server that enables LLMs to execute Stata commands and perform statistical/regression analysis. It supports:
- **MCP server mode**: FastMCP-based server exposing Stata tools to LLMs
- **CLI tools**: Direct command-line access to all Stata capabilities

License: **AGPL-3.0** | Python: **>=3.11**

## Common Development Commands

### Environment Setup
```bash
# Install dependencies and create virtual environment
uv sync

# Install the package in development mode
uv pip install -e .

# Verify installation
stata-mcp --version

# Run diagnostics to check system health
stata-mcp doctor

# NOTE: --usable is deprecated since v1.14.3, use "stata-mcp doctor" instead
```

### Running Tests
```bash
# Run all tests
pytest

# Run specific test file
pytest tests/test_server_parser.py
pytest tests/test_server_registration.py
```

### Building and Distribution
```bash
# Build source distribution and wheels
uv build

# Build specific formats
uv build --sdist    # Source distribution only
uv build --wheel    # Wheel only

# Specify output directory
uv build --out-dir dist/
```

### Running the Application

#### MCP Server Mode (default)
```bash
# Start MCP server with stdio transport (default)
stata-mcp

# Start with specific transport
stata-mcp -t http    # HTTP transport
stata-mcp -t sse     # SSE transport

# Start with tool profile selection
stata-mcp server                     # All tools, stdio (same as bare command)
stata-mcp server --core              # Core tools only (stata_do, get_data_info, help)
stata-mcp server --all -t http       # All tools, HTTP transport
stata-mcp server --core -t http      # Core tools, HTTP transport
```

#### Utility Commands
```bash
# Run diagnostics to check system health (replaces deprecated --usable)
stata-mcp doctor
stata-mcp doctor --verbose          # Detailed output
stata-mcp doctor --json             # JSON output
stata-mcp doctor --check stata      # Run specific check(s)
stata-mcp doctor --dry-run          # Preview cleanup actions without deleting files

# Verify MCP client configuration (read-only)
stata-mcp verify                    # Error: must specify -c or -f
stata-mcp verify -c claude          # Check a supported client
stata-mcp verify -f ~/.cursor/mcp.json
stata-mcp verify -f ~/.codex/config.toml --index mcp_servers

# Check version
stata-mcp --version
```

### Development with uvx
```bash
# Run without local installation
uvx stata-mcp --version
uvx stata-mcp doctor
```

## Source Layout

```
src/stata_mcp/
├── __init__.py              # Lazy-loading exports: stata_mcp (server), main (CLI)
├── mcp_servers.py           # FastMCP server with _TOOL_REGISTRY and register_tools()
├── config.py                # Unified config management (TOML + env vars)
├── api/                     # Tool API wrappers (thin layer over core logic)
│   ├── _runtime.py          # RuntimeContext dataclass for execution contexts
│   ├── stata_do.py          # stata_do() with security guard + RAM monitor
│   ├── get_data_info.py     # Data file analysis dispatcher
│   ├── read_log.py          # Log file reader (text and SMCL formats)
│   ├── stata_help.py        # Stata command documentation
│   ├── ado_install.py       # Package installer (SSC/GitHub/net)
│   └── write_dofile.py      # Do-file creator (deprecated)
├── cli/                     # Command-line interface
│   ├── _cli.py              # Entry point and subcommand routing
│   ├── _parsers.py          # Argument parser definitions for all subcommands
│   └── _handlers.py         # Command handler implementations
├── stata/                   # Stata integration layer
│   ├── stata_finder/        # Platform-specific Stata executable locator
│   │   ├── finder.py        # Factory dispatcher
│   │   ├── base.py          # Abstract base
│   │   ├── macos.py         # macOS implementation
│   │   ├── windows.py       # Windows implementation
│   │   └── linux.py         # Linux implementation
│   ├── stata_controller/    # Interactive pexpect-based Stata session
│   ├── stata_do/            # Batch do-file execution with subprocess
│   └── builtin_tools/
│       ├── ado_install/     # SSC_Install, NET_Install, GITHUB_Install
│       ├── help/            # StataHelp with disk caching
│       └── stata_log/       # Log readers: text and SMCL formats
├── data_info/               # Data file analysis handlers
│   ├── base.py              # DataInfoBase ABC, Series dataclasses
│   ├── csv.py               # CSV handler
│   ├── dta.py               # Stata .dta handler
│   ├── xlsx.py              # Excel handler
│   └── spss.py              # SPSS .sav handler
├── guard/                   # Security validation
│   ├── validator.py         # GuardValidator, RiskItem, SecurityReport
│   └── blacklist.py         # DANGEROUS_COMMANDS, DANGEROUS_PATTERNS
├── monitor/                 # Process monitoring
│   ├── base.py              # MonitorBase ABC
│   └── ram_monitor.py       # RAMMonitor (threading + psutil)
├── evaluate/                # Evaluation and scoring
│   ├── _model.py            # OpenAI client config (DEFAULT/CHAT/THINKING models)
│   ├── score_it.py          # Scoring module
│   ├── advice.py            # Advice generation
│   └── agent_runner.py      # Evaluation agent runner
├── utils/                   # Utility modules
│   ├── doctor.py            # Diagnostics: CheckStatus, DoctorReport
│   ├── update.py            # Version checking and update orchestration
│   ├── usable.py            # Legacy usability check (deprecated)
│   └── Installer/           # MCP client integration installer
└── core/
    └── types/
        └── _error.py        # Custom exceptions: StataCLINotFoundError, RAMLimitExceededError
```

## Architecture Overview

### 1. MCP Server (`src/stata_mcp/mcp_servers.py`)

FastMCP-based server. Key design points:
- Tools are **not** registered at import time — `register_tools(server, profile)` must be called explicitly
- `_TOOL_REGISTRY` dict maps tool names to metadata (description, func, profiles, flags)
- Two profiles: `core` (3 tools) and `all` (6 tools)
- Platform filters: `unix_only=True` for `help` tool
- Deprecated flag: `write_dofile` is flagged deprecated
- Profile lock-in: switching profiles after registration raises an error

### 2. API Layer (`src/stata_mcp/api/`)

Thin wrappers that compose core logic. Each function:
- Accepts a `RuntimeContext` (config, paths, stata CLI info)
- Validates inputs, runs security guard if enabled, invokes core logic
- Returns structured results ready for MCP tool responses

### 3. Stata Integration (`src/stata_mcp/stata/`)

| Component | Description |
|-----------|-------------|
| `StataFinder` | Locates Stata executable per platform |
| `StataController` | pexpect-based interactive Stata sessions |
| `StataDo` | Subprocess batch do-file execution with monitor hooks |
| `StataHelp` | Help text retrieval with optional disk caching |
| `SSC_Install` / `NET_Install` / `GITHUB_Install` | Package installation from different sources |

### 4. Data Processing (`src/stata_mcp/data_info/`)

`get_data_handler()` auto-detects format and returns the appropriate handler:

| Handler | Formats |
|---------|---------|
| `CsvDataInfo` | `.csv` |
| `DtaDataInfo` | `.dta` (Stata) |
| `ExcelDataInfo` | `.xlsx`, `.xls` |
| `SpssDataInfo` | `.sav` (SPSS) |

All handlers extend `DataInfoBase` and return `Series` dataclasses with typed numeric and string statistics.

### 5. CLI Interface (`src/stata_mcp/cli/`)

Modular architecture:
- `_parsers.py` defines argument parsers for: `server`, `doctor`, `tool`, `config`, `install`, `update`, `verify`
- `_handlers.py` implements the corresponding handler functions
- `_cli.py` routes subcommands and serves as the package entry point

#### Verify Subcommand

`stata-mcp verify` is a read-only check that confirms whether `stata-mcp` is installed in a target MCP client or config file.

| Option | Short | Description |
|--------|-------|-------------|
| `--client` | `-c` | Target client key (e.g. `claude`, `cursor`, `codex`) |
| `--file` | `-f` | Path to a custom JSON/TOML config file |
| `--index` | | Dot-separated nested key path, used with `-f` (e.g. `mcp.servers`) |
| `--key` | | Entry key inside the target dict (default: `stata-mcp`) |

`-c` takes precedence over `-f` when both are provided.

### 6. Configuration System (`src/stata_mcp/config.py`)

Priority (highest to lowest): **environment variables > config file > defaults**

`Config` class uses `@cached_property` for lazy directory creation. `StataMcpFolder` helper manages the working directory structure.

Config file location: `~/.statamcp/config.toml`. See `src/stata_mcp/config.py` for the configuration schema.

### data_info Configuration

The `[data_info]` section controls the behavior of `get_data_info` and the `stata-mcp tool data-info` CLI command.

For `string_keep_number`, `decimal_places`, and `hash_length`, values are read with priority: explicit argument > environment variable > config file > default.

`metrics` is read from the config file only and does not support environment variables or explicit arguments.

| Key | Default | Description |
|-----|---------|-------------|
| `metrics` | `["obs", "mean", "stderr", "min", "max"]` | Numeric statistics to include in summaries. Allowed additions: `q1`, `q3`, `skewness`, `kurtosis`. |
| `string_keep_number` | `10` | Maximum number of unique string values to list for string variables. |
| `decimal_places` | `3` | Number of decimal places for numeric statistics. |
| `hash_length` | `12` | Length of the hash suffix used in cache file names. |

Example `~/.statamcp/config.toml`:
```toml
[data_info]
metrics = ["obs", "mean", "stderr", "min", "max", "q1", "q3", "skewness", "kurtosis"]
string_keep_number = 10
decimal_places = 3
hash_length = 12
```

Equivalent environment variables:
- `STATA_MCP_DATA_INFO_STRING_KEEP_NUMBER`
- `STATA_MCP_DATA_INFO_DECIMAL_PLACES`
- `STATA_MCP_DATA_INFO_HASH_LENGTH`

### 7. Security Guard (`src/stata_mcp/guard/`)

`GuardValidator` scans do-files before execution:
- `DANGEROUS_COMMANDS`: Prohibited Stata commands including minimum abbreviations (e.g., `shell`/`sh`, `erase`/`era`)
- `DANGEROUS_PATTERNS`: Regex patterns for dangerous constructs (e.g., `! del`, `! rm`)
- **Macro expansion detection**: Tracks `local` definitions that contain dangerous commands and flags later usages of `` `name' ``
- Returns `SecurityReport` with a list of `RiskItem` objects
- Configurable via `IS_GUARD` setting (default: `true`)
- When disabled, a `[SECURITY]` warning is logged at startup/execution

### 8. Monitoring System (`src/stata_mcp/monitor/`)

`RAMMonitor` runs in a background thread:
- Polls Stata process RAM usage via `psutil`
- Terminates process when usage exceeds `MAX_RAM_MB`
- Raises `RAMLimitExceededError` with usage details
- Configurable via `IS_MONITOR` and `MAX_RAM_MB` settings

### MCP Tools Provided

Tools are registered based on profile selection (`--core` / `--all` / `--unsafe`):

| Profile | Tool | Notes |
|---------|------|-------|
| core, all, unsafe | `stata_do` | Execute Stata do-files; package-management commands are always blocked |
| core, all, unsafe | `get_data_info` | Analyze data files (CSV/TSV/PSV, DTA, XLSX/XLS, SPSS SAV/ZSAV) |
| core, all, unsafe | `help` | Stata command documentation (Unix only) |
| all, unsafe | `read_log` | Read log files; supports `lines` param and `full`/`core`/`dict` formats |
| unsafe | `ado_package_install` | Install approved packages; GitHub repositories require an allowlist |
| all, unsafe | `write_dofile` | Create do-files (deprecated) |

## Testing

Tests live in `tests/` and use **pytest**. The test suite uses `monkeypatch` and stub implementations to isolate modules from heavy dependencies (FastMCP, pexpect, etc.).

| File | What it tests |
|------|--------------|
| `test_server_parser.py` | CLI argument parsing: transport flags, profile defaults, mutual exclusion |
| `test_server_registration.py` | `register_tools()`: core/all profile filtering, platform/deprecated filters, profile lock-in |
| `test_stata_do_boundary.py` | Dofile directory boundary validation: whitelist enforcement, symlinks, path traversal |
| `test_guard_validator.py` | Guard security: abbreviation blocking, macro expansion bypass detection |

Pattern for adding tests:
- Stub out external dependencies with `monkeypatch.setitem(sys.modules, ...)`
- Import the module under test after patching via `importlib.import_module()`
- Use a dummy `FastMCP`-like server object to assert which tools get registered

## Key Dependencies

| Package | Purpose |
|---------|---------|
| `mcp[cli]>=1.23.0` | MCP protocol and FastMCP server |
| `pandas>=3.0.0,<4.0.0` | Data processing (lazy-loaded) |
| `pexpect>=4.9.0` | Interactive Stata sessions |
| `openai>=1.109.1` | LLM API client |
| `psutil>=6.0.0` | RAM monitoring |
| `pyreadstat>=1.2.0` | SPSS file reading |
| `openpyxl>=3.1.5` | Excel file reading |
| `tomli-w>=1.2.0` | TOML config writing |
| `pathvalidate>=3.3.1` | Path validation |

## Git Commit Standards

This project follows the [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/) specification. For detailed guidelines, see [CONTRIBUTING.md](CONTRIBUTING.md).

**Key points:**
- Format: `<type>[optional scope]: <description>`
- Common types: `feat`, `fix`, `docs`, `style`, `refactor`, `test`, `chore`, `perf`, `ci`, `build`, `revert`
- Subject under 50 characters, imperative mood, lowercase
- Reference issues with `Closes #` or `Fixes #`
- **No co-author information in commits**
- Breaking changes: use `!` after type/scope or `BREAKING CHANGE:` footer

**Commit message must be written by a SubAgent.** Do not write commit messages from memory or imagination. Instead, spawn a `commit-commands:commit` agent, provide the first line if specified by the user, and let the agent inspect `git diff --staged` to write the detailed body based solely on the actual changes.

**Examples:**
```
feat: add spss data handler
fix(api): resolve null response in get_data_info
docs: update cli reference for server profiles
perf: lazy-load pandas at import time
```

## Branch Protection Policy

**All changes MUST be submitted via Pull Request.** Direct commits to `master` are NOT allowed.

### Branch Naming

- Feature: `feat/feature-name` or `dev/1.x.y`
- Fix: `fix/bug-name`
- Docs: `docs/doc-name`

### Standard Workflow

1. **Create branch** from the target development branch (e.g., `dev/1.x.y`):
   ```bash
   git checkout dev/1.x.y
   git checkout -b feat/feature-name
   ```
2. **Lint code**: run pre-commit hooks
3. **Stage files**: `git add <files>`
4. **Review changes**: `git diff --staged`
5. **Commit**: `git commit -m "type: description"`
6. **Push branch**: `git push -u origin feat/feature-name`
7. **Create PR** targeting the development branch (e.g., `dev/1.x.y`) via GitHub

### Keeping Dev Branches in Sync

When `master` receives updates, merge them into the development branch to reduce future conflicts:

```bash
git checkout dev/1.x.y
git merge origin/master
```

## Code Conventions

- All Python functions must have **type annotations** and **English docstrings**
- Use descriptive variable names
- Maintain proper code indentation (4 spaces)
- Heavy dependencies (`pandas`, `numpy`, `requests`) must be **lazy-loaded** at function call time, not at module import
- New data format handlers go in `src/stata_mcp/data_info/` and must register in the `DATA_INFO_REGISTRY`
- New MCP tools go in `src/stata_mcp/api/` and must be added to `_TOOL_REGISTRY` in `mcp_servers.py`
- Security-sensitive code paths must go through `GuardValidator` before execution
- The project requires a valid Stata license to run Stata commands

## Important Notes

- The `help` tool is Unix-only; it is filtered out on Windows during `register_tools()`
- `write_dofile` is deprecated — do not extend or rely on it for new features
- `--usable` CLI flag is deprecated since v1.14.3; use `stata-mcp doctor` instead