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   • Client code is missing or outdated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