Connect Gemini Enterprise

Anvil supports two distinct Gemini Enterprise journeys. Pick one deliberately:

Journey	Choose it when	What Anvil generates
Custom MCP Server data store	One Gemini Enterprise app should call your public MCP endpoint directly	Console-first registration fields, OAuth setup, compatibility checks, and an experimental API reference
Agent Registry + Agent Gateway	You need governed discovery, gateway authorization, and engine-wide egress control	Tool spec, registry and gateway definitions, readiness, reconcile, bind, verification, and rollback scripts

Custom MCP is the shorter route. Agent Gateway changes the engine’s egress path, so it requires more coordinates, IAM evidence, and an explicit reroute acknowledgement. Do not select --surface both merely because both exist.

Before you begin: locate the source contract

The Gemini target attaches to an existing Anvil bundle; it does not discover or copy a Swagger file from Gemini Enterprise.

When anvil compile receives an OpenAPI or Swagger file, Anvil locks the exact entrypoint and its reachable local references under:

.anvil/sources/<snapshot-id>/source.json
.anvil/sources/<snapshot-id>/raw/<entrypoint>

The bundle’s air.yaml records that snapshotId, source format, and snapshot-relative entrypoint. These commands show and verify the locked source:

pnpm anvil source list
pnpm anvil source show <snapshot-id>
pnpm anvil source validate <snapshot-id>
pnpm anvil status <bundle>

For a gateway import, the import report also records the vendor export, selected API, locked OpenAPI/Swagger entrypoint, and receipt. See Import a gateway estate.

Approve only the operations you inspected, then generate the target before certification. Target files are part of the certified bundle hash.

Keep four identity planes separate

Most setup failures come from using one identity field for a different plane:

Plane	What it controls	Anvil inputs
Gemini Enterprise user sign-in	Who can open and use the app	Optional --wif locations/global/workforcePools/<pool>
MCP resource server	Which bearer token the public /mcp endpoint accepts	--server-auth, --idp, --tenant, --oauth-scope, --inbound-issuer, --inbound-audience
Agent Gateway	Which Google-managed agent may resolve, traverse, and invoke	--agent-identity-principal-set, --gateway-authorization-policy, plus IAM readiness evidence
Upstream API	How the Anvil runtime calls the API it wrapped	The generated deploy/credentials.required.yaml and skill/reference/setup.md

Workforce Identity Federation does not protect /mcp. Agent Gateway IAM does not replace the MCP bearer-token check. Inbound MCP OAuth does not supply the runtime’s outbound API credential.

Locations and project coordinates

--project is the 6–30 character lowercase Google Cloud project ID. --project-number is the complete provider-assigned numeric identity used in canonical resources; placeholders or truncated values such as 123 are rejected. Do not swap them.

--location names the Gemini Enterprise app and engine location. A canonical engine resource has this exact shape:

projects/<project-number>/locations/<location>/collections/<collection>/engines/<engine>

When supplied, --project-number must equal the project number in a canonical engine resource, and --location must equal its location. When Agent Gateway receives only an engine ID, --project-number is required so Anvil can construct the canonical resource. Anvil cannot prove offline that a project ID and project number refer to the same live project; verify that relationship before registration.

The generated Agent Gateway path deliberately supports this verified matrix:

Gemini app / engine	Agent Gateway	Manual Agent Registry
global	us-central1	global or us-central1
us	us-central1	global or us-central1
eu	europe-west1	global or europe-west1

Other app locations fail closed for the Agent Gateway journey. Custom MCP can record a valid Google-style location, but Anvil warns that you must verify current provider availability before registration.

Journey A: Custom MCP with OAuth

Your endpoint must be a public, credential-free HTTPS URL whose path is exactly /mcp. It uses MCP Streamable HTTP, not SSE.

This Entra example keeps the MCP API’s scope, issuer, and audience explicit:

pnpm anvil target gemini-enterprise <bundle> \
  --surface custom-mcp \
  --server-auth oauth \
  --endpoint https://mcp.example.com/mcp \
  --project acme-prod \
  --location global \
  --engine support-app \
  --idp entra \
  --tenant <entra-tenant-id> \
  --oauth-scope api://anvil-mcp/mcp.invoke \
  --inbound-issuer https://login.microsoftonline.com/<entra-tenant-id>/v2.0 \
  --inbound-audience api://anvil-mcp

Anvil also supports --idp okta and --idp other. Okta requires its domain in --tenant. other requires explicit HTTPS authorization and token URLs. Scopes must identify this MCP API; an unrelated scope such as Microsoft Graph User.Read is rejected. Register this fixed redirect URI with the OAuth client:

https://vertexaisearch.cloud.google.com/oauth-redirect

The generated resource server currently validates JWT access tokens. Anvil therefore rejects --idp google rather than pretending it can validate every Google token shape.

No-auth is possible only with an explicit acknowledgement:

pnpm anvil target gemini-enterprise <bundle> \
  --surface custom-mcp \
  --server-auth no-auth \
  --allow-unauthenticated-mcp \
  --endpoint https://mcp.example.com/mcp \
  --project acme-prod \
  --location global \
  --engine support-app

That leaves the public endpoint without a bearer-token gate; app sign-in and WIF do not change that fact.

Journey B: Agent Registry and Agent Gateway

This path additionally needs the numeric project identity, the exact Google-managed agent principal set, a regional authorization policy, and acknowledgement that binding changes all egress for the engine:

pnpm anvil target gemini-enterprise <bundle> \
  --surface agent-gateway \
  --server-auth oauth \
  --endpoint https://mcp.example.com/mcp \
  --project acme-prod \
  --project-number 123456789012 \
  --location global \
  --engine support-app \
  --gateway-location us-central1 \
  --registry-location global \
  --agent-identity-principal-set \
    principalSet://agents.global.org-987654321098.system.id.goog/attribute.container/projects/123456789012 \
  --gateway-authorization-policy \
    projects/acme-prod/locations/us-central1/authzPolicies/anvil-mcp \
  --idp entra \
  --tenant <entra-tenant-id> \
  --oauth-scope api://anvil-mcp/mcp.invoke \
  --inbound-issuer https://login.microsoftonline.com/<entra-tenant-id>/v2.0 \
  --inbound-audience api://anvil-mcp \
  --confirm-engine-egress-reroute

Anvil validates coordinate shape and cross-field agreement before writing a file. That is offline validation, not proof that a resource exists or that IAM is ready. Follow the generated target README: create its readiness record, verify each named permission and endpoint, reconcile owned registry/gateway resources, review readback, and bind the engine last. The generated rollback script restores the recorded previous engine configuration.

Certify, plan, then reconcile live evidence

After either target is generated:

pnpm anvil status <bundle>
pnpm anvil certify <bundle>
pnpm anvil selftest <bundle>
pnpm anvil conformance <bundle>
pnpm anvil simulate <bundle>
pnpm anvil publish <bundle> --env prod
pnpm anvil status <bundle>

target generates registration artifacts. certify proves the static bundle is internally coherent. The next three commands bind executable evidence to that exact bundle digest. publish then records a gated deployment plan; it makes no cloud API call. None of those commands proves a cloud service or Gemini registration is live.

Apply the generated deployment inputs through your delivery system, complete the console or guarded gateway steps, and retain provider readback separately. After a current local plan exists, anvil status reports operator-action-required; it does not claim a live or reconciled cloud state.