diff --git a/Usage.md b/Usage.md
index f11b28df..19904fc4 100644
--- a/Usage.md
+++ b/Usage.md
@@ -303,6 +303,23 @@ key = ...
 
 Also review the [AiHandler](pr_agent/algo/ai_handler.py) file for instruction how to set keys for other models.
 
+#### Vertex AI
+
+To use Google's Vertex AI platform and its associated models (chat-bison/codechat-bison) set:
+
+``` 
+[config] # in configuration.toml
+model = "vertex_ai/codechat-bison"
+
+[vertexai] # in .secrets.toml
+vertex_project = "my-google-cloud-project"
+vertex_location = ""
+```
+
+Your [application default credentials](https://cloud.google.com/docs/authentication/application-default-credentials) will be used for authentication so there is no need to set explicit credentials in most environments.
+
+If you do want to set explicit credentials then you can use the `GOOGLE_APPLICATION_CREDENTIALS` environment variable set to a path to a json credentials file.
+
 ### Working with large PRs
 
 The default mode of CodiumAI is to have a single call per tool, using GPT-4, which has a token limit of 8000 tokens.
diff --git a/pr_agent/algo/__init__.py b/pr_agent/algo/__init__.py
index 5a253363..5fe82ee5 100644
--- a/pr_agent/algo/__init__.py
+++ b/pr_agent/algo/__init__.py
@@ -13,5 +13,9 @@ MAX_TOKENS = {
     'claude-2': 100000,
     'command-nightly': 4096,
     'replicate/llama-2-70b-chat:2c1608e18606fad2812020dc541930f2d0495ce32eee50074220b87300bc16e1': 4096,
-    'meta-llama/Llama-2-7b-chat-hf': 4096
+    'meta-llama/Llama-2-7b-chat-hf': 4096,
+    'vertex_ai/codechat-bison': 6144,
+    'vertex_ai/codechat-bison-32k': 32000,
+    'codechat-bison': 6144,
+    'codechat-bison-32k': 32000,
 }
diff --git a/pr_agent/algo/ai_handler.py b/pr_agent/algo/ai_handler.py
index c3989563..9a48cdc3 100644
--- a/pr_agent/algo/ai_handler.py
+++ b/pr_agent/algo/ai_handler.py
@@ -23,39 +23,43 @@ class AiHandler:
         Initializes the OpenAI API key and other settings from a configuration file.
         Raises a ValueError if the OpenAI key is missing.
         """
-        try:
+        self.azure = False
+
+        if get_settings().get("OPENAI.KEY", None):
             openai.api_key = get_settings().openai.key
             litellm.openai_key = get_settings().openai.key
-            if get_settings().get("litellm.use_client"):
-                litellm_token = get_settings().get("litellm.LITELLM_TOKEN")
-                assert litellm_token, "LITELLM_TOKEN is required"
-                os.environ["LITELLM_TOKEN"] = litellm_token
-                litellm.use_client = True
-            self.azure = False
-            if get_settings().get("OPENAI.ORG", None):
-                litellm.organization = get_settings().openai.org
-            if get_settings().get("OPENAI.API_TYPE", None):
-                if get_settings().openai.api_type == "azure":
-                    self.azure = True
-                    litellm.azure_key = get_settings().openai.key
-            if get_settings().get("OPENAI.API_VERSION", None):
-                litellm.api_version = get_settings().openai.api_version
-            if get_settings().get("OPENAI.API_BASE", None):
-                litellm.api_base = get_settings().openai.api_base
-            if get_settings().get("ANTHROPIC.KEY", None):
-                litellm.anthropic_key = get_settings().anthropic.key
-            if get_settings().get("COHERE.KEY", None):
-                litellm.cohere_key = get_settings().cohere.key
-            if get_settings().get("REPLICATE.KEY", None):
-                litellm.replicate_key = get_settings().replicate.key
-            if get_settings().get("REPLICATE.KEY", None):
-                litellm.replicate_key = get_settings().replicate.key
-            if get_settings().get("HUGGINGFACE.KEY", None):
-                litellm.huggingface_key = get_settings().huggingface.key
-                if get_settings().get("HUGGINGFACE.API_BASE", None):
-                    litellm.api_base = get_settings().huggingface.api_base
-        except AttributeError as e:
-            raise ValueError("OpenAI key is required") from e
+        if get_settings().get("litellm.use_client"):
+            litellm_token = get_settings().get("litellm.LITELLM_TOKEN")
+            assert litellm_token, "LITELLM_TOKEN is required"
+            os.environ["LITELLM_TOKEN"] = litellm_token
+            litellm.use_client = True
+        if get_settings().get("OPENAI.ORG", None):
+            litellm.organization = get_settings().openai.org
+        if get_settings().get("OPENAI.API_TYPE", None):
+            if get_settings().openai.api_type == "azure":
+                self.azure = True
+                litellm.azure_key = get_settings().openai.key
+        if get_settings().get("OPENAI.API_VERSION", None):
+            litellm.api_version = get_settings().openai.api_version
+        if get_settings().get("OPENAI.API_BASE", None):
+            litellm.api_base = get_settings().openai.api_base
+        if get_settings().get("ANTHROPIC.KEY", None):
+            litellm.anthropic_key = get_settings().anthropic.key
+        if get_settings().get("COHERE.KEY", None):
+            litellm.cohere_key = get_settings().cohere.key
+        if get_settings().get("REPLICATE.KEY", None):
+            litellm.replicate_key = get_settings().replicate.key
+        if get_settings().get("REPLICATE.KEY", None):
+            litellm.replicate_key = get_settings().replicate.key
+        if get_settings().get("HUGGINGFACE.KEY", None):
+            litellm.huggingface_key = get_settings().huggingface.key
+            if get_settings().get("HUGGINGFACE.API_BASE", None):
+                litellm.api_base = get_settings().huggingface.api_base
+        if get_settings().get("VERTEXAI.VERTEX_PROJECT", None):
+            litellm.vertex_project = get_settings().vertexai.vertex_project
+            litellm.vertex_location = get_settings().get(
+                "VERTEXAI.VERTEX_LOCATION", None
+            )
 
     @property
     def deployment_id(self):
diff --git a/pr_agent/settings/.secrets_template.toml b/pr_agent/settings/.secrets_template.toml
index b6b11cd4..ba51382c 100644
--- a/pr_agent/settings/.secrets_template.toml
+++ b/pr_agent/settings/.secrets_template.toml
@@ -36,6 +36,10 @@ api_base = "" # the base url for your huggingface inference endpoint
 [ollama]
 api_base = "" # the base url for your local Llama 2, Code Llama, and other models inference endpoint. Acquire through https://ollama.ai/
 
+[vertexai]
+vertex_project = "" # the google cloud platform project name for your vertexai deployment
+vertex_location = "" # the google cloud platform location for your vertexai deployment
+
 [github]
 # ---- Set the following only for deployment type == "user"
 user_token = ""  # A GitHub personal access token with 'repo' scope.
diff --git a/requirements.txt b/requirements.txt
index 8589b30b..eae08f4c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -13,7 +13,7 @@ atlassian-python-api==3.39.0
 GitPython==3.1.32
 PyYAML==6.0
 starlette-context==0.3.6
-litellm~=0.1.574
+litellm==0.12.5
 boto3==1.28.25
 google-cloud-storage==2.10.0
 ujson==5.8.0
@@ -22,3 +22,4 @@ msrest==0.7.1
 pinecone-client
 pinecone-datasets @ git+https://github.com/mrT23/pinecone-datasets.git@main
 loguru==0.7.2
+google-cloud-aiplatform==1.35.0