Prerequisites

• I've searched the current open issues
• I've updated to the latest version of Toolbox

Toolbox version

toolbox version 0.26.0

Environment

• Toolbox version: latest
• OS: Google Cloud Run (Container)
• Database: AlloyDB for PostgreSQL

Client

ADK

1. Client: google-adk (Python SDK)
2. Version: 1.23.0
3. Example: If possible, please include your code of configuration:

from toolbox_core import ToolboxSyncClient

# MCP Toolbox connection
toolbox = ToolboxSyncClient("https://mcp-toolbox-xxxx-an.a.run.app")

# Load tools
tools = toolbox.load_toolset("catchtable-tools")

# Used with Google ADK Agent
search_agent = Agent(
    model="gemini-2.5-flash",
    name="search_agent",
    tools=[mcp_toolset],  # MCP Toolbox tools
    instruction=SEARCH_INSTRUCTION,
)

Client

sources:
  test:
    kind: "postgres"
    host: "${DB_HOST}"
    port: 5432
    database: "${DB_NAME}"
    user: "${DB_USER}"
    password: "${DB_PASSWORD}"

tools:
  - name: hybrid_search
    source: test
    statement: |
        SELECT * FROM test WHERE ...

Expected Behavior

Query should execute successfully every time.

Current Behavior

Intermittent error:

unable to execute query: ERROR: prepared statement "stmtcache_3d641e2d77e4d76b6364d972493728" does not exist (SQLSTATE 26000)

Steps to reproduce?

1. Deploy MCP Toolbox to Cloud Run with AlloyDB source
2. Configure tools.yaml with SQL queries
3. Execute queries - initially works
4. Wait for idle period or instance scaling
5. Execute query again - error occurs

Additional Details

No response