[Bug]: Docker server fails to boot after mcp 2.0.0 release — mcp_bridge uses the removed v1 low-level API

[weike-zhang]

crawl4ai version

Docker server (deploy/docker), requirements.txt as of today (mcp>=1.18.0).

Expected Behavior

The Docker server boots and exposes the API, with the MCP layer at /mcp/sse, /mcp/ws, /mcp/schema.

Current Behavior

A fresh build/install now fails to start the server. The mcp Python SDK released v2.0.0 on 2026-07-28, and deploy/docker/requirements.txt pins mcp>=1.18.0 with no upper bound, so a fresh pip install -r deploy/docker/requirements.txt resolves mcp==2.0.0. The v2 low-level API removed the Server.list_tools/call_tool/list_resources/read_resource/list_resource_templates decorator helpers that deploy/docker/mcp_bridge.py uses, so attach_mcp() crashes at import time:

AttributeError: 'Server' object has no attribute 'list_tools'

server.py calls attach_mcp(app, ...) at module level (line ~1092), so uvicorn server:app fails on boot. .github/workflows/security.yml installs the same requirements, so CI is broken too.

Steps to Reproduce

pip install "mcp==2.0.0" fastapi uvicorn httpx anyio pydantic PyJWT
python - <<'PY'
import os, sys
sys.path.insert(0, "deploy/docker")
os.environ["CRAWL4AI_API_TOKEN"] = "x"
from fastapi import FastAPI
from mcp_bridge import attach_mcp
app = FastAPI()
attach_mcp(app, base_url="http://127.0.0.1:8020")
PY

Output: AttributeError: 'Server' object has no attribute 'list_tools'.

With pip install "mcp==1.18.0" the same code works and the MCP SSE handshake completes.

Root Cause

• mcp>=1.18.0 in deploy/docker/requirements.txt has no upper bound.
• mcp v2.0.0 (https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.0.0) removed the v1 low-level Server decorator API used by mcp_bridge.py. The v2 release notes explicitly tell non-migrated projects to keep a <2 upper bound.

Suggested Fix

Add the <2 ceiling to the requirement (as the mcp SDK maintainers recommend for projects not yet migrated to v2):

- mcp>=1.18.0
+ mcp>=1.18.0,<2

A proper migration of mcp_bridge.py to the v2 low-level API can be done separately.