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Google Vertex AI (Gemini Enterprise Agent Platform) – project, API and credentials

Use Gemini and partner models on Google Cloud: a project with billing, the aiplatform.googleapis.com API enabled, IAM roles, and authentication via Application Default Credentials / service account (production) or an API key (testing, or express mode with no billing).

Researched · not yet run liveLast researched 25 October 2026 · Google Cloud · provider site

Researched, not yet run live. Built from the provider’s official pages (linked below). A person hasn’t walked this flow end to end yet, so check each step against the source.
Do this with verapliJSON for agents

Who owns what

A Google account owns or joins a Google Cloud project; the project is linked to a Cloud Billing account and has the Vertex AI (Agent Platform) API enabled. Quotas and spend are per project; Standard PayGo tiers are set by organisation spend.

  • Google account personal owned by youExpress mode needs a @gmail.com account; Workspace users take the standard billing path.
  • Google Cloud project project · under Google accountExpress mode creates the organisation, project and billing setup for you.
  • Cloud Billing account billingoptional · under Google Cloud projectRequired outside the express-mode free tier.
  • Service account otheroptional · under Google Cloud projectTypical production identity, granted roles/aiplatform.user and used via ADC [to verify service-account setup page].

Google now documents Vertex AI as "Gemini Enterprise Agent Platform"; the API is still aiplatform.googleapis.com.

Have ready

  • A Google Cloud project you can administer: Related registry entry google/cloud-project-run covers creating a project (Cloud Run parts not needed).
  • A Cloud Billing account linked to the project (unless using express mode free tier): Related id google/cloud-billing [to verify entry exists].
  • Credit card or other payment method for Cloud Billing · The Google Cloud Free Trial and paid billing both need a payment method; some countries also need bank account verification. [6]Needed for: Link a billing account

Steps

Steps marked “human step” are ones only you can do: verapli never signs in, submits, pays or accepts terms for you.

  1. Choose standard setup or express mode

    Express mode (@gmail.com only) gives an API key with no billing and a 90-day free tier for new users, with low rate limits. Standard setup (project + billing) is needed for production, ADC and higher quotas.

    • Guided by hand

  2. Sign up for express mode (optional)optional

    You sign in with a @gmail.com account and accept the terms; an API key is created automatically and is shown on the API Keys page. Upgrade later with "Activate now".

    • Guided by hand
    • Human step: You accept the terms
    • After: Choose standard setup or express mode

    verapli captures GOOGLE_API_KEY here by plain code: encrypted in your browser, never shown to AI.

  3. Create or select a Google Cloud project

    Pick a project in the console project selector or create one (needs the Project Creator role).

    • Guided by hand
    • Human step: You accept the terms
    • After: Choose standard setup or express mode

    Where: https://console.cloud.google.com/projectselector2/home/dashboard

  4. Enable the Vertex AI (Agent Platform) API

    Enable aiplatform.googleapis.com on the project (needs serviceusage.services.enable, e.g. Owner or Service Usage Admin), or run gcloud services enable aiplatform.googleapis.com.

    • verapli co-pilot
    • After: Link a billing account

    Where: https://console.cloud.google.com/apis/library/aiplatform.googleapis.com

  5. Grant IAM roles

    Give the calling user or service account roles/aiplatform.user (enough for most use); roles/aiplatform.admin for full control.

    • Guided by hand
    • After: Enable the Vertex AI (Agent Platform) API

    Where: https://console.cloud.google.com/iam-admin/iam

  6. Configure Application Default Credentials (recommended for production)

    Locally, install the gcloud CLI, run gcloud init then gcloud auth application-default login. In production, run as a service account with the role above. Set the project ID and location in your client.

    • Guided by hand
    • Human step: You sign in
    • After: Grant IAM roles

  7. Create an API key (testing)optional

    Alternatively create an API key for the project from the API Keys page, add restrictions, and keep it out of source control and client-side apps. Google recommends API keys for testing and ADC for production.

    • Guided by hand
    • After: Enable the Vertex AI (Agent Platform) API

    verapli captures GOOGLE_API_KEY here by plain code: encrypted in your browser, never shown to AI.

  8. Enable partner models in Model Garden (optional)optional

    For non-Google models (e.g. Claude), open the model card in Model Garden, click Enable and accept the model's terms yourself. Needs the Consumer Procurement Entitlement Manager role and an org policy that allows partner models.

    • Guided by hand
    • Human step: You accept the terms
    • After: Enable the Vertex AI (Agent Platform) API

Terms and gotchas

Plain-English summary, not legal advice. Each card links its source.

Can get you bannedThe rules say

Not for services aimed at under-18s

Generative AI Services may not be used in a site or app directed towards, or likely to be accessed by, individuals under 18. [7]

Can cost moneyThe rules say

No building competing or substitute models from outputs

You may not use AI/ML outputs to substitute or circumvent a Google model or to create or improve similar models (Google's fine-tuning/distillation features excepted). The Generative AI Prohibited Use Policy applies. [7]

Worth knowingThe rules say

Google does not train on your data by default

Google will not use Customer Data to train or fine-tune AI/ML models without your prior permission or instruction; generated output is your Customer Data. [7]

Can cost moneyThe rules say

Grounding with Google Search results cannot be cached

Grounded Results and Search Suggestions may not be cached, syndicated or trained on, apart from narrow evaluation and chat-history exceptions. [7]

Can cost moneyThe rules say

A leaked API key spends your quota and money

Anyone with your key can use your project's quota, causing charges and access to tuned models and files. Do not ship keys in mobile or web clients. [2]

What you end up with

Env varSecretFormatWhat it is
GOOGLE_CLOUD_PROJECTnot secretmy-project-…Google Cloud project ID used for Vertex AI calls
GOOGLE_CLOUD_LOCATIONnot secretglobalRegion or global endpoint for requests (global is recommended for Standard PayGo)
GOOGLE_API_KEYsecretAIza…API key for Gemini on Vertex AI (express mode or testing)

Pricing

  • Free tier: Express mode free tier for new users (90 days, no billing, low rate limits). Separately, the Google Cloud Free Trial gives new customers $300 Welcome credit for 90 days, with a payment method on file.
  • Costs: Pay-as-you-go per model usage (token-based for Gemini) under Standard PayGo; Priority PayGo, Flex PayGo and Provisioned Throughput also exist [to verify per-model prices].
  • Standard PayGo throughput thresholds rise with rolling 30-day organisation spend (e.g. Gemini Flash tier 1 2,000,000 TPM). 429 means temporary contention; retry with backoff and prefer the global endpoint.

Source [4]

For agents

The same entry as JSON: /api/v1/entries/google/vertex-ai · requirements /api/v1/requirements/google/vertex-ai · terms /api/v1/terms/google/vertex-ai.

Remote MCP (read-only, no auth)
claude mcp add --transport http verapli https://verapli.com/mcp

> "What do I need for Google Vertex AI (Gemini Enterprise Agent Platform) – project, API and credentials, and how long will it take?"
  → tools/call requirements { "provider_id": "google/vertex-ai" }

Sources

  1. Google Cloud – Set up a project and a development environment Select/create project (Project Creator role); confirm billing; enable aiplatform.googleapis.com (serviceusage.services.enable); roles/aiplatform.user suffices for most users; gcloud init and gcloud auth application-default login · accessed 25 October 2026 · official
  2. Google Cloud – Get an API key (Agent Platform) API key or ADC; API key for testing, ADC for production; express mode needs @gmail.com, Workspace users use the billing-account path; GOOGLE_API_KEY env var; key leaks spend your quota; avoid calling directly from mobile/web clients in production · accessed 25 October 2026 · official
  3. Google Cloud – Agent Platform in express mode overview Express mode for @gmail.com accounts, no billing for free tier, API key created automatically, 90-day free tier for new users, model list and 10 RPM caps for some models, Activate now to upgrade; product now named Gemini Enterprise Agent Platform · accessed 25 October 2026 · official
  4. Google Cloud – Standard PayGo Usage tiers by rolling 30-day spend set TPM thresholds per model family on the global endpoint; 429 means temporary contention; backoff and global endpoint recommended; Priority PayGo / Provisioned Throughput for assured capacity · accessed 25 October 2026 · official
  5. Google Cloud – Generative AI quotas and system limits Quotas per project shared across apps; tuned models share base model quota; most increases via console Submit request · accessed 25 October 2026 · official
  6. Google Cloud – Free Trial and Free Tier $300 Welcome credit for 90 days; credit card or other payment method required; no billing during trial unless you upgrade; eligibility excludes previous paying users · accessed 25 October 2026 · official
  7. Google Cloud – Service Specific Terms §18 no training on Customer Data without permission; §17 no using outputs to build competing or substitute models; §20(c) Generative AI Prohibited Use Policy; §20(d) not for services directed at under-18s; §20(h) prompt/output storage; §20(i) indemnity; §20(k) grounding with Google Search caching limits · accessed 25 October 2026 · official
  8. Google Cloud – Partner models for MaaS Partner models must be enabled from the Model Garden model card (accepting terms) and need the Consumer Procurement Entitlement Manager role; org policy must allow them · accessed 25 October 2026 · official

Provider rules change. This page is generated from verapli registry version 2026.1025.387; spotted something out of date? Tell us. Google Cloud is not affiliated with verapli.