instrument_baml()

Signature

def instrument_baml(baml_client: Any) -> Any

Overview

Unlike Anthropic, OpenAI, LangChain, and Gemini — which are auto-instrumented automatically — BAML clients are code-generated per project and cannot be monkey-patched. You must explicitly wrap the client with instrument_baml().

If you use BAML without calling instrument_baml(), calls will not be traced. There is no error — they simply won’t appear in traces.

Parameters

Any

required

The BAML client instance to wrap. Typically imported as b from baml_client.

Returns

A proxy-wrapped client with tracing enabled. Assign the result back to your client variable.

Example

from baml_client import b
from rdk import observe, instrument_baml

# Required: wrap the BAML client before use
b = instrument_baml(b)

@observe(name="extract-entities")
async def process(text: str):
    return await b.ExtractEntities(text)  # Auto-traced!

How It Works

instrument_baml() wraps the BAML client in a proxy that intercepts method calls. When a BAML function is called:

The proxy detects the active trace (from @observe or trace())
A span is created with the function name and arguments
The real BAML function executes normally
The span is completed with the structured result and token usage

What Gets Captured

Field	Description
`type`	`LLM`
`name`	BAML function name (e.g., `baml.ClassifyInquiry`)
`input.args`	Function arguments
`output.result`	Structured result
`token_usage`	Token counts
`metadata.provider`	`"baml"`

Core

Synthetic Worlds

Utilities

PII Redaction

Models

Signature

Overview

Parameters

Returns

Example

How It Works

What Gets Captured

See Also

​Signature

​Overview

​Parameters

​Returns

​Example

​How It Works

​What Gets Captured

​See Also

Signature

Overview

Parameters

Returns

Example

How It Works

What Gets Captured

See Also