diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f489c5d..77a28b2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -42,7 +42,7 @@ jobs:
       # TODO(yuanbohan): code coverage with pytest-cov
       - name: Test with pytest
         run: |
-          pip install pytest
+          pip install pytest langchain tiktoken
           pytest tests/
 
       - name: Lint & Format with Ruff
diff --git a/README.md b/README.md
index ca72b60..4e3ad7c 100644
--- a/README.md
+++ b/README.md
@@ -14,8 +14,6 @@ pip install --upgrade greptimeai
 
 ## Usage
 
-TODO(yuanbohan): make sure this link is correct!!
-
 To get started, create a service by registering [greptimeai][greptimeai], and get:
 
 - host
@@ -33,8 +31,9 @@ export GREPTIMEAI_TOKEN=''
 #### LangChain
 
 LangChain provides a callback system that allows you to hook into the various stages of your LLM
-application. Import GreptimeCallbackHandler, which helps to collect metrics and traces to
-GreptimeCloud.
+application.
+Assuming you're using LangChain to empower your Application, what you need to do is just initiate
+GreptimeCallbackHandler as the following:
 
 ```python
 from greptimeai.langchain.callback import GreptimeCallbackHandler
@@ -57,7 +56,7 @@ chain.run(number=2, callbacks=callbacks)
 ```
 
 This example needs to be configured with your OpenAI account's private API key which is available on
-our [developer platform][openai]. Set it as the `OPENAI_API_KEY` environment variable:
+[openai platform][openai]. Set it as the `OPENAI_API_KEY` environment variable:
 
 ```bash
 export OPENAI_API_KEY='sk-...'
@@ -65,7 +64,7 @@ export OPENAI_API_KEY='sk-...'
 
 #### OpenAI
 
-TODO
+Coming
 
 [greptimeai]: https://console.greptime.cloud/ai
 [greptimeai-cookbook]: https://github.com/GreptimeTeam/greptimeai-cookbook
diff --git a/pyproject.toml b/pyproject.toml
index 3d1700a..189705f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,16 +1,14 @@
 [project]
 name = "greptimeai"
-version = "0.1.7"
+version = "0.1.8"
 description = "Observability tool for LLM application"
 authors = [
     { name = "Greptime", email = "info@greptime.com" },
 ]
 dependencies = [
-    "langchain>=0.0.285",
     "opentelemetry-api>=1.20.0",
     "opentelemetry-sdk>=1.20.0",
     "opentelemetry-exporter-otlp-proto-http>=1.20.0",
-    "tiktoken>=0.5.1",
 ]
 keywords = [
     "greptime",
@@ -23,6 +21,9 @@ keywords = [
 readme = "README.md"
 requires-python = ">= 3.8"
 
+[project.optional-dependencies]
+openai = ["tiktoken>=0.5.1"]
+
 [build-system]
 requires = ["setuptools>=61.0"]
 build-backend = "setuptools.build_meta"
@@ -32,6 +33,8 @@ managed = true
 dev-dependencies = [
     "ruff>=0.1.3",
     "pytest>=7.4.3",
+    "langchain>=0.0.27",
+    "tiktoken>=0.5.1",
 ]
 
 [tool.rye.scripts]
diff --git a/requirements.lock b/requirements.lock
index c54b3a9..05b858e 100644
--- a/requirements.lock
+++ b/requirements.lock
@@ -7,50 +7,22 @@
 #   all-features: false
 
 -e file:.
-aiohttp==3.8.6
-aiosignal==1.3.1
-annotated-types==0.6.0
-anyio==3.7.1
-async-timeout==4.0.3
-attrs==23.1.0
 backoff==2.2.1
 certifi==2023.7.22
 charset-normalizer==3.3.1
-dataclasses-json==0.6.1
 deprecated==1.2.14
-exceptiongroup==1.1.3
-frozenlist==1.4.0
 googleapis-common-protos==1.61.0
 idna==3.4
 importlib-metadata==6.8.0
-jsonpatch==1.33
-jsonpointer==2.4
-langchain==0.0.325
-langsmith==0.0.53
-marshmallow==3.20.1
-multidict==6.0.4
-mypy-extensions==1.0.0
-numpy==1.24.4
 opentelemetry-api==1.20.0
 opentelemetry-exporter-otlp-proto-common==1.20.0
 opentelemetry-exporter-otlp-proto-http==1.20.0
 opentelemetry-proto==1.20.0
 opentelemetry-sdk==1.20.0
 opentelemetry-semantic-conventions==0.41b0
-packaging==23.2
 protobuf==4.24.4
-pydantic==2.4.2
-pydantic-core==2.10.1
-pyyaml==6.0.1
-regex==2023.10.3
 requests==2.31.0
-sniffio==1.3.0
-sqlalchemy==2.0.22
-tenacity==8.2.3
-tiktoken==0.5.1
 typing-extensions==4.8.0
-typing-inspect==0.9.0
 urllib3==2.0.7
 wrapt==1.15.0
-yarl==1.9.2
 zipp==3.17.0