BAML Code Generator

When to Use This Skill

Automatically invoke this skill when:

• •User modifies any .baml file
• •User creates new BAML functions or types
• •User asks to update generated code
• •After scaffolding new BAML components
• •User mentions BAML client is out of sync

Examples That Trigger This Skill

• •"I just updated the BAML function"
• •"The type definitions changed"
• •"Generate the client code"
• •"Update the BAML client"
• •After creating function: "Now make it usable in Python/TypeScript"

How to Use

1. •

   Detect BAML project:

   • •Look for baml_src/ directory
   • •Verify BAML configuration exists
   • •Check for modified .baml files
2. •

   Determine if generation needed:

   • •Files were just modified
   • •User explicitly requests generation
   • •Client code is missing or outdated
3. •

   Run code generation:

   • •Execute baml generate command
   • •Capture output and any errors
   • •Report success or failure
4. •

   Verify generated code:

   • •Check baml_client/ directory
   • •Confirm files were created/updated
   • •Show what was generated
5. •

   Provide usage guidance:

   • •Show import statements for target language
   • •Provide code example using generated client
   • •Mention next steps (testing, integration)

Generation Process

Standard Generation

baml generate

This command:

• •Reads all .baml files in baml_src/
• •Generates typed client code
• •Outputs to baml_client/ directory
• •Creates language-specific modules

Watch Mode (Development)

For active development, suggest watch mode:

baml generate --watch

Benefits:

• •Automatically regenerates on file changes
• •Fast feedback during development
• •No manual generation needed

Language-Specific Output

Generated structure varies by language:

Python:

baml_client/
├── __init__.py
├── client.py
├── types.py
└── functions/
    ├── extract_receipt.py
    └── ...

TypeScript:

baml_client/
├── index.ts
├── client.ts
├── types.ts
└── functions/
    ├── extractReceipt.ts
    └── ...

After Generation

Python Usage Example

from baml_client import b

# Async call
result = await b.ExtractReceipt(image="path/to/receipt.jpg")
print(f"Vendor: {result.vendor}")
print(f"Total: ${result.total}")

# Streaming
async for partial in b.stream.SummarizeText(text=long_text):
    print(partial)

TypeScript Usage Example

import { b } from './baml_client';

// Async call
const result = await b.ExtractReceipt({ image: "path/to/receipt.jpg" });
console.log(`Vendor: ${result.vendor}`);
console.log(`Total: $${result.total}`);

// Streaming
const stream = b.stream.SummarizeText({ text: longText });
for await (const partial of stream) {
  console.log(partial);
}

Error Handling

Common Errors

"No BAML files found":

• •Check baml_src/ exists and contains .baml files
• •Verify working directory is project root

"Parse error in X.baml":

• •Read error message for line number
• •Check syntax (missing braces, typos, etc.)
• •Offer to fix syntax errors

"Client already exists":

• •Name conflict in client definitions
• •Check clients.baml for duplicate names

"Invalid type reference":

• •Type used in function doesn't exist
• •Check type definitions and imports

Recovery

If generation fails:

1. •Show error message to user
2. •Identify problematic file and line
3. •Suggest fix or offer to correct
4. •Re-run generation after fix

Integration with Workflows

After Creating Function

User: [creates new BAML function]
Claude: [Uses baml-scaffolder skill]
Claude: [Automatically uses baml-generator skill]
Result: Function ready to use in code

After Editing Types

User: [modifies class definition]
Claude: [Detects .baml file change]
Claude: [Uses baml-generator skill]
Result: Updated types in generated code

Best Practices

1. •Always regenerate after changes: Don't let generated code get stale
2. •Use watch mode in development: Fastest workflow
3. •Commit baml_src/, gitignore baml_client/: Source vs generated
4. •Verify generation success: Check for errors before continuing
5. •Show usage examples: Help user understand how to use generated code

Automation

This skill enables autonomous workflow:

1. •User describes AI functionality
2. •baml-scaffolder creates BAML definitions
3. •baml-generator creates usable client code (THIS SKILL)
4. •User can immediately use in their application

No manual steps needed - Claude handles the full pipeline.

Notes

• •Generated code is fully typed - leverage IDE autocomplete
• •Generation is fast (< 1 second typically)
• •Each language gets idiomatic code (Pythonic in Python, TypeScript patterns in TS)
• •Streaming support is automatically included
• •Error handling and retry logic built into generated client