ACP new_session failed: Invalid parameters - mcpServers configuration error

[weisisheng]

Environment

• OS: Ubuntu/Debian (Docker container)
• Python: 3.12
• Node.js: 20.x
• Package: duckdb-claude-slack (installed via uvx)
• uv version: 0.9.21

Problem

When running duckdb-claude-slack with a valid ANTHROPIC_API_KEY, the bot starts successfully but fails when processing any query with this error:

acp: FAILED with error: ACP new_session failed: Invalid parameters: {
  "details": {
    "details": {
      "_errors": [],
      "mcpServers": {
        "0": {
          "_errors": [],
          "args": {
            "_errors": [
              "Required"
            ]
          },
          "command": {
            "_errors": [
              "Required"
            ]
          },
          "env": {
            "_errors": [
              "Required"
            ]
          }
        },
        "_errors": []
      }
    }
  }
}

Reproduction Steps

1. Create a Dockerfile:

FROM python:3.12-slim

RUN apt-get update && apt-get install -y curl && \
    curl -fsSL https://deb.nodesource.com/setup_20.x | bash - && \
    apt-get install -y nodejs && \
    apt-get clean && rm -rf /var/lib/apt/lists/*

RUN pip install --no-cache-dir uv
RUN useradd -m -s /bin/bash bot
USER bot
WORKDIR /home/bot

RUN uvx --help && uvx duckdb-claude-slack --help || true

COPY --chown=bot:bot init.sql .

CMD ["uvx", "duckdb-claude-slack", "--init-sql", "init.sql"]

2. Create .env with valid tokens:

SLACK_BOT_TOKEN=xoxb-...
SLACK_APP_TOKEN=xapp-...
ANTHROPIC_API_KEY=sk-ant-...

3. Run with docker compose up
4. Mention the bot in Slack with any query

Expected Behavior

Bot should process the query and return results.

Actual Behavior

Bot fails with mcpServers configuration error. The ANTHROPIC_API_KEY is confirmed present in the container environment.

Notes

• The init.sql executes successfully (no database errors)
• Node.js is installed and accessible
• The error appears to be a Zod validation error for missing required MCP server configuration fields