[BUG] gemini-embedding models do not work via Vertex API

[Gentoli]

📋 Prerequisites

• I have searched the existing issues to avoid creating a duplicate
• By submitting this issue, you agree to follow our Code of Conduct
• I am using the latest version of the software
• I have tried to clear cache/cookies or used incognito mode (if ui-related)
• I can consistently reproduce this issue

🎯 Affected Service(s)

App Service

🚦 Impact/Severity

Blocker

🐛 Bug Description

In python ADK, vertex_ai is the wrong id for provider configured via k8s. The provider id should be gemini_vertex_ai matching the ModelConfig

kagent/python/packages/kagent-adk/src/kagent/adk/models/_embedding.py

Line 89 in fad2d0c

if provider in ("vertex_ai", "gemini"):

🔄 Steps To Reproduce

1. create new ModelConfig with vertex ai embedding model
2. create agent with memory
3. ask agent to save memory

🤔 Expected Behavior

agent saves memory

📱 Actual Behavior

memory save fails silently, but log shows it has failed to call embedding

💻 Environment

• Kagent: 0.9.12
• ADK image: cr.kagent.dev/kagent-dev/kagent/app:0.9.12

🔧 CLI Bug Report

No response

🔍 Additional Context

No response

📋 Logs

2026-07-31 22:57:54,501 - kagent.adk.models._embedding - WARNING - Unknown embedding provider 'gemini_vertex_ai'; attempting OpenAI-compatible call.
2026-07-31 22:57:54,501 - kagent.adk.models._embedding - ERROR - Error generating embedding with provider=gemini_vertex_ai model=gemini-embedding-2: Missing credentials. Please pass an `api_key`, `workload_identity`, `admin_api_key`, or set the `OPENAI_API_KEY` or `OPENAI_ADMIN_KEY` environment variable.
2026-07-31 22:57:54,501 - kagent.adk._memory_service - WARNING - Failed to generate embedding for search query

📷 Screenshots

No response

🙋 Are you willing to contribute?

• I am willing to submit a PR to fix this issue