Demo auto-instrumentation capabilities

[delner]

Overview

I took some time to explore what's possible to automatically instrument with Ruby.

Here are four new ways to instrument applications with LLM libraries, from most automatic to most controlled:

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Zero Code - CLI wrapper instruments any Ruby app without code changes

Best for: Instrumenting any Ruby application without modifying its code. Requires the braintrust Ruby gem to already be installed in the bundle via Gemfile or on the system.

braintrust exec -- ruby app.rb
braintrust exec --only openai -- rails server

Zero Config - Just require (works with Bundler/Rails)

Best for: Instrumenting specific Ruby applications with smart defaults and maximum compatibility.

# In Gemfile
gem "braintrust", require: "braintrust/contrib/auto_instrument"

Single Line - Auto-instruments on init (new default behavior):

Best for: Controlling when and what instrumentation is activated.

require "braintrust"
Braintrust.init  # All available integrations instrumented automatically

# Or with filtering:
Braintrust.init(auto_instrument: { only: [:openai] })
Braintrust.init(auto_instrument: false)  # Opt-out

Explicit - Direct control over when instrumentation is applied:

Best for: Fine-control over when and which parts of an application are instrumented.

Braintrust::Contrib.auto_instrument!                    # All available
Braintrust::Contrib.auto_instrument!(only: [:openai])   # Same filtering API as `Braintrust.init`

Braintrust::Contrib.instrument!(:openai, target: client) # Per-instance manual instrumentation

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All options support environment variable overrides: BRAINTRUST_AUTO_INSTRUMENT, BRAINTRUST_INSTRUMENT_ONLY, BRAINTRUST_INSTRUMENT_EXCEPT.

[delner]

Closing this while I reformulate PRs.