openclaw-vertex-claude

OpenClaw plugin that adds Claude model support via Google Cloud Vertex AI.

Use Claude Sonnet, Opus, and other Anthropic models through your own GCP project — no direct Anthropic API key required.

How it works

OpenClaw's built-in google-vertex provider only supports Gemini models. This plugin bridges the gap by:

1. Registering a vertex-claude provider with api: "anthropic-messages"
2. Running a lightweight local proxy (127.0.0.1:18832) that translates Anthropic Messages API requests into Vertex AI rawPredict/streamRawPredict calls
3. Handling GCP authentication via Application Default Credentials (ADC)

OpenClaw → anthropic-messages runtime → local proxy → Vertex AI → Claude

Prerequisites

• OpenClaw >= 2026.2.2
• A GCP project with the Vertex AI API enabled
• Claude model access enabled in your GCP project (request access)
• gcloud CLI installed and authenticated

Installation

openclaw plugins install @fl-penly/vertex-claude

Setup

1. Authenticate with GCP

gcloud auth application-default login

2. Set environment variables

Add these to your shell profile (.zshrc, .bashrc, etc.):

export GOOGLE_CLOUD_PROJECT="your-gcp-project-id"
export VERTEX_LOCATION="us-east5"  # optional, defaults to us-east5

3. Restart OpenClaw gateway

openclaw gateway restart

4. Activate the plugin

openclaw models auth login --provider vertex-claude

5. Verify

openclaw models list | grep vertex-claude

You should see:

vertex-claude/claude-sonnet-4-5            text+image 195k     yes   yes   configured
vertex-claude/claude-opus-4-5              text+image 195k     yes   yes   configured
vertex-claude/claude-opus-4-6              text+image 195k     yes   yes   configured
...

Usage

Switch to a Vertex Claude model:

/model vertex-claude/claude-sonnet-4-5

Or set up aliases in openclaw.json:

{
  "agents": {
    "defaults": {
      "models": {
        "vertex-claude/claude-sonnet-4-5": { "alias": "vc-sonnet" },
        "vertex-claude/claude-opus-4-5": { "alias": "vc-opus" },
        "vertex-claude/claude-opus-4-6": { "alias": "vc-opus46" }
      }
    }
  }
}

Then switch with /model vc-sonnet.

Available models

| Model ID | Description | Reasoning | |----------|-------------|-----------| | claude-sonnet-4-5 | Claude Sonnet 4.5 | No | | claude-sonnet-4-5-thinking | Claude Sonnet 4.5 with extended thinking | Yes | | claude-opus-4-5 | Claude Opus 4.5 | No | | claude-opus-4-5-thinking | Claude Opus 4.5 with extended thinking | Yes | | claude-opus-4-6 | Claude Opus 4.6 | Yes |

Configuration

Environment variables

| Variable | Required | Default | Description | |----------|----------|---------|-------------| | GOOGLE_CLOUD_PROJECT | Yes | — | GCP project ID | | VERTEX_LOCATION | No | us-east5 | Vertex AI region | | VERTEX_CLAUDE_PORT | No | 18832 | Local proxy port |

Vertex AI regions with Claude support

Not all GCP regions support Claude models. Check the Anthropic on Vertex AI docs for the latest availability. Common regions:

• us-east5
• us-central1
• europe-west1

Troubleshooting

"GOOGLE_CLOUD_PROJECT is not set"

Export the environment variable before starting OpenClaw:

export GOOGLE_CLOUD_PROJECT="your-project-id"
openclaw gateway restart

"Failed to get GCP access token"

Re-authenticate:

gcloud auth application-default login

Proxy not starting (port conflict)

Change the proxy port:

export VERTEX_CLAUDE_PORT=18833
openclaw gateway restart

403 from Vertex AI

Ensure Claude models are enabled in your GCP project. Visit Vertex AI Model Garden and enable the models you want to use.

AI-assisted setup

Have an AI assistant set this up for you — just share the setup guide:

https://github.com/FL-Penly/vertex-claude/blob/main/SETUP.md

Paste the URL into Claude Code, OpenClaw, or any AI coding assistant. It will follow the steps automatically.

Development

git clone https://github.com/FL-Penly/vertex-claude.git
cd vertex-claude
npm install

# Link for local development
ln -s "$(pwd)" ~/.openclaw/extensions/vertex-claude

# Enable the plugin
openclaw plugins enable vertex-claude
openclaw gateway restart

License

MIT