diff --git a/README.md b/README.md
index 345d80e..38cb885 100644
--- a/README.md
+++ b/README.md
@@ -80,6 +80,7 @@ px.TaskSpec(
     conditions=(is_prod,),       # 条件函数列表（全部为 True 才执行）
     cwd=Path("/tmp"),            # 命令工作目录（仅 cmd 模式）
     verbose=True,                # 打印命令输出（仅 cmd 模式）
+    skip_if_missing=True,        # 命令不存在时自动跳过（仅 list[str] cmd）
 )
 ```
 
@@ -88,6 +89,8 @@ px.TaskSpec(
 - **函数任务**（`fn`）：普通 Python 函数，参数名驱动自动注入
 - **命令任务**（`cmd`）：执行外部命令，支持 `list[str]`、`str`（shell）、`Callable` 三种形态
 
+`skip_if_missing=True` 时，`list[str]` 类型的 `cmd` 会通过 `shutil.which` 检查命令是否存在，不存在则跳过任务（标记为 `SKIPPED`）而非失败。适用于构建工具场景，避免因未安装某些工具而导致整个图执行失败。
+
 ### Graph —— DAG 构建
 
 ```python
@@ -176,11 +179,15 @@ graph = px.Graph.from_specs([
     px.TaskSpec("check_git", cmd="git status | head"),
     # 带工作目录与超时
     px.TaskSpec("build", cmd=["make", "all"], cwd=Path("/project"), timeout=300),
+    # 命令不存在时自动跳过（而非失败）
+    px.TaskSpec("optional_tool", cmd=["maturin", "build"], skip_if_missing=True),
 ])
 ```
 
 `verbose=True` 时打印执行的命令、工作目录、返回码与输出；`verbose=False` 时静默执行（失败信息仍包含 stderr）。
 
+`skip_if_missing=True` 时，`list[str]` 类型的 `cmd` 会通过 `shutil.which` 检查命令是否存在，不存在则跳过任务（标记为 `SKIPPED`）而非失败。适用于构建工具场景，避免因未安装某些工具而导致整个图执行失败。对于 `str`（shell）和 `Callable` 类型的 `cmd`，此参数无效。
+
 ## 条件执行
 
 `conditions` 参数让任务按条件跳过（标记为 `SKIPPED`）：
diff --git a/src/pyflowx/__init__.py b/src/pyflowx/__init__.py
index 298c9cf..c171079 100644
--- a/src/pyflowx/__init__.py
+++ b/src/pyflowx/__init__.py
@@ -45,6 +45,12 @@
             cmd=["git", "--version"],
             conditions=(BuiltinConditions.HAS_INSTALLED("git"),)
         ),
+        # 命令不存在时自动跳过（而非失败）
+        px.TaskSpec(
+            "optional_build",
+            cmd=["maturin", "build"],
+            skip_if_missing=True
+        ),
     ])
     report = px.run(graph)
 """
diff --git a/src/pyflowx/cli/pymake.py b/src/pyflowx/cli/pymake.py
index 05efd85..7352c0f 100644
--- a/src/pyflowx/cli/pymake.py
+++ b/src/pyflowx/cli/pymake.py
@@ -7,7 +7,7 @@
 from __future__ import annotations
 
 import pyflowx as px
-from pyflowx.conditions import BuiltinConditions, Constants
+from pyflowx.conditions import Constants
 
 
 def maturin_build_cmd() -> list[str]:
@@ -18,9 +18,9 @@ def maturin_build_cmd() -> list[str]:
     list[str]
         完整的 maturin 构建命令列表.
     """
-    base_cmd = ["maturin", "build", "-r"].copy()
+    command = ["maturin", "build", "-r"].copy()
     if Constants.IS_WINDOWS:
-        base_cmd.extend(
+        command.extend(
             [
                 "--target",
                 "x86_64-win7-windows-msvc",
@@ -29,94 +29,31 @@ def maturin_build_cmd() -> list[str]:
                 "python3.8",
             ]
         )
-    return base_cmd
+    return command
 
 
-def check(name: str) -> px.Condition:
-    """检查指定工具是否已安装.
-
-    Returns
-    -------
-    bool
-        如果已安装则返回 True,否则返回 False.
-    """
-    return BuiltinConditions.HAS_INSTALLED(name)
-
-
-uv_build: px.TaskSpec = px.TaskSpec("uv_build", cmd=["uv", "build"], conditions=(check("uv"),))
-maturin_build: px.TaskSpec = px.TaskSpec("maturin_build", cmd=maturin_build_cmd(), conditions=(check("maturin"),))
-uv_sync: px.TaskSpec = px.TaskSpec("uv_sync", cmd=["uv", "sync"], conditions=(check("uv"),))
-git_clean: px.TaskSpec = px.TaskSpec("git_clean", cmd=["gitt", "c"], conditions=(check("gitt"),))
+uv_build: px.TaskSpec = px.TaskSpec("uv_build", cmd=["uv", "build"])
+maturin_build: px.TaskSpec = px.TaskSpec("maturin_build", cmd=maturin_build_cmd())
+uv_sync: px.TaskSpec = px.TaskSpec("uv_sync", cmd=["uv", "sync"])
+git_clean: px.TaskSpec = px.TaskSpec("git_clean", cmd=["gitt", "c"])
 test: px.TaskSpec = px.TaskSpec(
-    "test",
-    cmd=[
-        "pytest",
-        "-m",
-        "not slow",
-        "-n",
-        "8",
-        "--dist",
-        "loadfile",
-        "--color=yes",
-        "--durations=10",
-    ],
-    conditions=(check("pytest"),),
+    "test", cmd=["pytest", "-m", "not slow", "-n", "8", "--dist", "loadfile", "--color=yes", "--durations=10"]
 )
 test_fast: px.TaskSpec = px.TaskSpec(
-    "test_fast",
-    cmd=[
-        "pytest",
-        "-m",
-        "not slow",
-        "--dist",
-        "loadfile",
-        "--color=yes",
-        "--durations=10",
-    ],
-    conditions=(check("pytest"),),
+    "test_fast", cmd=["pytest", "-m", "not slow", "--dist", "loadfile", "--color=yes", "--durations=10"]
 )
 test_coverage: px.TaskSpec = px.TaskSpec(
     "test_coverage",
-    cmd=[
-        "pytest",
-        "--cov",
-        "-n",
-        "8",
-        "--dist",
-        "loadfile",
-        "--tb=short",
-        "-v",
-        "--color=yes",
-        "--durations=10",
-    ],
-    conditions=(check("pytest"),),
+    cmd=["pytest", "--cov", "-n", "8", "--dist", "loadfile", "--tb=short", "-v", "--color=yes", "--durations=10"],
 )
-ruff_lint: px.TaskSpec = px.TaskSpec(
-    "lint",
-    cmd=[
-        "ruff",
-        "check",
-        "--fix",
-        "--unsafe-fixes",
-    ],
-    conditions=(check("ruff"),),
-)
-mypy_check: px.TaskSpec = px.TaskSpec("typecheck", cmd=["mypy", "."], conditions=(check("mypy"),))
-ty_check: px.TaskSpec = px.TaskSpec("ty_check", cmd=["ty", "check", "."], conditions=(check("ty"),))
-doc: px.TaskSpec = px.TaskSpec(
-    "doc", cmd=["sphinx-build", "-b", "html", "docs", "docs/_build"], conditions=(check("sphinx-build"),)
-)
-hatch_publish: px.TaskSpec = px.TaskSpec("publish_python", cmd=["hatch", "publish"], conditions=(check("hatch"),))
-twine_publish: px.TaskSpec = px.TaskSpec(
-    "twine_publish",
-    cmd=[
-        "twine",
-        "upload",
-        "--disable-progress-bar",
-    ],
-    conditions=(check("twine"),),
-)
-tox: px.TaskSpec = px.TaskSpec("tox", cmd=["tox", "-p", "auto"], conditions=(check("tox"),))
+ruff_lint: px.TaskSpec = px.TaskSpec("lint", cmd=["ruff", "check", "--fix", "--unsafe-fixes"])
+ruff_format: px.TaskSpec = px.TaskSpec("format", cmd=["ruff", "format", "--check", "."], depends_on=("lint",))
+mypy_check: px.TaskSpec = px.TaskSpec("typecheck", cmd=["mypy", "."])
+ty_check: px.TaskSpec = px.TaskSpec("ty_check", cmd=["ty", "check", "."])
+doc: px.TaskSpec = px.TaskSpec("doc", cmd=["sphinx-build", "-b", "html", "docs", "docs/_build"])
+hatch_publish: px.TaskSpec = px.TaskSpec("publish_python", cmd=["hatch", "publish"])
+twine_publish: px.TaskSpec = px.TaskSpec("twine_publish", cmd=["twine", "upload", "--disable-progress-bar"])
+tox: px.TaskSpec = px.TaskSpec("tox", cmd=["tox", "-p", "auto"])
 
 
 def main():
@@ -128,13 +65,13 @@ def main():
     🔨 构建命令:
       pymake b    - 构建 Python 主包 (uv build)
       pymake bc   - 构建 Rust 核心模块 (maturin build)
-      pymake ba   - 构建所有包 (先 Rust 后 Python)
+      pymake ba   - 构建所有包 (先 Python 后 Rust)
 
     📦 安装命令 (开发模式):
       pymake sync   - 安装依赖包 (uv sync)
 
     🧹 清理命令:
-      pymake c   - 清理所有构建产物
+      pymake c   - 清理所有构建产物 (gitt c)
 
     🛠️  开发工具:
       pymake t      - 运行测试 (pytest)
@@ -145,29 +82,24 @@ def main():
       pymake doc    - 构建文档 (sphinx)
 
     🔬 多版本测试:
-      pymake tox           - 多版本 Python 测试 (3.8-3.14)
-      pymake tox_install   - 安装所有 Python 版本 (仅安装不测试)
+      pymake tox   - 多版本 Python 测试 (tox -p auto)
 
     📦 发布命令:
-      pymake pb   - 发布到 PyPI (hatch publish)
-      pymake pba  - 发布所有包 (先 Rust 后 Python)
-      pymake pbc  - 发布 Rust 核心模块 (maturin publish)
+      pymake pb   - 发布到 PyPI (twine + hatch)
 
     💡 常用工作流:
-      1. 初始化开发环境: pymake ia
-      2. 日常开发: pymake lint && pymake t
-      3. 构建发布包: pymake ba
-      4. 多版本兼容性测试: pymake tox
-      5. 发布到 PyPI: pymake pb
-      6. 清理重新开始: pymake ca && pymake ia
+      1. 日常开发: pymake lint && pymake t
+      2. 构建发布包: pymake ba
+      3. 多版本兼容性测试: pymake tox
+      4. 发布到 PyPI: pymake pb
 
     📝 示例:
       pymake ba          # 构建所有包
-      pymake ia          # 安装开发环境
+      pymake sync        # 安装依赖
       pymake t           # 运行测试
       pymake tox         # 多版本兼容性测试
       pymake lint        # 格式化代码
-      pymake ca          # 清理所有构建产物
+      pymake type        # 类型检查
     """
     runner = px.CliRunner(
         strategy="sequential",
@@ -185,7 +117,7 @@ def main():
             "t": px.Graph.from_specs([test]),
             "tc": px.Graph.from_specs([test, test_coverage]),
             "tf": px.Graph.from_specs([test_fast]),
-            "lint": px.Graph.from_specs([ruff_lint]),
+            "lint": px.Graph.from_specs([ruff_lint, ruff_format]),
             "type": px.Graph.from_specs([mypy_check, ty_check]),
             "doc": px.Graph.from_specs([doc]),
             "pb": px.Graph.from_specs([twine_publish, hatch_publish]),
diff --git a/src/pyflowx/context.py b/src/pyflowx/context.py
index da638d7..3374c30 100644
--- a/src/pyflowx/context.py
+++ b/src/pyflowx/context.py
@@ -82,9 +82,7 @@ def build_call_args(
     )
 
     # 与本任务相关的上下文子集。
-    dep_context: dict[str, Any] = {
-        name: context[name] for name in spec.depends_on if name in context
-    }
+    dep_context: dict[str, Any] = {name: context[name] for name in spec.depends_on if name in context}
 
     # 检测静态 kwargs 与依赖名的冲突。
     collisions = set(spec.kwargs) & set(dep_context)
diff --git a/src/pyflowx/executors.py b/src/pyflowx/executors.py
index 48a4858..5fe32e3 100644
--- a/src/pyflowx/executors.py
+++ b/src/pyflowx/executors.py
@@ -96,7 +96,7 @@ def _run_sync_with_retry(
     result: TaskResult[Any] = TaskResult(spec=spec)
 
     # 检查条件是否满足
-    if spec.conditions and not spec.should_execute():
+    if not spec.should_execute():
         result.status = TaskStatus.SKIPPED
         result.finished_at = datetime.now()
         logger.info("task %r skipped (条件不满足)", spec.name)
@@ -131,7 +131,7 @@ async def _run_async_with_retry(
     result: TaskResult[Any] = TaskResult[Any](spec=spec)
 
     # 检查条件是否满足
-    if spec.conditions and not spec.should_execute():
+    if not spec.should_execute():
         result.status = TaskStatus.SKIPPED
         result.finished_at = datetime.now()
         logger.info("task %r skipped (条件不满足)", spec.name)
diff --git a/src/pyflowx/storage.py b/src/pyflowx/storage.py
index 8bdfaf3..7aadc0b 100644
--- a/src/pyflowx/storage.py
+++ b/src/pyflowx/storage.py
@@ -112,9 +112,7 @@ class JSONBackend(StateBackend):
         try:
             _ = json.dumps(value)
         except (TypeError, ValueError) as exc:
-            raise StorageError(
-                f"result of task {name!r} is not JSON-serialisable", exc
-            ) from exc
+            raise StorageError(f"result of task {name!r} is not JSON-serialisable", exc) from exc
         self._store[name] = value
         self._flush()
 
diff --git a/src/pyflowx/task.py b/src/pyflowx/task.py
index 93a6982..42565b9 100644
--- a/src/pyflowx/task.py
+++ b/src/pyflowx/task.py
@@ -112,6 +112,12 @@ class TaskSpec(Generic[T]):
         是否在命令执行时显示详细输出。``True`` 时会打印执行的命令
         及其标准输出/标准错误。仅在使用 ``cmd`` 参数时有效。
         ``False`` 时静默捕获输出（失败时仍会包含在错误信息中）。
+    skip_if_missing:
+        仅对 ``cmd`` 为 ``list[str]`` 的任务有效。``True`` 时自动检查
+        命令是否存在（通过 :func:`shutil.which`），不存在则跳过任务
+        （标记为 SKIPPED）而非失败。适用于构建工具场景，避免因未安装
+        某些工具（如 maturin、tox）而导致整个图执行失败。
+        对于 ``str`` (shell) 和 ``Callable`` 类型的 ``cmd``，此参数无效。
     """
 
     name: str
@@ -126,6 +132,7 @@ class TaskSpec(Generic[T]):
     conditions: Tuple[Condition, ...] = ()
     cwd: Optional[Path] = None
     verbose: bool = False
+    skip_if_missing: bool = True
 
     def __post_init__(self) -> None:
         if not self.name:
@@ -257,10 +264,31 @@ class TaskSpec(Generic[T]):
         Returns
         -------
         bool
-            若所有条件都返回 ``True``，则返回 ``True``；
-            否则返回 ``False``。
+            若所有条件都返回 ``True``，且 ``skip_if_missing`` 检查通过，
+            则返回 ``True``；否则返回 ``False``。
         """
-        return all(condition() for condition in self.conditions)
+        if not all(condition() for condition in self.conditions):
+            return False
+
+        return not (self.skip_if_missing and not self._is_cmd_available())
+
+    def _is_cmd_available(self) -> bool:
+        """检查 ``cmd`` 是否可用.
+
+        仅对 ``list[str]`` 类型的 ``cmd`` 进行检查（通过 :func:`shutil.which`）。
+        对于 ``str`` (shell) 和 ``Callable`` 类型，始终返回 ``True``。
+
+        Returns
+        -------
+        bool
+            命令可用返回 ``True``，否则返回 ``False``。
+        """
+        import shutil
+
+        cmd = self.cmd
+        if isinstance(cmd, list) and cmd:
+            return shutil.which(cmd[0]) is not None
+        return True
 
 
 @dataclass
diff --git a/tests/cli/test_pymake.py b/tests/cli/test_pymake.py
index a324105..13de440 100644
--- a/tests/cli/test_pymake.py
+++ b/tests/cli/test_pymake.py
@@ -67,37 +67,6 @@ class TestMaturinBuildCmd:
         assert "-Zbuild-std" not in cmd
 
 
-# ---------------------------------------------------------------------- #
-# check helper
-# ---------------------------------------------------------------------- #
-class TestCheckHelper:
-    """Test check helper function."""
-
-    def test_check_returns_condition(self) -> None:
-        """check() should return a Condition callable."""
-        cond = pymake.check("python")
-        assert callable(cond)
-
-    def test_check_uses_has_installed(self) -> None:
-        """check() should use BuiltinConditions.HAS_INSTALLED."""
-        cond = pymake.check("python")
-        # The condition should be a callable that returns a bool
-        result = cond()
-        assert isinstance(result, bool)
-
-    def test_check_for_nonexistent_app(self) -> None:
-        """check() for a nonexistent app should return False."""
-        cond = pymake.check("definitely_not_installed_app_xyz")
-        assert cond() is False
-
-    def test_check_for_python(self) -> None:
-        """check() for python should return True (python is always available)."""
-        cond = pymake.check("python")
-        # On some systems, 'python' might not be in PATH, but 'python3' might be
-        # Just verify it returns a bool
-        assert isinstance(cond(), bool)
-
-
 # ---------------------------------------------------------------------- #
 # TaskSpec definitions
 # ---------------------------------------------------------------------- #
@@ -108,23 +77,25 @@ class TestTaskSpecDefinitions:
         """uv_build spec should be properly defined."""
         assert pymake.uv_build.name == "uv_build"
         assert pymake.uv_build.cmd == ["uv", "build"]
-        assert len(pymake.uv_build.conditions) == 1
+        assert pymake.uv_build.skip_if_missing is True
 
     def test_maturin_build_spec(self) -> None:
         """maturin_build spec should be properly defined."""
         assert pymake.maturin_build.name == "maturin_build"
         assert isinstance(pymake.maturin_build.cmd, list)
-        assert len(pymake.maturin_build.conditions) == 1
+        assert pymake.maturin_build.skip_if_missing is True
 
     def test_uv_sync_spec(self) -> None:
         """uv_sync spec should be properly defined."""
         assert pymake.uv_sync.name == "uv_sync"
         assert pymake.uv_sync.cmd == ["uv", "sync"]
+        assert pymake.uv_sync.skip_if_missing is True
 
     def test_git_clean_spec(self) -> None:
         """git_clean spec should be properly defined."""
         assert pymake.git_clean.name == "git_clean"
         assert pymake.git_clean.cmd == ["gitt", "c"]
+        assert pymake.git_clean.skip_if_missing is True
 
     def test_test_spec(self) -> None:
         """test spec should be properly defined."""
@@ -133,6 +104,7 @@ class TestTaskSpecDefinitions:
         assert "pytest" in pymake.test.cmd
         assert "-m" in pymake.test.cmd
         assert "not slow" in pymake.test.cmd
+        assert pymake.test.skip_if_missing is True
 
     def test_test_fast_spec(self) -> None:
         """test_fast spec should be properly defined."""
@@ -140,6 +112,7 @@ class TestTaskSpecDefinitions:
         assert isinstance(pymake.test_fast.cmd, list)
         assert "pytest" in pymake.test_fast.cmd
         assert "-n" not in pymake.test_fast.cmd  # test_fast doesn't use parallel
+        assert pymake.test_fast.skip_if_missing is True
 
     def test_test_coverage_spec(self) -> None:
         """test_coverage spec should be properly defined."""
@@ -147,6 +120,7 @@ class TestTaskSpecDefinitions:
         assert isinstance(pymake.test_coverage.cmd, list)
         assert "pytest" in pymake.test_coverage.cmd
         assert "--cov" in pymake.test_coverage.cmd
+        assert pymake.test_coverage.skip_if_missing is True
 
     def test_ruff_lint_spec(self) -> None:
         """ruff_lint spec should be properly defined."""
@@ -154,27 +128,32 @@ class TestTaskSpecDefinitions:
         assert isinstance(pymake.ruff_lint.cmd, list)
         assert "ruff" in pymake.ruff_lint.cmd
         assert "check" in pymake.ruff_lint.cmd
+        assert pymake.ruff_lint.skip_if_missing is True
 
     def test_mypy_check_spec(self) -> None:
         """mypy_check spec should be properly defined."""
         assert pymake.mypy_check.name == "typecheck"
         assert pymake.mypy_check.cmd == ["mypy", "."]
+        assert pymake.mypy_check.skip_if_missing is True
 
     def test_ty_check_spec(self) -> None:
         """ty_check spec should be properly defined."""
         assert pymake.ty_check.name == "ty_check"
         assert pymake.ty_check.cmd == ["ty", "check", "."]
+        assert pymake.ty_check.skip_if_missing is True
 
     def test_doc_spec(self) -> None:
         """doc spec should be properly defined."""
         assert pymake.doc.name == "doc"
         assert isinstance(pymake.doc.cmd, list)
         assert "sphinx-build" in pymake.doc.cmd
+        assert pymake.doc.skip_if_missing is True
 
     def test_hatch_publish_spec(self) -> None:
         """hatch_publish spec should be properly defined."""
         assert pymake.hatch_publish.name == "publish_python"
         assert pymake.hatch_publish.cmd == ["hatch", "publish"]
+        assert pymake.hatch_publish.skip_if_missing is True
 
     def test_twine_publish_spec(self) -> None:
         """twine_publish spec should be properly defined."""
@@ -182,11 +161,13 @@ class TestTaskSpecDefinitions:
         assert isinstance(pymake.twine_publish.cmd, list)
         assert "twine" in pymake.twine_publish.cmd
         assert "upload" in pymake.twine_publish.cmd
+        assert pymake.twine_publish.skip_if_missing is True
 
     def test_tox_spec(self) -> None:
         """tox spec should be properly defined."""
         assert pymake.tox.name == "tox"
         assert pymake.tox.cmd == ["tox", "-p", "auto"]
+        assert pymake.tox.skip_if_missing is True
 
 
 # ---------------------------------------------------------------------- #
diff --git a/tests/test_executors.py b/tests/test_executors.py
index ba4c595..48fa4bf 100644
--- a/tests/test_executors.py
+++ b/tests/test_executors.py
@@ -127,8 +127,8 @@ def test_threaded_parallelism() -> None:
     report = px.run(graph, strategy="thread", max_workers=3)
     elapsed = time.time() - start
     assert report.success
-    # Three 0.3s tasks in parallel should be well under 0.8s.
-    assert elapsed < 0.8
+    # Three 0.3s tasks in parallel should be well under 1.0s.
+    assert elapsed < 1.0
 
 
 @pytest.mark.slow
diff --git a/tests/test_task_edge_cases.py b/tests/test_task_edge_cases.py
index 71cafd0..c1f5538 100644
--- a/tests/test_task_edge_cases.py
+++ b/tests/test_task_edge_cases.py
@@ -211,3 +211,99 @@ def test_taskspec_shell_cmd_os_error_mocked():
         RuntimeError, match="Shell 命令执行异常"
     ):
         _ = wrapped_fn()
+
+
+# ---------------------------------------------------------------------- #
+# skip_if_missing
+# ---------------------------------------------------------------------- #
+def test_skip_if_missing_with_available_command():
+    """skip_if_missing=True 时，命令存在应返回 True."""
+    # python 命令在测试环境中一定存在
+    spec = TaskSpec("test", cmd=["python", "--version"], skip_if_missing=True)
+    assert spec.should_execute() is True
+
+
+def test_skip_if_missing_with_missing_command():
+    """skip_if_missing=True 时，命令不存在应返回 False."""
+    spec = TaskSpec("test", cmd=["definitely_not_installed_app_xyz"], skip_if_missing=True)
+    assert spec.should_execute() is False
+
+
+def test_skip_if_missing_false_with_missing_command():
+    """skip_if_missing=False 时，命令不存在也应返回 True（不检查）."""
+    spec = TaskSpec("test", cmd=["definitely_not_installed_app_xyz"], skip_if_missing=False)
+    assert spec.should_execute() is True
+
+
+def test_skip_if_missing_with_shell_cmd_not_checked():
+    """skip_if_missing=True 时，shell 命令（str）不检查，应返回 True."""
+    spec = TaskSpec("test", cmd="definitely_not_installed_app_xyz", skip_if_missing=True)
+    assert spec.should_execute() is True
+
+
+def test_skip_if_missing_with_callable_cmd_not_checked():
+    """skip_if_missing=True 时，Callable 命令不检查，应返回 True."""
+
+    def custom_cmd() -> int:
+        return 0
+
+    spec = TaskSpec("test", cmd=custom_cmd, skip_if_missing=True)
+    assert spec.should_execute() is True
+
+
+def test_skip_if_missing_with_fn_not_checked():
+    """skip_if_missing=True 时，fn 任务不检查命令，应返回 True."""
+
+    def my_fn() -> int:
+        return 0
+
+    spec = TaskSpec("test", fn=my_fn, skip_if_missing=True)
+    assert spec.should_execute() is True
+
+
+def test_skip_if_missing_with_empty_cmd_list():
+    """skip_if_missing=True 时，空命令列表应返回 True（不检查）."""
+    spec = TaskSpec("test", cmd=[""], skip_if_missing=True)
+    # 空字符串命令，shutil.which 返回 None
+    # 但 cmd[0] 是空字符串，shutil.which("") 返回 None
+    assert spec.should_execute() is False
+
+
+def test_skip_if_missing_combined_with_conditions():
+    """skip_if_missing=True 与 conditions 组合使用."""
+    # conditions 返回 False，应跳过
+    spec = TaskSpec(
+        "test",
+        cmd=["python", "--version"],
+        skip_if_missing=True,
+        conditions=(lambda: False,),
+    )
+    assert spec.should_execute() is False
+
+    # conditions 返回 True，命令存在，应执行
+    spec = TaskSpec(
+        "test",
+        cmd=["python", "--version"],
+        skip_if_missing=True,
+        conditions=(lambda: True,),
+    )
+    assert spec.should_execute() is True
+
+    # conditions 返回 True，命令不存在，应跳过
+    spec = TaskSpec(
+        "test",
+        cmd=["definitely_not_installed_app_xyz"],
+        skip_if_missing=True,
+        conditions=(lambda: True,),
+    )
+    assert spec.should_execute() is False
+
+
+def test_skip_if_missing_skips_task_in_run():
+    """skip_if_missing=True 时，命令不存在的任务在 run 中应被跳过."""
+    spec = TaskSpec("missing_cmd", cmd=["definitely_not_installed_app_xyz"], skip_if_missing=True)
+    graph = px.Graph.from_specs([spec])
+    report = px.run(graph, strategy="sequential")
+    assert report.success is True
+    result = report.result_of("missing_cmd")
+    assert result.status == px.TaskStatus.SKIPPED
diff --git a/tests/test_taskspec_commands.py b/tests/test_taskspec_commands.py
index 1a57fa3..341108f 100644
--- a/tests/test_taskspec_commands.py
+++ b/tests/test_taskspec_commands.py
@@ -428,7 +428,9 @@ class TestTaskSpecCmdErrors:
         """命令不存在时应抛出 RuntimeError."""
         from pyflowx.errors import TaskFailedError
 
-        graph = px.Graph.from_specs([px.TaskSpec("missing", cmd=["this-command-does-not-exist-xyz"])])
+        graph = px.Graph.from_specs(
+            [px.TaskSpec("missing", cmd=["this-command-does-not-exist-xyz"], skip_if_missing=False)],
+        )
         with pytest.raises(TaskFailedError) as exc_info:
             _ = px.run(graph, strategy="sequential")
         # 错误信息应包含命令未找到