Files
crewAI/lib/crewai-tools
iris-clawd 3be2fb65dc perf: lazy-load MCP SDK and event types to reduce cold start by ~29% (#5584)
* perf: defer MCP SDK import by fixing import path in agent/core.py

- Change 'from crewai.mcp import MCPServerConfig' to direct path
  'from crewai.mcp.config import MCPServerConfig' to avoid triggering
  mcp/__init__.py which eagerly loads the full mcp SDK (~300-400ms)
- Move MCPToolResolver import into get_mcp_tools() method body since
  it's only used at runtime, not in type annotations

Saves ~200ms on 'import crewai' cold start.

* perf: lazy-load heavy MCP imports in mcp/__init__.py

MCPClient, MCPToolResolver, BaseTransport, and TransportType now use
__getattr__ lazy loading. These pull in the full mcp SDK (~400ms) but
are only needed at runtime when agents actually connect to MCP servers.

Lightweight config and filter types remain eagerly imported.

* perf: lazy-load all event type modules in events/__init__.py

Previously only agent_events were lazy-loaded; all other event type
modules (crew, flow, knowledge, llm, guardrail, logging, mcp, memory,
reasoning, skill, task, tool_usage) were eagerly imported at package
init time. Since events/__init__.py runs whenever ANY crewai.events.*
submodule is accessed, this loaded ~12 Pydantic model modules
unnecessarily.

Now all event types use the same __getattr__ lazy-loading pattern,
with TYPE_CHECKING imports preserved for IDE/type-checker support.

Saves ~550ms on 'import crewai' cold start.

* chore: remove UNKNOWN.egg-info from version control

* fix: add MCPToolResolver to TYPE_CHECKING imports

Fixes F821 (ruff) and name-defined (mypy) from lazy-loading the
MCP import. The type annotation on _mcp_resolver needs the name
available at type-check time.

* fix: bump lxml to >=5.4.0 for GHSA-vfmq-68hx-4jfw

lxml 5.3.2 has a known vulnerability. Bump to 5.4.0+ which
includes the fix (libxml2 2.13.8). The previous <5.4.0 pin
was for etree import issues that have since been resolved.

* fix: bump exclude-newer to 2026-04-22 for lxml 6.1.0 resolution

lxml 6.1.0 (GHSA fix) was released April 17 but the exclude-newer
date was set to April 17, missing it by timestamp. Bump to April 22.

* perf: add import time benchmark script

scripts/benchmark_import_time.py measures import crewai cold start
in fresh subprocesses. Supports --runs, --json (for CI), and
--threshold (fail if median exceeds N seconds).

The companion GitHub Action workflow needs to be pushed separately
(requires workflow scope).

* new action

* Potential fix for pull request finding 'CodeQL / Workflow does not contain permissions'

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

---------

Co-authored-by: Joao Moura <joaomdmoura@gmail.com>
Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>
2026-04-22 02:17:33 -03:00
..
2025-10-20 14:10:19 -07:00

Logo of crewAI, two people rowing on a boat

CrewAI Tools

Empower your CrewAI agents with powerful, customizable tools to elevate their capabilities and tackle sophisticated, real-world tasks.

CrewAI Tools provide the essential functionality to extend your agents, helping you rapidly enhance your automations with reliable, ready-to-use tools or custom-built solutions tailored precisely to your needs.


Homepage | Documentation | Examples | Community


Available Tools

CrewAI provides an extensive collection of powerful tools ready to enhance your agents:

  • File Management: FileReadTool, FileWriteTool
  • Web Scraping: ScrapeWebsiteTool, SeleniumScrapingTool
  • Database Integrations: MySQLSearchTool
  • Vector Database Integrations: MongoDBVectorSearchTool, QdrantVectorSearchTool, WeaviateVectorSearchTool
  • API Integrations: SerperApiTool, EXASearchTool
  • AI-powered Tools: DallETool, VisionTool, StagehandTool

And many more robust tools to simplify your agent integrations.


Creating Custom Tools

CrewAI offers two straightforward approaches to creating custom tools:

Subclassing BaseTool

Define your tool by subclassing:

from crewai.tools import BaseTool

class MyCustomTool(BaseTool):
    name: str = "Tool Name"
    description: str = "Detailed description here."

    def _run(self, *args, **kwargs):
        # Your tool logic here

Using the tool Decorator

Quickly create lightweight tools using decorators:

from crewai import tool

@tool("Tool Name")
def my_custom_function(input):
    # Tool logic here
    return output

CrewAI Tools and MCP

CrewAI Tools supports the Model Context Protocol (MCP). It gives you access to thousands of tools from the hundreds of MCP servers out there built by the community.

Before you start using MCP with CrewAI tools, you need to install the mcp extra dependencies:

pip install crewai-tools[mcp]
# or
uv add crewai-tools --extra mcp

To quickly get started with MCP in CrewAI you have 2 options:

Option 1: Fully managed connection

In this scenario we use a contextmanager (with statement) to start and stop the the connection with the MCP server. This is done in the background and you only get to interact with the CrewAI tools corresponding to the MCP server's tools.

For an STDIO based MCP server:

from mcp import StdioServerParameters
from crewai_tools import MCPServerAdapter

serverparams = StdioServerParameters(
    command="uvx",
    args=["--quiet", "pubmedmcp@0.1.3"],
    env={"UV_PYTHON": "3.12", **os.environ},
)

with MCPServerAdapter(serverparams) as tools:
    # tools is now a list of CrewAI Tools matching 1:1 with the MCP server's tools
    agent = Agent(..., tools=tools)
    task = Task(...)
    crew = Crew(..., agents=[agent], tasks=[task])
    crew.kickoff(...)

For an SSE based MCP server:

serverparams = {"url": "http://localhost:8000/sse"}
with MCPServerAdapter(serverparams) as tools:
    # tools is now a list of CrewAI Tools matching 1:1 with the MCP server's tools
    agent = Agent(..., tools=tools)
    task = Task(...)
    crew = Crew(..., agents=[agent], tasks=[task])
    crew.kickoff(...)

Option 2: More control over the MCP connection

If you need more control over the MCP connection, you can instanciate the MCPServerAdapter into an mcp_server_adapter object which can be used to manage the connection with the MCP server and access the available tools.

important: in this case you need to call mcp_server_adapter.stop() to make sure the connection is correctly stopped. We recommend that you use a try ... finally block run to make sure the .stop() is called even in case of errors.

Here is the same example for an STDIO MCP Server:

from mcp import StdioServerParameters
from crewai_tools import MCPServerAdapter

serverparams = StdioServerParameters(
    command="uvx",
    args=["--quiet", "pubmedmcp@0.1.3"],
    env={"UV_PYTHON": "3.12", **os.environ},
)

try:
    mcp_server_adapter = MCPServerAdapter(serverparams)
    tools = mcp_server_adapter.tools
    # tools is now a list of CrewAI Tools matching 1:1 with the MCP server's tools
    agent = Agent(..., tools=tools)
    task = Task(...)
    crew = Crew(..., agents=[agent], tasks=[task])
    crew.kickoff(...)

# ** important ** don't forget to stop the connection
finally: 
    mcp_server_adapter.stop()

And finally the same thing but for an SSE MCP Server:

from mcp import StdioServerParameters
from crewai_tools import MCPServerAdapter

serverparams = {"url": "http://localhost:8000/sse"}

try:
    mcp_server_adapter = MCPServerAdapter(serverparams)
    tools = mcp_server_adapter.tools
    # tools is now a list of CrewAI Tools matching 1:1 with the MCP server's tools
    agent = Agent(..., tools=tools)
    task = Task(...)
    crew = Crew(..., agents=[agent], tasks=[task])
    crew.kickoff(...)

# ** important ** don't forget to stop the connection
finally: 
    mcp_server_adapter.stop()

Considerations & Limitations

Staying Safe with MCP

Always make sure that you trust the MCP Server before using it. Using an STDIO server will execute code on your machine. Using SSE is still not a silver bullet with many injection possible into your application from a malicious MCP server.

Limitations

  • At this time we only support tools from MCP Server not other type of primitives like prompts, resources...
  • We only return the first text output returned by the MCP Server tool using .content[0].text

Why Use CrewAI Tools?

  • Simplicity & Flexibility: Easy-to-use yet powerful enough for complex workflows.
  • Rapid Integration: Seamlessly incorporate external services, APIs, and databases.
  • Enterprise Ready: Built for stability, performance, and consistent results.

Contribution Guidelines

We welcome contributions from the community!

  1. Fork and clone the repository.
  2. Create a new branch (git checkout -b feature/my-feature).
  3. Commit your changes (git commit -m 'Add my feature').
  4. Push your branch (git push origin feature/my-feature).
  5. Open a pull request.

Developer Quickstart

pip install crewai[tools]

Development Setup

  • Install dependencies: uv sync
  • Run tests: uv run pytest
  • Run static type checking: uv run pyright
  • Set up pre-commit hooks: pre-commit install

Support and Community

Join our rapidly growing community and receive real-time support:

Build smarter, faster, and more powerful AI solutions—powered by CrewAI Tools.