diff --git a/pyproject.toml b/pyproject.toml
index 86597be..c70af53 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -31,3 +31,6 @@ dev = [
   "pytest>=9.0.3",
   "ruff>=0.15.10",
 ]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
diff --git a/tests/test_config.py b/tests/test_config.py
new file mode 100644
index 0000000..5fee3e7
--- /dev/null
+++ b/tests/test_config.py
@@ -0,0 +1,67 @@
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "src"))
+
+from cc_slim.engine import resolve_config
+
+
+def test_resolve_config_uses_defaults(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+    monkeypatch.setenv("OPENAI_API_KEY", "env-openai-key")
+
+    config = resolve_config(tmp_path, {})
+
+    assert config.provider == "openai"
+    assert config.model == "gpt-4.1-mini"
+    assert config.api_key == "env-openai-key"
+    assert config.base_url is None
+    assert config.max_turns == 12
+
+
+def test_resolve_config_priority_cli_over_env_over_file(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+    (tmp_path / ".cc-slim.toml").write_text(
+        """
+[cc_slim]
+provider = "anthropic"
+model = "file-model"
+api_key = "file-key"
+base_url = "https://file.example"
+max_turns = 4
+""".strip(),
+        encoding="utf-8",
+    )
+    monkeypatch.setenv("CC_SLIM_PROVIDER", "openai")
+    monkeypatch.setenv("CC_SLIM_MODEL", "env-model")
+    monkeypatch.setenv("CC_SLIM_API_KEY", "env-key")
+    monkeypatch.setenv("CC_SLIM_BASE_URL", "https://env.example")
+    monkeypatch.setenv("CC_SLIM_MAX_TURNS", "9")
+
+    config = resolve_config(
+        tmp_path,
+        {
+            "provider": "anthropic",
+            "model": "cli-model",
+            "api_key": "cli-key",
+            "base_url": "https://cli.example",
+            "max_turns": 15,
+        },
+    )
+
+    assert config.provider == "anthropic"
+    assert config.model == "cli-model"
+    assert config.api_key == "cli-key"
+    assert config.base_url == "https://cli.example"
+    assert config.max_turns == 15
+
+
+def test_resolve_config_requires_api_key(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+    monkeypatch.delenv("CC_SLIM_API_KEY", raising=False)
+    monkeypatch.delenv("OPENAI_API_KEY", raising=False)
+    monkeypatch.delenv("ANTHROPIC_API_KEY", raising=False)
+
+    with pytest.raises(ValueError, match="缺少 API key"):
+        resolve_config(tmp_path, {})
diff --git a/tests/test_tools.py b/tests/test_tools.py
new file mode 100644
index 0000000..7bdbf7b
--- /dev/null
+++ b/tests/test_tools.py
@@ -0,0 +1,57 @@
+from __future__ import annotations
+
+import json
+import sys
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "src"))
+
+from cc_slim.tools import (
+    _safe_path,
+    bash_tool,
+    edit_tool,
+    glob_tool,
+    grep_tool,
+    read_tool,
+    write_tool,
+)
+
+
+def test_safe_path_allows_workspace_children(tmp_path: Path) -> None:
+    path = _safe_path(tmp_path, "a/b.txt")
+
+    assert path == (tmp_path / "a/b.txt").resolve()
+
+
+def test_safe_path_blocks_escape(tmp_path: Path) -> None:
+    with pytest.raises(ValueError, match="路径越过工作区边界"):
+        _safe_path(tmp_path, "../outside.txt")
+
+
+def test_write_edit_read_glob_grep_flow(tmp_path: Path) -> None:
+    created = write_tool(tmp_path, {"path": "hello.py", "content": "print('hello')\n"})
+    edited = edit_tool(tmp_path, {"path": "hello.py", "content": "print('world')\n"})
+    read_back = read_tool(tmp_path, {"path": "hello.py"})
+    globbed = glob_tool(tmp_path, {"pattern": "*.py"})
+    grepped = grep_tool(tmp_path, {"pattern": "world", "path": "."})
+
+    assert created == "已创建文件: hello.py"
+    assert edited == "已修改文件: hello.py"
+    assert "1: print('world')" in read_back
+    assert globbed == "hello.py"
+    assert "hello.py:1: print('world')" in grepped
+
+
+def test_bash_tool_success(tmp_path: Path) -> None:
+    result = bash_tool(tmp_path, {"command": "cmd /c exit 0"})
+    payload = json.loads(result)
+
+    assert payload["returncode"] == 0
+
+
+def test_edit_requires_existing_file(tmp_path: Path) -> None:
+    result = edit_tool(tmp_path, {"path": "missing.txt", "content": "x"})
+
+    assert result == "文件不存在: missing.txt"