Python

Install BAML VSCode/Cursor Extension

https://marketplace.visualstudio.com/items?itemName=boundary.baml-extension

• syntax highlighting
• testing playground
• prompt previews

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{
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  "python.analysis.typeCheckingMode": "basic"
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}

Install BAML

$
pip install baml-py

Add BAML to your existing project

This will give you some starter BAML code in a baml_src directory.

$
baml-cli init

Generate the baml_client python module from .baml files

One of the files in your baml_src directory will have a generator block. The next commmand will auto-generate the baml_client directory, which will have auto-generated python code to call your BAML functions.

Any types defined in .baml files will be converted into Pydantic models in the baml_client directory.

$
baml-cli generate

See What is baml_client to learn more about how this works.

Use a BAML function in Python!

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from baml_client.sync_client import b
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from baml_client.types import Resume
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def example(raw_resume: str) -> Resume: 
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  # BAML's internal parser guarantees ExtractResume
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  # to be always return a Resume type
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  response = b.ExtractResume(raw_resume)
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  return response
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def example_stream(raw_resume: str) -> Resume:
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  stream = b.stream.ExtractResume(raw_resume)
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  for msg in stream:
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    print(msg) # This will be a PartialResume type
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  # This will be a Resume type
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  final = stream.get_final_response()
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  return final

Setup the autoreload extension

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%load_ext autoreload
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%autoreload 2

This will make sure to reload imports, such as baml_client’s “b” object before every cell runs.

Import baml_client module in your notebook

Note it’s different from how we import in python.

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# Assuming your baml_client is inside a dir called app/
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import app.baml_client as client # you can name this "llm" or "baml" or whatever you want

Usually we import things as from baml_client import b, and we can call our functions using b, but the %autoreload notebook extension does not work well with from...import statements.

Call BAML functions using the module name as a prefix

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raw_resume = "Here's some resume text"
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client.b.ExtractResume(raw_resume)

Now your changes in .baml files are reflected in your notebook automatically, without needing to restart the Jupyter kernel.