Crash on startup: fakeredis.aioredis.FakeConnection import error

[14NGiestas]

Bug Report

colab-mcp crashes immediately on startup with:

ImportError: cannot import name 'FakeConnection' from 'fakeredis.aioredis'

or alternatively:

ModuleNotFoundError: No module named 'fakeredis.aioredis'

Root Cause

The dependency chain is:

colab-mcp → fastmcp==2.14.5 → pydocket → docket

docket/_redis.py line 257 imports:

from fakeredis.aioredis import FakeConnection, FakeServer

This import path was changed in newer versions of fakeredis:

• Older versions: module didn't exist at fakeredis.aioredis
• Middle versions: FakeConnection existed at fakeredis.aioredis
• Newer versions: renamed to FakeRedisConnection at fakeredis.aioredis

No version of fakeredis satisfies the current unpinned dependency constraint while keeping the import working.

Reproduction

uvx git+https://github.com/googlecolab/colab-mcp

Environment

• OS: Linux (NixOS, Linux Mint)
• Python: 3.13 / 3.14
• colab-mcp version: 1.0.1 (HEAD at b9ab389)

Suggested Fix

Either:

1. Pin fakeredis to the exact version range that has FakeConnection at fakeredis.aioredis
2. Update docket/pydocket to use the new FakeRedisConnection import
3. Report upstream to the docket project

This makes the MCP server completely non-functional on any Python 3.13+ environment with a fresh install.

[shinshin86]

Workaround: pinning fakeredis==2.34.1 via uvx --with

Ran into the same crash. As a temporary workaround until docket/fastmcp is updated, pinning fakeredis to 2.34.1 (the last version where FakeConnection still exists at fakeredis.aioredis) lets colab-mcp start up successfully.

Confirmed working on macOS (darwin arm64) with Python 3.13.

CLI:

uvx --python 3.13 --with "fakeredis==2.34.1" git+https://github.com/googlecolab/colab-mcp

.mcp.json (for Claude Code / other MCP clients):

  {
    "mcpServers": {
      "colab-mcp": {
        "command": "uvx",
        "args": [
          "--python", "3.13",
          "--with", "fakeredis==2.34.1",
          "git+https://github.com/googlecolab/colab-mcp"
        ],
        "timeout": 30000
      }
    }
  }

After applying this, the server reaches Starting MCP server ColabMCP with transport stdio without the ImportError.

This is only a stopgap. The proper fix is still either pinning fakeredis upstream in colab-mcp/fastmcp or updating docket to use the new FakeRedisConnection name.