Bug type

Regression (worked before, now fails)

Beta release blocker

No

Summary

After upgrading from 2026.4.9 to 2026.4.10, google-vertex requests that worked with OAuth/service-account authentication in the same environment now fail with 401 UNAUTHENTICATED / CREDENTIALS_MISSING.

Steps to reproduce

1. Configure OpenClaw to use google-vertex with OAuth/service-account authentication.
2. Verify the setup works on OpenClaw 2026.4.9 in the current environment.
3. Upgrade OpenClaw to 2026.4.10 without changing the Vertex credentials or environment.
4. Send a request through the same google-vertex setup.
5. Observe the 401 authentication failure below.
6. Downgrade back to 2026.4.9 and observe that the same setup works again.

Expected behavior

The same google-vertex OAuth/service-account setup that works on 2026.4.9 should continue to authenticate and complete requests on 2026.4.10.

Actual behavior

On 2026.4.10, google-vertex requests fail with a 401 authentication error instead of completing successfully.

OpenClaw version

2026.4.10

Operating system

Debian 12

Install method

npm global

Model

google-vertex/gemini-3.1-pro-preview, google-vertex/gemini-3-flash-preview

Provider / routing chain

openclaw -> google-vertex -> Vertex AI (aiplatform.googleapis.com)

Additional provider/model setup details

No response

Logs, screenshots, and evidence

lane task error: lane=session:agent:main:discord:channel:1426980503596175403 durationMs=67008 error="FailoverError: LLM error: {
  "error": {
    "code": 401,
    "message": "API keys are not supported by this API. Expected OAuth2 access token or other authentication credentials that assert a principal. See https://cloud.google.com/docs/authentication",
    "status": "UNAUTHENTICATED",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "CREDENTIALS_MISSING",
        "domain": "googleapis.com",
        "metadata": {
          "method": "google.cloud.aiplatform.v1.PredictionService.StreamGenerateContent",
          "service": "aiplatform.googleapis.com"
        }
      }
    ]
  }
}
"

Impact and severity

Affected users/systems/channels: Environments using google-vertex with OAuth/service-account authentication
Severity: High (blocks google-vertex requests in the tested setup)
Frequency: Reproduced in version comparison: fails on 2026.4.10, works on 2026.4.9 after downgrade
Consequence: google-vertex becomes unusable in the affected environment until downgraded

Additional information

This appears closely related to:

• [Bug]: google-vertex provider broken with ADC auth: "<authenticated>" sentinel passed as API key + [email protected] incompatible with Node 24 #48910
• google-vertex ADC auth broken: "<authenticated>" sentinel passed as literal API key → 401 #49191