diff --git a/tests/integration/extension/test_reflection.py b/tests/integration/extension/test_reflection.py
new file mode 100644
index 000000000..932e1bda3
--- /dev/null
+++ b/tests/integration/extension/test_reflection.py
@@ -0,0 +1,60 @@
+"""Integration tests for the reflection tool."""
+
+from unittest.mock import MagicMock
+
+import pytest
+
+from codegen.extensions.tools.reflection import perform_reflection
+from codegen.sdk.core.codebase import Codebase
+
+
+@pytest.fixture
+def mock_codebase():
+    """Create a mock codebase for testing."""
+    return MagicMock(spec=Codebase)
+
+
+def test_perform_reflection(mock_codebase):
+    """Test the reflection tool."""
+    # Test with basic inputs
+    result = perform_reflection(
+        context_summary="Testing the reflection tool",
+        findings_so_far="Found some interesting patterns",
+        current_challenges="Need to improve test coverage",
+        reflection_focus=None,
+        codebase=mock_codebase,
+    )
+
+    # Verify the result structure
+    assert result.status == "success"
+    assert "reflection" in result.content
+    assert "Testing the reflection tool" in result.content
+    assert "Found some interesting patterns" in result.content
+    assert "Need to improve test coverage" in result.content
+
+    # Test with a specific reflection focus
+    result = perform_reflection(
+        context_summary="Testing the reflection tool",
+        findings_so_far="Found some interesting patterns",
+        current_challenges="Need to improve test coverage",
+        reflection_focus="architecture",
+        codebase=mock_codebase,
+    )
+
+    # Verify the result includes the focus
+    assert result.status == "success"
+    assert "reflection" in result.content
+    assert "architecture" in result.content
+
+    # Test with minimal inputs
+    result = perform_reflection(
+        context_summary="Minimal test",
+        findings_so_far="Minimal findings",
+        codebase=mock_codebase,
+    )
+
+    # Verify the result with minimal inputs
+    assert result.status == "success"
+    assert "reflection" in result.content
+    assert "Minimal test" in result.content
+    assert "Minimal findings" in result.content
diff --git a/tests/integration/extension/test_relace_edit.py b/tests/integration/extension/test_relace_edit.py
new file mode 100644
index 000000000..8ee9b7af9
--- /dev/null
+++ b/tests/integration/extension/test_relace_edit.py
@@ -0,0 +1,150 @@
+"""Integration tests for the relace_edit tool."""
+
+import os
+import tempfile
+from pathlib import Path
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from codegen.extensions.tools.relace_edit import relace_edit
+from codegen.sdk.core.codebase import Codebase
+
+
+@pytest.fixture
+def temp_workspace():
+    """Create a temporary workspace for testing."""
+    with tempfile.TemporaryDirectory() as temp_dir:
+        # Create a simple file structure for testing
+        base_dir = Path(temp_dir)
+
+        # Create a simple Python file
+        test_file = base_dir / "test_file.py"
+        test_file.write_text("""
+def hello_world():
+    return 'Hello, World!'
+
+def goodbye_world():
+    return 'Goodbye, World!'
+""")
+
+        # Create a JavaScript file
+        js_file = base_dir / "test_file.js"
+        js_file.write_text("""
+function helloWorld() {
+    return 'Hello, World!';
+}
+
+function goodbyeWorld() {
+    return 'Goodbye, World!';
+}
+""")
+
+        # Create a codebase from the temp directory
+        codebase = Codebase.from_directory(str(base_dir))
+
+        yield codebase
+
+
+@pytest.mark.skipif(not os.getenv("RELACE_API"), reason="RELACE_API environment variable not set")
+def test_relace_edit_real_api(temp_workspace):
+    """Test relace_edit with the real API.
+
+    This test is skipped if the RELACE_API environment variable is not set.
+    """
+    # Test editing a Python file
+    edit_snippet = """
+# Keep existing imports
+
+# Modify hello_world function
+def hello_world():
+    print("Starting greeting")
+    return 'Hello, Modified World!'
+
+# Keep goodbye_world function
+"""
+
+    result = relace_edit(temp_workspace, "test_file.py", edit_snippet)
+    assert result.status == "success"
+
+    # Verify the file was modified correctly
+    from codegen.extensions.tools import view_file
+
+    file_content = view_file(temp_workspace, "test_file.py")
+    assert 'print("Starting greeting")' in file_content.content
+    assert "Hello, Modified World!" in file_content.content
+    assert "Goodbye, World!" in file_content.content  # Should be preserved
+
+
+@patch("codegen.extensions.tools.relace_edit.requests.post")
+def test_relace_edit_mock_api(mock_post, temp_workspace):
+    """Test relace_edit with a mocked API."""
+    # Mock the API response
+    mock_response = MagicMock()
+    mock_response.status_code = 200
+    mock_response.json.return_value = {
+        "status": "success",
+        "result": """
+def hello_world():
+    print("Mocked greeting")
+    return 'Hello, Mocked World!'
+
+def goodbye_world():
+    return 'Goodbye, World!'
+""",
+    }
+    mock_post.return_value = mock_response
+
+    # Test editing a Python file
+    edit_snippet = """
+# Modify hello_world function
+def hello_world():
+    print("Mocked greeting")
+    return 'Hello, Mocked World!'
+
+# Keep goodbye_world function
+"""
+
+    result = relace_edit(temp_workspace, "test_file.py", edit_snippet)
+    assert result.status == "success"
+
+    # Verify the API was called with the correct parameters
+    mock_post.assert_called_once()
+    args, kwargs = mock_post.call_args
+    assert "content" in kwargs["json"]
+    assert "edit_snippet" in kwargs["json"]
+
+    # Verify the file was modified correctly
+    from codegen.extensions.tools import view_file
+
+    file_content = view_file(temp_workspace, "test_file.py")
+    assert 'print("Mocked greeting")' in file_content.content
+    assert "Hello, Mocked World!" in file_content.content
+
+
+@patch("codegen.extensions.tools.relace_edit.requests.post")
+def test_relace_edit_api_error(mock_post, temp_workspace):
+    """Test relace_edit with API errors."""
+    # Mock an API error response
+    mock_response = MagicMock()
+    mock_response.status_code = 400
+    mock_response.json.return_value = {"status": "error", "error": "Invalid request"}
+    mock_post.return_value = mock_response
+
+    # Test with API error
+    result = relace_edit(temp_workspace, "test_file.py", "# Invalid edit")
+    assert result.status == "error"
+    assert "API error" in result.error
+
+    # Mock a network error
+    mock_post.side_effect = Exception("Network error")
+
+    # Test with network error
+    result = relace_edit(temp_workspace, "test_file.py", "# Invalid edit")
+    assert result.status == "error"
+    assert "Network error" in result.error
+
+    # Test with non-existent file
+    result = relace_edit(temp_workspace, "nonexistent_file.py", "# Edit")
+    assert result.status == "error"
+    assert "not found" in result.error
diff --git a/tests/integration/extension/test_slack.py b/tests/integration/extension/test_slack.py
new file mode 100644
index 000000000..470e4d13a
--- /dev/null
+++ b/tests/integration/extension/test_slack.py
@@ -0,0 +1,99 @@
+"""Integration tests for Slack tools."""
+
+from unittest.mock import MagicMock
+
+import pytest
+
+from codegen.extensions.tools.link_annotation import add_links_to_message
+from codegen.sdk.core.codebase import Codebase
+
+
+@pytest.fixture
+def mock_codebase():
+    """Create a mock codebase for testing."""
+    codebase = MagicMock(spec=Codebase)
+
+    # Mock the symbol lookup functionality
+    def mock_get_symbol(symbol_name):
+        if symbol_name in ["test_function", "TestClass"]:
+            mock_symbol = MagicMock()
+            mock_symbol.filepath = f"src/{symbol_name.lower()}.py"
+            return mock_symbol
+        return None
+
+    codebase.get_symbol.side_effect = mock_get_symbol
+
+    # Mock the file exists functionality
+    def mock_file_exists(filepath):
+        return filepath in ["src/file1.py", "src/file2.py", "src/test_function.py", "src/testclass.py"]
+
+    codebase.file_exists.side_effect = mock_file_exists
+
+    return codebase
+
+
+def test_add_links_to_message(mock_codebase):
+    """Test adding links to a Slack message."""
+    # Test with symbol names
+    message = "Check the `test_function` and `TestClass` implementations."
+    result = add_links_to_message(message, mock_codebase)
+
+    # Verify links were added for symbols
+    assert "`test_function`" not in result  # Should be replaced with a link
+    assert "`TestClass`" not in result  # Should be replaced with a link
+    assert "src/test_function.py" in result
+    assert "src/testclass.py" in result
+
+    # Test with file paths
+    message = "Look at `src/file1.py` and `src/file2.py`."
+    result = add_links_to_message(message, mock_codebase)
+
+    # Verify links were added for files
+    assert "`src/file1.py`" not in result  # Should be replaced with a link
+    assert "`src/file2.py`" not in result  # Should be replaced with a link
+    assert "src/file1.py" in result
+    assert "src/file2.py" in result
+
+    # Test with non-existent symbols and files
+    message = "Check `nonexistent_function` and `src/nonexistent.py`."
+    result = add_links_to_message(message, mock_codebase)
+
+    # Verify no links were added for non-existent items
+    assert "`nonexistent_function`" in result  # Should remain as is
+    assert "`src/nonexistent.py`" in result  # Should remain as is
+
+    # Test with mixed content
+    message = "Check `test_function` and regular text with `src/file1.py` and *markdown*."
+    result = add_links_to_message(message, mock_codebase)
+
+    # Verify links were added only for valid symbols and files
+    assert "`test_function`" not in result
+    assert "`src/file1.py`" not in result
+    assert "src/test_function.py" in result
+    assert "src/file1.py" in result
+    assert "*markdown*" in result  # Markdown should be preserved
+
+
+def test_send_slack_message():
+    """Test sending a message to Slack.
+
+    Note: This is a mock test since we can't actually send messages in the test environment.
+    """
+    # Create a mock say function
+    mock_say = MagicMock()
+
+    # Create a mock codebase
+    mock_codebase = MagicMock(spec=Codebase)
+
+    # Import the function directly to test
+    from codegen.extensions.langchain.tools import SlackSendMessageTool
+
+    # Create the tool
+    tool = SlackSendMessageTool(codebase=mock_codebase, say=mock_say)
+
+    # Test sending a message
+    result = tool._run("Test message")
+
+    # Verify the message was sent
+    mock_say.assert_called_once()
+    assert "✅ Message sent successfully" in result
diff --git a/tests/integration/extension/test_workspace_tools.py b/tests/integration/extension/test_workspace_tools.py
new file mode 100644
index 000000000..1aa99c06e
--- /dev/null
+++ b/tests/integration/extension/test_workspace_tools.py
@@ -0,0 +1,291 @@
+"""Integration tests for workspace tools."""
+
+import tempfile
+from pathlib import Path
+
+import pytest
+
+from codegen.extensions.tools import (
+    create_file,
+    delete_file,
+    edit_file,
+    list_directory,
+    rename_file,
+    view_file,
+)
+from codegen.extensions.tools.replacement_edit import replacement_edit
+from codegen.extensions.tools.search import search
+from codegen.sdk.core.codebase import Codebase
+
+
+@pytest.fixture
+def temp_workspace():
+    """Create a temporary workspace for testing."""
+    with tempfile.TemporaryDirectory() as temp_dir:
+        # Create a simple file structure for testing
+        base_dir = Path(temp_dir)
+
+        # Create a simple Python file
+        test_file = base_dir / "test_file.py"
+        test_file.write_text("def hello_world():\n    return 'Hello, World!'\n")
+
+        # Create a directory with files
+        test_dir = base_dir / "test_dir"
+        test_dir.mkdir()
+        (test_dir / "file1.txt").write_text("File 1 content")
+        (test_dir / "file2.txt").write_text("File 2 content")
+
+        # Create a nested directory
+        nested_dir = test_dir / "nested"
+        nested_dir.mkdir()
+        (nested_dir / "nested_file.txt").write_text("Nested file content")
+
+        # Create a codebase from the temp directory
+        codebase = Codebase.from_directory(str(base_dir))
+
+        yield codebase
+
+
+def test_view_file(temp_workspace):
+    """Test viewing a file."""
+    # Test viewing a file that exists
+    result = view_file(temp_workspace, "test_file.py")
+    assert result.status == "success"
+    assert "def hello_world()" in result.content
+
+    # Test viewing a file with line numbers
+    result = view_file(temp_workspace, "test_file.py", line_numbers=True)
+    assert result.status == "success"
+    assert "1|def hello_world()" in result.content
+
+    # Test viewing a file with line range
+    result = view_file(temp_workspace, "test_file.py", start_line=1, end_line=1)
+    assert result.status == "success"
+    assert "def hello_world()" in result.content
+    assert "return 'Hello, World!'" not in result.content
+
+    # Test viewing a file that doesn't exist
+    result = view_file(temp_workspace, "nonexistent_file.py")
+    assert result.status == "error"
+    assert "not found" in result.error
+
+
+def test_list_directory(temp_workspace):
+    """Test listing directory contents."""
+    # Test listing the root directory
+    result = list_directory(temp_workspace, "./")
+    assert result.status == "success"
+    assert "test_file.py" in result.content
+    assert "test_dir" in result.content
+
+    # Test listing a subdirectory
+    result = list_directory(temp_workspace, "test_dir")
+    assert result.status == "success"
+    assert "file1.txt" in result.content
+    assert "file2.txt" in result.content
+    assert "nested" in result.content
+
+    # Test listing with depth
+    result = list_directory(temp_workspace, "./", depth=2)
+    assert result.status == "success"
+    assert "test_file.py" in result.content
+    assert "test_dir" in result.content
+    assert "file1.txt" in result.content
+    assert "file2.txt" in result.content
+    assert "nested" in result.content
+
+    # Test listing a directory that doesn't exist
+    result = list_directory(temp_workspace, "nonexistent_dir")
+    assert result.status == "error"
+    assert "not found" in result.error
+
+
+def test_create_file(temp_workspace):
+    """Test creating a file."""
+    # Test creating a new file
+    result = create_file(temp_workspace, "new_file.py", "print('New file')")
+    assert result.status == "success"
+
+    # Verify the file was created
+    result = view_file(temp_workspace, "new_file.py")
+    assert result.status == "success"
+    assert "print('New file')" in result.content
+
+    # Test creating a file that already exists
+    result = create_file(temp_workspace, "test_file.py", "# Overwrite")
+    assert result.status == "error"
+    assert "already exists" in result.error
+
+    # Test creating a file in a directory that doesn't exist
+    result = create_file(temp_workspace, "nonexistent_dir/file.py", "# Content")
+    assert result.status == "error"
+    assert "directory does not exist" in result.error
+
+
+def test_edit_file(temp_workspace):
+    """Test editing a file."""
+    # Test editing an existing file
+    result = edit_file(temp_workspace, "test_file.py", "# Modified file\ndef hello_world():\n    return 'Modified!'")
+    assert result.status == "success"
+
+    # Verify the file was modified
+    result = view_file(temp_workspace, "test_file.py")
+    assert result.status == "success"
+    assert "# Modified file" in result.content
+    assert "return 'Modified!'" in result.content
+
+    # Test editing a file that doesn't exist
+    result = edit_file(temp_workspace, "nonexistent_file.py", "# Content")
+    assert result.status == "error"
+    assert "not found" in result.error
+
+
+def test_delete_file(temp_workspace):
+    """Test deleting a file."""
+    # Test deleting an existing file
+    result = delete_file(temp_workspace, "test_dir/file1.txt")
+    assert result.status == "success"
+
+    # Verify the file was deleted
+    result = list_directory(temp_workspace, "test_dir")
+    assert result.status == "success"
+    assert "file1.txt" not in result.content
+    assert "file2.txt" in result.content
+
+    # Test deleting a file that doesn't exist
+    result = delete_file(temp_workspace, "nonexistent_file.py")
+    assert result.status == "error"
+    assert "not found" in result.error
+
+
+def test_rename_file(temp_workspace):
+    """Test renaming a file."""
+    # Test renaming an existing file
+    result = rename_file(temp_workspace, "test_file.py", "renamed_file.py")
+    assert result.status == "success"
+
+    # Verify the file was renamed
+    result = list_directory(temp_workspace, "./")
+    assert result.status == "success"
+    assert "test_file.py" not in result.content
+    assert "renamed_file.py" in result.content
+
+    # Test renaming a file that doesn't exist
+    result = rename_file(temp_workspace, "nonexistent_file.py", "new_name.py")
+    assert result.status == "error"
+    assert "not found" in result.error
+
+    # Test renaming to a file that already exists
+    # First create a file
+    create_file(temp_workspace, "target_file.py", "# Target file")
+    result = rename_file(temp_workspace, "renamed_file.py", "target_file.py")
+    assert result.status == "error"
+    assert "already exists" in result.error
+
+
+def test_search(temp_workspace):
+    """Test searching the codebase."""
+    # Test searching for text
+    result = search(temp_workspace, "Hello, World!")
+    assert result.status == "success"
+    assert len(result.matches) > 0
+    assert "test_file.py" in result.matches[0]["filepath"]
+
+    # Test searching with regex
+    result = search(temp_workspace, "def.*world", use_regex=True)
+    assert result.status == "success"
+    assert len(result.matches) > 0
+
+    # Test searching with file extensions
+    result = search(temp_workspace, "content", file_extensions=[".txt"])
+    assert result.status == "success"
+    assert len(result.matches) > 0
+    assert all(".txt" in match["filepath"] for match in result.matches)
+
+    # Test searching with no matches
+    result = search(temp_workspace, "nonexistent_text")
+    assert result.status == "success"
+    assert len(result.matches) == 0
+
+
+def test_replacement_edit(temp_workspace):
+    """Test replacement edit."""
+    # Test replacing text in a file
+    result = replacement_edit(
+        temp_workspace,
+        filepath="test_file.py",
+        pattern="Hello, World!",
+        replacement="Goodbye, World!",
+    )
+    assert result.status == "success"
+
+    # Verify the replacement was made
+    result = view_file(temp_workspace, "test_file.py")
+    assert result.status == "success"
+    assert "Goodbye, World!" in result.content
+    assert "Hello, World!" not in result.content
+
+    # Test replacing with regex groups
+    result = replacement_edit(
+        temp_workspace,
+        filepath="test_file.py",
+        pattern=r"def (hello_world)\(\):",
+        replacement=r"def \1_function():",
+    )
+    assert result.status == "success"
+
+    # Verify the regex replacement was made
+    result = view_file(temp_workspace, "test_file.py")
+    assert result.status == "success"
+    assert "def hello_world_function():" in result.content
+
+    # Test replacing with line range
+    # First create a multi-line file
+    content = "Line 1\nLine 2\nLine 3\nLine 4\nLine 5"
+    create_file(temp_workspace, "lines.txt", content)
+
+    result = replacement_edit(
+        temp_workspace,
+        filepath="lines.txt",
+        pattern="Line",
+        replacement="Modified",
+        start=2,
+        end=4,
+    )
+    assert result.status == "success"
+
+    # Verify only lines in the range were modified
+    result = view_file(temp_workspace, "lines.txt")
+    assert result.status == "success"
+    assert "Line 1" in result.content
+    assert "Modified 2" in result.content
+    assert "Modified 3" in result.content
+    assert "Modified 4" in result.content
+    assert "Line 5" in result.content
+
+    # Test replacing with count
+    create_file(temp_workspace, "count.txt", "Replace Replace Replace Replace")
+
+    result = replacement_edit(
+        temp_workspace,
+        filepath="count.txt",
+        pattern="Replace",
+        replacement="Changed",
+        count=2,
+    )
+    assert result.status == "success"
+
+    # Verify only the specified number of replacements were made
+    result = view_file(temp_workspace, "count.txt")
+    assert result.status == "success"
+    assert "Changed Changed Replace Replace" in result.content
+
+    # Test replacing in a file that doesn't exist
+    result = replacement_edit(
+        temp_workspace,
+        filepath="nonexistent_file.py",
+        pattern="pattern",
+        replacement="replacement",
+    )
+    assert result.status == "error"
+    assert "not found" in result.error