> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vijil.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Google Vertex AI

> Legacy Google Vertex AI integration docs copied from the integrations-section branch.

You can evaluate the Gemini series of LLMs, [available through APIs](https://cloud.google.com/vertex-ai/generative-ai/docs/model-reference/inference) in Google Vertex AI, using Vijil Evaluate.

## Prerequisites

* You have a Google Cloud project with Vertex AI enabled.
* You have appropriate credentials (for example, Application Default Credentials) with permission to call Vertex AI generative models.
* You have access to a Vijil team and permission to manage **[Keys](https://evaluate.vijil.ai/keys)** and **[Agents](/tutorials/manage-agents/)**.

## Store Credentials

First, you need to store credentials from your Google Cloud account as API key configuration in Evaluate. To do so, follow the instructions [here](https://cloud.google.com/docs/authentication/application-default-credentials) to log into your account from a command-line environment, and get the contents of the `application_default_credentials.json` file.

```bash theme={null}
gcloud auth application-default login
vi $HOME/.config/gcloud/application_default_credentials.json
# {
#   "account": "",
#   "client_id": "XXX.apps.googleusercontent.com",
#   "client_secret": "d-FLXXX",
#   "quota_project_id": "xxx-xxx",
#   "refresh_token": "xxx-123",
#   "type": "authorized_user",
#   "universe_domain": "googleapis.com"
# }
```

Copy the fields `client_id`, `client_secret`, `quota_project_id`, and `refresh_token`. The gcloud CLI asks you to select a region when logging in, keep that handy as well.

Now log into Vijil Evaluate, and navigate to **[Keys](https://evaluate.vijil.ai/keys) > Add new key**. From the Model Hub dropdown, select *Vertex* as your chosen hub, and add the above information in the respective fields.

Give the API key configuration a name, save it, and you are ready to go!

## Register an Agent on Vijil

Once your Vertex AI credentials are stored as an API key, you can register an agent that uses this hub from the Vijil UI:

<img src="https://mintcdn.com/vijil/t1_8aRtSIj494eFA/images/legacy/gcp.webp?fit=max&auto=format&n=t1_8aRtSIj494eFA&q=85&s=9801b06ad99a96a0bf3af5597f0f2b8b" alt="Setting up a Google Cloud-based Agent in Vjil" width="920" height="885" data-path="images/legacy/gcp.webp" />

1. Press **Register [Agent](/tutorials/manage-agents/)**.
2. Enter an [Agent](/tutorials/manage-agents/) name.
3. Select **Google Cloud** as the **Hub**.
4. Enter a model name (for example `google/gemini-2.5-pro`). See the list of supported models in the Google Cloud documentation.
5. Select an existing Vertex API key you configured earlier, or create a new one.
6. Add a **System Prompt** if you want Vijil to send a default system prompt with every request to this agent.

## Enterprise

If your organization uses enterprise-only features with Vijil:

1. Add an **MCP server URL** so the agent can access MCP tools exposed by that server.
2. Add an **A2A Agent Card URL** so this agent can participate in agent-to-agent workflows defined in your enterprise.