SSL error for clickhouse db instances using http not https

[Tushar1729-k]

My config

{
  "mcpServers": {
    "mcp-clickhouse": {
      "command": "uv",
      "args": [
        "run",
        "--with",
        "mcp-clickhouse",
        "--python",
        "3.13",
        "mcp-clickhouse"
      ],
      "env": {
        "CLICKHOUSE_HOST": "localhost",
        "CLICKHOUSE_PORT": "8123",
        "CLICKHOUSE_USER": "default",
        "CLICKHOUSE_PASSWORD": "clickhouse",
        "CLICKHOUSE_SECURE": "false",
        "CLICKHOUSE_VERIFY": "false",
        "CLICKHOUSE_CONNECT_TIMEOUT": "30",
        "CLICKHOUSE_SEND_RECEIVE_TIMEOUT": "30"
      }
    }
  }
}

My error:

Error executing tool list_databases: Error HTTPSConnectionPool(host='localhost', port=8123): Max retries exceeded with url: /? (Caused by SSLError(SSLError(1, '[SSL: WRONG_VERSION_NUMBER] wrong version number (_ssl.c:1028)'))) executing HTTP request attempt 1 (https://localhost:8123/)

[Tushar1729-k]

Hi @iskakaushik can you please guide me as to what I am doing wrong?

[joe-clickhouse]

Hi @Tushar1729-k, i think this may have been fixed recently with a combination of updates in clickhouse-connect and mcp-clickhouse. The issue appears to stem from the way clickhouse-connect assigns the default interface value based on some other connection parameters. In some instances it may have been able to default to https even though we're telling mcp-clickhouse to not. Regardless, I'm going to put up a PR that should explicitly fix this from the mcp-clickhouse side.