@questdb/mcp-bridge

An MCP server that connects coding agents (Claude Code, Codex, Cursor, OpenCode …) to a running QuestDB Web Console. The agent gets tools to create notebook cells, run queries, and build charts. Every action executes in the browser against your already-established QuestDB session.

Setup

Add to your MCP client's config (e.g. ~/.claude/.mcp.json):

{
  "mcpServers": {
    "questdb": {
      "command": "npx",
      "args": ["-y", "@questdb/mcp-bridge"]
    }
  }
}

Label	Value	Default Value	Description
CONSOLE_ORIGIN	origin URL	http://127.0.0.1:9000	QuestDB Web Console origin. 127.0.0.1 and localhost are interchangeable.
MCP_BRIDGE_PORT	1–65535	auto-allocated	When specified, the bridge uses a fixed port. Bridge fails to start if specified port is taken.
LOG_PATH	file path	/tmp/questdb-mcp-bridge/<ISO-ts>-<pid>.log	Override the log file location.
LOG_LEVEL	ERROR / WARN / INFO / DEBUG	INFO	DEBUG adds heartbeats and full tool payloads.

Pairing

Before any notebook / chart / SQL tool works, your browser has to pair with the bridge. The agent drives the flow.

When the agent needs to pair, it calls get_pairing_credentials and shows you both:

• A one-click deep link — open it in the tab showing your Web Console.
• A WebSocket URL + token — paste into the MCP pill at the bottom of the Web Console if the deep link doesn't land in the right tab.

Either path lands you on a consent prompt. Accept it and the agent's next tool call goes through.

Each bridge run generates a fresh port and pairing token, held only in memory. On restart the old credentials stop working — the agent will surface new ones the next time it needs to pair.

Logs

The bridge writes to stderr and to a log file. Tail the newest:

tail -F "$(ls -t /tmp/questdb-mcp-bridge/*.log | head -1)"

At default INFO:

2026-05-15T12:29:27.142Z [INFO] tool_call: run_query
2026-05-15T12:29:27.318Z [INFO] tool_result: run_query ok
2026-05-15T12:29:28.011Z [ERROR] tool_result: update_cell internal_error timeout after 15000ms

At DEBUG (full payloads as continuation lines):

2026-05-15T12:29:27.142Z [INFO] tool_call: run_query
2026-05-15T12:29:27.142Z [DEBUG]   args: {"query":"SELECT count() FROM trades"}
2026-05-15T12:29:27.318Z [INFO] tool_result: run_query ok
2026-05-15T12:29:27.318Z [DEBUG]   content: [{"type":"text","text":"..."}]

License

Apache-2.0.