Fix: Load .env before importing crew module in chat command

This fixes issue #3934 where 'crewai chat' fails when the crew has
module-level LLM instantiation that requires OPENAI_API_KEY.

The issue occurred because 'crewai chat' imports the crew module directly
using __import__(), and any module-level code executes immediately during
import. At this point, the .env file hadn't been loaded yet, so
OPENAI_API_KEY was not available in the environment.

Changes:
- Load .env file in load_crew_and_name() before importing the crew module
- Use os.environ.setdefault() to avoid overriding existing env vars
- Add comprehensive tests covering:
  - Loading crew with .env containing OPENAI_API_KEY
  - Environment variable precedence (existing vars not overridden)
  - Loading crew without .env file

Fixes #3934

Co-Authored-By: João <joao@crewai.com>

lib/crewai/src/crewai/cli/crew_chat.py

@@ -1,4 +1,5 @@
 import json
+import os
 from pathlib import Path
 import platform
 import re
@@ -11,7 +12,7 @@ import click
 from packaging import version
 import tomli
 
-from crewai.cli.utils import read_toml
+from crewai.cli.utils import load_env_vars, read_toml
 from crewai.cli.version import get_crewai_version
 from crewai.crew import Crew
 from crewai.llm import LLM, BaseLLM
@@ -328,6 +329,11 @@ def load_crew_and_name() -> tuple[Crew, str]:
     # Get the current working directory
     cwd = Path.cwd()
 
+    # Load environment variables from .env file before importing the crew module
+    env_vars = load_env_vars(cwd)
+    for key, value in env_vars.items():
+        os.environ.setdefault(key, value)
+
     # Path to the pyproject.toml file
     pyproject_path = cwd / "pyproject.toml"
     if not pyproject_path.exists():

lib/crewai/tests/cli/test_crew_chat_env_loading.py

@@ -0,0 +1,212 @@
+"""Tests for crew_chat.py environment variable loading."""
+
+import os
+from unittest.mock import Mock, patch
+
+import pytest
+
+from crewai.cli.crew_chat import load_crew_and_name
+
+
+@pytest.fixture
+def temp_crew_project(tmp_path):
+    """Create a temporary crew project with .env file."""
+    project_dir = tmp_path / "test_crew"
+    project_dir.mkdir()
+    
+    src_dir = project_dir / "src" / "test_crew"
+    src_dir.mkdir(parents=True)
+    
+    env_file = project_dir / ".env"
+    env_file.write_text("OPENAI_API_KEY=test-api-key-from-env\nMODEL=gpt-4\n")
+    
+    pyproject = project_dir / "pyproject.toml"
+    pyproject.write_text("""[project]
+name = "test_crew"
+version = "0.1.0"
+description = "Test crew"
+requires-python = ">=3.10"
+dependencies = ["crewai"]
+
+[tool.crewai]
+type = "crew"
+""")
+    
+    (src_dir / "__init__.py").write_text("")
+    
+    crew_py = src_dir / "crew.py"
+    crew_py.write_text("""from crewai import Agent, Crew, Process, Task, LLM
+from crewai.project import CrewBase, agent, crew, task
+
+default_llm = LLM(model="openai/gpt-4")
+
+@CrewBase
+class TestCrew:
+    '''Test crew'''
+
+    @agent
+    def researcher(self) -> Agent:
+        return Agent(
+            role="Researcher",
+            goal="Research topics",
+            backstory="You are a researcher",
+            llm=default_llm,
+        )
+
+    @task
+    def research_task(self) -> Task:
+        return Task(
+            description="Research {topic}",
+            expected_output="A report",
+            agent=self.researcher(),
+        )
+
+    @crew
+    def crew(self) -> Crew:
+        return Crew(
+            agents=[self.researcher()],
+            tasks=[self.research_task()],
+            process=Process.sequential,
+            verbose=True,
+        )
+""")
+    
+    config_dir = src_dir / "config"
+    config_dir.mkdir()
+    
+    agents_yaml = config_dir / "agents.yaml"
+    agents_yaml.write_text("""researcher:
+  role: Researcher
+  goal: Research topics
+  backstory: You are a researcher
+""")
+    
+    tasks_yaml = config_dir / "tasks.yaml"
+    tasks_yaml.write_text("""research_task:
+  description: Research {topic}
+  expected_output: A report
+  agent: researcher
+""")
+    
+    return project_dir
+
+
+def test_load_crew_with_env_file(temp_crew_project, monkeypatch):
+    """Test that load_crew_and_name loads .env before importing crew module."""
+    monkeypatch.chdir(temp_crew_project)
+    
+    monkeypatch.delenv("OPENAI_API_KEY", raising=False)
+    
+    with patch("crewai.llm.LLM") as mock_llm:
+        mock_llm.return_value = Mock()
+        
+        crew_instance, crew_name = load_crew_and_name()
+        
+        assert crew_instance is not None
+        assert crew_name == "TestCrew"
+        
+        assert os.environ.get("OPENAI_API_KEY") == "test-api-key-from-env"
+        assert os.environ.get("MODEL") == "gpt-4"
+
+
+def test_env_var_precedence(temp_crew_project, monkeypatch):
+    """Test that existing environment variables are not overridden by .env."""
+    monkeypatch.chdir(temp_crew_project)
+    
+    existing_key = "existing-api-key-from-shell"
+    monkeypatch.setenv("OPENAI_API_KEY", existing_key)
+    
+    with patch("crewai.llm.LLM") as mock_llm:
+        mock_llm.return_value = Mock()
+        
+        crew_instance, crew_name = load_crew_and_name()
+        
+        assert crew_instance is not None
+        assert crew_name == "TestCrew"
+        
+        assert os.environ.get("OPENAI_API_KEY") == existing_key
+        
+        assert os.environ.get("MODEL") == "gpt-4"
+
+
+def test_load_crew_without_env_file(tmp_path, monkeypatch):
+    """Test that load_crew_and_name works even without .env file."""
+    project_dir = tmp_path / "test_crew_no_env"
+    project_dir.mkdir()
+    
+    src_dir = project_dir / "src" / "test_crew_no_env"
+    src_dir.mkdir(parents=True)
+    
+    pyproject = project_dir / "pyproject.toml"
+    pyproject.write_text("""[project]
+name = "test_crew_no_env"
+version = "0.1.0"
+description = "Test crew without env"
+requires-python = ">=3.10"
+dependencies = ["crewai"]
+
+[tool.crewai]
+type = "crew"
+""")
+    
+    (src_dir / "__init__.py").write_text("")
+    
+    crew_py = src_dir / "crew.py"
+    crew_py.write_text("""from crewai import Agent, Crew, Process, Task
+from crewai.project import CrewBase, agent, crew, task
+
+@CrewBase
+class TestCrewNoEnv:
+    '''Test crew without env'''
+
+    @agent
+    def researcher(self) -> Agent:
+        return Agent(
+            role="Researcher",
+            goal="Research topics",
+            backstory="You are a researcher",
+        )
+
+    @task
+    def research_task(self) -> Task:
+        return Task(
+            description="Research {topic}",
+            expected_output="A report",
+            agent=self.researcher(),
+        )
+
+    @crew
+    def crew(self) -> Crew:
+        return Crew(
+            agents=[self.researcher()],
+            tasks=[self.research_task()],
+            process=Process.sequential,
+            verbose=True,
+        )
+""")
+    
+    config_dir = src_dir / "config"
+    config_dir.mkdir()
+    
+    agents_yaml = config_dir / "agents.yaml"
+    agents_yaml.write_text("""researcher:
+  role: Researcher
+  goal: Research topics
+  backstory: You are a researcher
+""")
+    
+    tasks_yaml = config_dir / "tasks.yaml"
+    tasks_yaml.write_text("""research_task:
+  description: Research {topic}
+  expected_output: A report
+  agent: researcher
+""")
+    
+    monkeypatch.chdir(project_dir)
+    
+    monkeypatch.setenv("OPENAI_API_KEY", "test-key")
+    
+    crew_instance, crew_name = load_crew_and_name()
+    
+    assert crew_instance is not None
+    assert crew_name == "TestCrewNoEnv"