hermes-agent/website/docs/guides/google-vertex.md
ethernet d84e11af4d
rip out brew + pip/PyPI wheel support (#68217)
Removes Homebrew and PyPI wheel/sdist as Hermes distribution paths while
preserving the supported source, Docker, and Nix workflows.

Changes:
- Removes the Homebrew formula, PyPI publish workflow, sdist manifest
  (MANIFEST.in), and wheel/sdist release-attachment logic from scripts/release.py.
- Keeps setuptools metadata and entry points required by editable installs
  and Docker/Nix builds, but adds a setup.py guard that rejects wheel/sdist
  builds outside a sealed Nix derivation (HERMES_NIX_BUILD=1).
- Removes pip/Homebrew install detection, PyPI update checks, the pip
  self-update path, the deprecation-banner state, the postinstall subcommand,
  wheel data-directory fallbacks in agent/i18n.py and hermes_constants.py,
  and the ACP Registry manifest/version-lockstep release logic.
- Adds /nix/store/ path detection so `nix run` / `nix profile install`
  installs (which don't set HERMES_MANAGED) are correctly identified as
  "nix" rather than falling through to "git"/"unknown".
- Retired install-method values ("pip", "homebrew") in existing
  .install_method stamps (both code-scoped and home-scoped) are ignored by
  the allowlist reader and fall through to "unknown" instead of resurrecting
  a retired enum value.
- Updates Nix packaging to ship bare runtime data (locales, optional-mcps)
  through store symlinks and wrapper env vars instead of wheel data-files.
- Removes the ACP Registry manifest/icon and their version-lockstep tests.
- Deletes or rewrites packaging, pip-update, Homebrew, and ACP Registry
  tests; adds parametrized coverage for the packaging build guard covering
  BOTH sdist and wheel paths (the guards live in separate cmdclass entries
  — a passing sdist test proves nothing about the wheel path).
- Updates installation/platform documentation and related user-facing copy.
- Adjusts the supply-chain scan so deleted install-hook files do not trigger
  a finding, while additions or modifications still require the existing
  ci-reviewed label gate.

Supported installation paths (unchanged):
- git installer (install.sh)
- Docker
- Nix/NixOS
- editable development installs (uv sync, uv pip install -e ., pip install -e .)
2026-07-22 16:51:01 -04:00

6.5 KiB

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15 Google Vertex AI Use Hermes Agent with Gemini on Google Cloud Vertex AI — OAuth2 service account or ADC, GCP billing and quotas, no static API key

Google Vertex AI

Hermes Agent supports Gemini models on Google Cloud Vertex AI through Vertex's OpenAI-compatible endpoint. Unlike the Google AI Studio provider (which uses a static API key against generativelanguage.googleapis.com), Vertex gives you enterprise-grade rate limits and GCP billing/credits, and is the right choice when you want Gemini usage to draw on your Google Cloud account rather than an AI Studio key.

:::info Vertex authenticates with OAuth2, not an API key Vertex has no static API key for the standard endpoint. Every request needs a short-lived OAuth2 access token (≈1 hour TTL) minted from either a service-account JSON or Application Default Credentials (ADC). Hermes mints and auto-refreshes these tokens for you — you never paste a token by hand. This is why pasting a temporary token into a custom provider's api_key field does not work: it expires mid-session. :::

Prerequisites

  • A Google Cloud project with the Vertex AI API enabled and billing active.
  • Credentials, one of:
    • a service-account JSON key file with the roles/aiplatform.user role, or
    • Application Default Credentials via gcloud auth application-default login (or the metadata server when running on a GCP VM).
  • google-auth — installed automatically the first time you select Vertex (lazy install). Run hermes setup to repair a managed install if that fails.

Quick Start

# Option A — service account JSON (recommended for servers / gateways)
echo "VERTEX_CREDENTIALS_PATH=/path/to/service-account.json" >> ~/.hermes/.env

# Option B — Application Default Credentials (good for local dev)
gcloud auth application-default login

# Select Vertex as your provider
hermes model
# → Choose "More providers..." → "Google Vertex AI"
# → Enter your GCP project ID (or leave blank to use the one in your credentials)
# → Choose a region (default: global)
# → Select a Gemini model

# Start chatting
hermes chat

Configuration

Vertex splits its settings by sensitivity:

  • The credential path is a pointer to a secret and lives in ~/.hermes/.env.
  • Project ID and region are non-secret routing settings and live in ~/.hermes/config.yaml.

~/.hermes/.env:

# One of these (checked in this order); omit both to use ADC:
VERTEX_CREDENTIALS_PATH=/path/to/service-account.json
GOOGLE_APPLICATION_CREDENTIALS=/path/to/service-account.json

~/.hermes/config.yaml:

model:
  default: google/gemini-3-flash-preview
  provider: vertex

vertex:
  project_id: my-gcp-project   # blank → use the project embedded in the credentials
  region: global               # "global" is required for the Gemini 3.x previews

:::tip Environment variables win over config.yaml VERTEX_PROJECT_ID and VERTEX_REGION override the vertex.project_id / vertex.region values in config.yaml. Use them for per-shell overrides; keep the durable settings in config.yaml. :::

How authentication works

  1. Hermes resolves credentials in this order: VERTEX_CREDENTIALS_PATHGOOGLE_APPLICATION_CREDENTIALS → ADC.
  2. It mints an OAuth2 access token (cloud-platform scope) and caches it, refreshing when the token is within 5 minutes of expiry.
  3. The token is handed to a standard OpenAI client pointed at the Vertex endpoint:
    https://aiplatform.googleapis.com/v1beta1/projects/{project}/locations/{region}/endpoints/openapi
    
    Regional locations use a {region}-aiplatform.googleapis.com host instead.
  4. If a session runs longer than the token lifetime and a request returns 401, Hermes re-mints the token and retries automatically. On a long-running gateway, if ADC's refresh token has itself expired, Hermes falls back to the service-account JSON when one is configured.

Available Models

Vertex requires the google/ vendor prefix on model IDs. The hermes model picker offers:

Model ID
Gemini 3.1 Pro Preview google/gemini-3.1-pro-preview
Gemini 3 Pro Preview google/gemini-3-pro-preview
Gemini 3 Flash Preview google/gemini-3-flash-preview
Gemini 3.1 Flash Lite Preview google/gemini-3.1-flash-lite-preview
Gemini 2.5 Pro google/gemini-2.5-pro
Gemini 2.5 Flash google/gemini-2.5-flash

:::note global region for Gemini 3.x The Gemini 3.x preview models are served through the global endpoint. Regional endpoints (us-central1, etc.) may 404 them. Leave region: global unless you have a specific reason to pin a region. :::

Switching Models Mid-Session

/model google/gemini-3-pro-preview
/model google/gemini-3-flash-preview

/model switches among already-configured providers and models; it does not collect new credentials. Configure Vertex with hermes model first.

Reasoning / Thinking

Vertex exposes Gemini's thinking budget through the OpenAI-compatible surface. Hermes maps its reasoning-effort setting onto extra_body.google.thinking_config automatically, so reasoning_effort works the same way it does on other Gemini surfaces.

Diagnostics

hermes doctor

The doctor reports whether Vertex credentials can be resolved (service-account path or ADC) and whether the provider is configured.

Troubleshooting

"Vertex AI credentials could not be resolved"

Hermes found neither a service-account JSON nor working ADC. Either set VERTEX_CREDENTIALS_PATH in ~/.hermes/.env, or run gcloud auth application-default login. If your project isn't embedded in the credentials, set vertex.project_id in config.yaml.

google-auth not installed

Hermes lazy-installs it the first time you select the Vertex provider. If that fails, run hermes setup to repair the managed install.

404 on Gemini 3.x models

You are probably on a regional endpoint. Set region: global in the vertex: section of config.yaml (or unset VERTEX_REGION).

403 / permission denied

The service account (or your ADC identity) needs the roles/aiplatform.user role on the project, and the Vertex AI API must be enabled for that project.