fix: MCP tools not loading when tools is None

[thakoreh]

Description

Fixes #4568 - When I use mcps but tools is None, it will not load mcp tools

Problem

When using the mcps parameter without setting tools, the MCP tools were not being loaded because the code checked:

if mcps and self.tools is not None:
    self.tools.extend(mcps)

This means users who only want to use MCP tools (without any other tools) couldn't do so.

Solution

Initialize self.tools to an empty list when it's None and MCP/platform tools are provided:

if mcps:
    if self.tools is None:
        self.tools = []
    self.tools.extend(mcps)

Changes

• Modified lib/crewai/src/crewai/agent/core.py to initialize self.tools = [] when None and tools need to be added

Testing

Now this works:

agent = Agent(
    role='...',
    goal='...',
    backstory='...',
    mcps=[MCPServerHTTP(url='http://localhost:8022/mcp')]
)

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[greysonlalonde]

Please remove the context window management logic from this pr and install pre-commit hooks

[thakoreh]

Thanks for the feedback @greysonlalonde!

I've cleaned up this PR:

• Removed the context window management logic
• Reset the branch to only include the MCP tools fix (single commit)
• Only 1 file changed: lib/crewai/src/crewai/agent/core.py

The pre-commit hooks are already configured in the repo (.pre-commit-config.yaml). Ruff checks pass on the changed file.