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The baml init command creates a new BAML project with the necessary directory structure and configuration files to get you started.

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Usage

baml init [OPTIONS]

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Options

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--dest
string
default:"."
Directory where the BAML project will be initialized. Defaults to the current directory.
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--client-type
string
Type of BAML client to generate. If not specified, the command attempts to detect the project type automatically based on files in the destination directory.Available options:
  • python/pydantic - Python clients using Pydantic models
  • typescript - TypeScript clients
  • go - Native Go clients
  • ruby/sorbet - Ruby clients with Sorbet type annotations
  • rest/openapi - REST API via OpenAPI specification
  • rust - Native Rust clients
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--openapi-client-type
string
OpenAPI client generator to use when --client-type=rest/openapi.Examples: go, java, php, ruby, rust, csharpSee the full list in the OpenAPI Generator documentation.

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What It Does

When you run baml init, the command:
  1. Detects your project type - Automatically identifies whether you’re using Python, TypeScript, Go, Ruby, or another language by checking for project files like package.json, pyproject.toml, go.mod, or Gemfile
  2. Creates project structure - Sets up a baml_src/ directory containing:
    • generators.baml - Configuration for code generation
    • clients.baml - Sample LLM client configurations
    • resume.baml - Example function to get you started
  3. Configures generators - Creates generator configuration matching your detected or specified project type, with appropriate settings for output directory, version, and client mode
  4. Sets up editor extensions - Automatically detects VSCode or Cursor and attempts to install the BAML extension for syntax highlighting and language support
  5. Copies editor rules - For Cursor users, sets up .cursor/rules/baml.mdc with helpful AI prompts for working with BAML

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Project Type Detection

The command automatically detects your project type by looking for:
  • Python: uv.lock, pyproject.toml, requirements.txt, or setup.py
  • TypeScript: package.json
  • Go: go.mod
  • Ruby: Gemfile
If no project files are detected, it uses the CLI installation context (e.g., Python if installed via pip, TypeScript if installed via npm).

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Examples

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Basic initialization

Initialize in the current directory with auto-detected project type: 
baml init

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Initialize in a specific directory

baml init --dest /path/to/my/project

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Initialize for Python

baml init --client-type python/pydantic

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Initialize for TypeScript

baml init --client-type typescript

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Initialize for Go

baml init --client-type go

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Initialize with OpenAPI for Java

baml init --client-type rest/openapi --openapi-client-type java

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Output

Successful initialization creates the following structure: 
your-project/
├── baml_src/
│   ├── generators.baml    # Generator configuration
│   ├── clients.baml       # LLM client setup
│   └── resume.baml        # Example function
└── .cursor/               # (Cursor users only)
    └── rules/
        └── baml.mdc       # AI coding rules
Example output: 
✨ Created new BAML project in ./baml_src for Python clients
📚 Follow instructions at https://docs.boundaryml.com/ref/overview to get started!

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Troubleshooting

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Project already exists

Error: “Looks like you already have a BAML project at ./baml_src” Solution: The destination directory already contains a baml_src folder. Either:
  • Choose a different destination with --dest
  • Remove or rename the existing baml_src directory
  • Use the existing project instead of initializing a new one

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OpenAPI generator not found

Warning: “Failed to find openapi-generator-cli in your PATH” Solution: When using --client-type=rest/openapi, install the OpenAPI generator: 
# Using npm
npm install -g @openapitools/openapi-generator-cli

# Or use a standalone installation
# See https://github.com/OpenAPITools/openapi-generator#installation
The command will fall back to using npx @openapitools/openapi-generator-cli if available.

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Extension installation fails

Issue: BAML extension doesn’t install automatically Solution: Manually install the extension:
  1. Open VSCode or Cursor
  2. Go to Extensions (Cmd/Ctrl+Shift+X)
  3. Search for “BAML”
  4. Click Install
Or install via command line: 
# VSCode
code --install-extension boundary.baml-extension

# Cursor
cursor --install-extension boundary.baml-extension

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Go package name detection

Warning: “Failed to find go.mod file, please update the client_package_name” Solution: If initializing a Go project without an existing go.mod, manually update the client_package_name in baml_src/generators.baml after running go mod init: 
generator target {
  output_type "go"
  client_package_name "github.com/yourname/yourproject"  // Update this
  // ...
}

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Next Steps

After initialization:
  1. Set up API keys - Create a .env file with your LLM provider credentials: 
    OPENAI_API_KEY=your_key_here
ANTHROPIC_API_KEY=your_key_here
  2. Generate client code - Run code generation: 
    baml generate
  3. Explore the example - Check out baml_src/resume.baml to see how BAML functions work
  4. Start building - Create your own BAML functions or modify the example
  5. Read the docs - Visit https://docs.boundaryml.com for comprehensive guides
  • baml generate - Generate client code from BAML files
  • baml dev - Start development server with hot reload
  • baml test - Run tests for your BAML functions

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