chore: Deprecate old langchain package (#193)

Author: AbhiPrasad

integrations/langchain-py/README.md

@@ -1,9 +1,36 @@
-# braintrust-langchain
+# braintrust-langchain (DEPRECATED)
 
 [![PyPI version](https://img.shields.io/pypi/v/braintrust-langchain.svg)](https://pypi.org/project/braintrust-langchain/)
 
 SDK for integrating [Braintrust](https://braintrust.dev) with [LangChain](https://langchain.com/). This package provides a callback handler to automatically log LangChain executions to Braintrust.
 
+> **This package is deprecated.** The LangChain integration is now included in the main [`braintrust`](https://pypi.org/project/braintrust/) package.
+
+## Migration
+
+1. Remove `braintrust-langchain` from your dependencies
+2. Install or upgrade `braintrust`:
+   ```bash
+   pip install --upgrade braintrust
+   ```
+3. Update your imports:
+   ```python
+   # Before
+   from braintrust_langchain import BraintrustCallbackHandler, set_global_handler
+
+   # After (option 1: same explicit callback API from the main package)
+   from braintrust.integrations.langchain import BraintrustCallbackHandler, set_global_handler
+
+   # After (option 2: helper that initializes Braintrust and installs the global handler)
+   from braintrust.integrations.langchain import setup_langchain
+
+   setup_langchain(project_name="your-project-name")
+   ```
+
+The callback API is the same - no code changes are needed beyond the package/import path.
+
+---
+
 ## Installation
 
 ```bash

integrations/langchain-py/pyproject.toml

@@ -1,18 +1,18 @@
 [project]
 name = "braintrust-langchain"
-version = "0.2.1"
-description = "Integration for LangChain and Braintrust Tracing"
+version = "0.3.0"
+description = "DEPRECATED: LangChain integration is now included in the main braintrust package. Install braintrust instead."
 readme = "README.md"
 requires-python = ">=3.10"
 dependencies = [
-    "braintrust>=0.2.1",
+    "braintrust>=0.12.0",
     "langchain>=0.3.27",
 ]
 license = "MIT"
 authors = [{ name = "Braintrust", email = "info@braintrust.dev" }]
-keywords = ["braintrust", "langchain", "llm", "tracing", "ai", "agents"]
+keywords = ["braintrust", "langchain", "llm", "tracing", "ai", "agents", "deprecated"]
 classifiers = [
-    "Development Status :: 4 - Beta",
+    "Development Status :: 7 - Inactive",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",