Gemini, embeddings, models, endpoints and batch prediction on Google Vertex AI, through a Google Cloud project.
Google Vertex AI ships in the w6w first-party pack. It declares 14 actions, 2 health checks, and the host runs its code in a sandbox that never sees the credential.
io.w6w.google-vertex-aiCall Google’s Vertex AI from a workflow with a Google Cloud project and IAM behind it, rather than an API key. Generate Gemini responses, count tokens before sending a prompt, turn text into embeddings, and call any publisher model’s predict method such as the text-embedding family.
On the deployed side, list and read the models in a project’s Model Registry and the endpoints serving them, and send instances to a deployed endpoint for predictions. Batch prediction jobs can be created over Cloud Storage or BigQuery input, then tracked, listed and cancelled.
Vertex AI is regional: models and endpoints live in one region, and each region is its own host. A connection carries a project and a default region, any action can override either, and a full resource name copied from a list result goes to the region it names. Sign in with Google, or use a service account for server-to-server access.
Three routes to the same 14 actions. The Workflow tab is generated from Google Vertex AI's own manifest and carries its real ids, so it is copy-pasteable; the Code and CLI examples are the same call for any action on any app, so every app-specific value in them is a blank you fill in.
batch-prediction-job-cancel Ask Vertex AI to stop a running batch prediction job.
batch-prediction-job-create Start a batch prediction job over Cloud Storage or BigQuery input.
batch-prediction-job-get Get a batch prediction job's state, completion stats and output location.
generate-content Generate a Gemini response on Vertex AI from text, chat history or multimodal parts.
get-endpoint Get an endpoint, including the models deployed on it and their traffic split.
get-publisher-model Get a Model Garden publisher model's metadata (launch stage, supported actions).
predict-endpoint Send instances to a model deployed on a Vertex AI endpoint and get predictions.
predict-publisher-model Call a publisher model's `predict` method — text-embedding models, Imagen and other non-Gemini models.
A workflow step names the app and the action, and the editor fills in the
connection when you pick one. This is the Step shape from the
workflow spec, carrying Google Vertex AI's real ids.
{
"manifestVersion": "2",
"name": "google-vertex-ai-example",
"steps": [
{
"id": "batch-prediction-job-create",
"uses": {
"app": "io.w6w.google-vertex-ai",
"action": "batch-prediction-job-create",
"connection": "conn_YOUR_CONNECTION_ID"
},
"with": {
"displayName": "<displayName>",
"model": "<model>",
"instancesFormat": "<instancesFormat>"
}
}
]
}batch-prediction-job-create batch-prediction-job-get batch-prediction-job-list count-tokens embed-content +9 more actions available
Every app-specific value here is a blank you have to fill in. An
app action is reached through the connection that authenticates it, so the
address is a connection id, not the app id — and connections belong to your account,
so a public page cannot know yours. Create one for Google Vertex AI, then fill in
the three blanks: conn_YOUR_CONNECTION_ID, the action key, and the
parameters that action declares. The call itself is real — the shape is transcribed
from the studio's own snippet builder, which prints the same kind of blanks — but
nothing in it is specific to Google Vertex AI. The Workflow tab is where this app's
real ids are.
npm install @w6w/sdkyarn add @w6w/sdkpnpm add @w6w/sdkdeno add npm:@w6w/sdkimport { W6wClient, isActionRun } from "@w6w/sdk";
// Reads W6W_BASE_URL and W6W_TOKEN from the environment when omitted.
const client = new W6wClient();
const envelope = await client.run({
urn: "conn_YOUR_CONNECTION_ID",
action: "batch-prediction-job-create",
payload: {
// projectId: "<value>",
// location: "<value>",
displayName: "<value>",
model: "<value>",
instancesFormat: "<value>",
// inputUris: "<value>",
predictionsFormat: "<value>",
outputUri: "<value>",
// modelParameters: "<value>",
// labels: "<value>",
// serviceAccount: "<value>",
},
});
if (isActionRun(envelope)) console.log(envelope.value); npm install -g @w6w/cli w6w run conn_YOUR_CONNECTION_ID --action batch-prediction-job-create --payload '{"displayName":"<value>","model":"<value>","instancesFormat":"<value>","predictionsFormat":"<value>","outputUri":"<value>"}' Give an AI agent Google Vertex AI — without giving it Google Vertex AI's credentials. One MCP endpoint exposes every app, function and workflow the caller is entitled to, as tools it can discover and run. Access is granted per team while we onboard.
One tool call{
"name": "w6w_invoke",
"arguments": {
"ref": "app:io.w6w.google-vertex-ai#batch-prediction-job-create",
"input": {
"displayName": "<displayName>",
"model": "<model>",
"instancesFormat": "<instancesFormat>"
}
}
}
Every tool names its target with a single ref. The
app: form above doesn't name a connection at all — the
host resolves which of the caller's Google Vertex AI connections to sign
with, and refuses rather than guesses when the answer is ambiguous.
The token is attached host-side, at the moment of the call. It is never a tool argument, never in the model's context, and never in a transcript — so a prompt injection has nothing to exfiltrate.
Tools are derived per end user from what that person has actually connected and is entitled to — not one shared bot identity carrying the union of everyone's access.
Multi-step work runs on the workflow engine and returns a run handle the agent can poll — retries, branching and state survive the conversation that started them.
Google Vertex AI's declared health checks are on the surface too, so an agent can tell "the vendor is down" from "your credential expired" before it burns a retry on either.
The MCP surface is part of the hosted platform. Google Vertex AI itself is MIT, and the runtime that executes it is source-available (FSL).
Google Vertex AI declares its own checks, so its health is a property of the app rather than something the host guesses at.
Open incidents for the Vertex AI products this app calls, on the Google Cloud status dashboard. Unauthenticated and unsigned.