refactor(agent): streamline hook method calls and enhance error logging

- Introduced a helper method `_for_each_hook_safe` to reduce code duplication in hook method implementations.
- Updated error logging to include the method name for better traceability.
- Improved the `SkillsLoader` class by adding a new method `_skill_entries_from_dir` to simplify skill listing logic.
- Enhanced skill loading and filtering logic, ensuring workspace skills take precedence over built-in ones.
- Added comprehensive tests for `SkillsLoader` to validate functionality and edge cases.

nanobot/agent/hook.py

@@ -67,40 +67,27 @@ class CompositeHook(AgentHook):
     def wants_streaming(self) -> bool:
         return any(h.wants_streaming() for h in self._hooks)
 
-    async def before_iteration(self, context: AgentHookContext) -> None:
+    async def _for_each_hook_safe(self, method_name: str, *args: Any, **kwargs: Any) -> None:
         for h in self._hooks:
             try:
-                await h.before_iteration(context)
+                await getattr(h, method_name)(*args, **kwargs)
             except Exception:
-                logger.exception("AgentHook.before_iteration error in {}", type(h).__name__)
+                logger.exception("AgentHook.{} error in {}", method_name, type(h).__name__)
+
+    async def before_iteration(self, context: AgentHookContext) -> None:
+        await self._for_each_hook_safe("before_iteration", context)
 
     async def on_stream(self, context: AgentHookContext, delta: str) -> None:
-        for h in self._hooks:
+        await self._for_each_hook_safe("on_stream", context, delta)
-            try:
-                await h.on_stream(context, delta)
-            except Exception:
-                logger.exception("AgentHook.on_stream error in {}", type(h).__name__)
 
     async def on_stream_end(self, context: AgentHookContext, *, resuming: bool) -> None:
-        for h in self._hooks:
+        await self._for_each_hook_safe("on_stream_end", context, resuming=resuming)
-            try:
-                await h.on_stream_end(context, resuming=resuming)
-            except Exception:
-                logger.exception("AgentHook.on_stream_end error in {}", type(h).__name__)
 
     async def before_execute_tools(self, context: AgentHookContext) -> None:
-        for h in self._hooks:
+        await self._for_each_hook_safe("before_execute_tools", context)
-            try:
-                await h.before_execute_tools(context)
-            except Exception:
-                logger.exception("AgentHook.before_execute_tools error in {}", type(h).__name__)
 
     async def after_iteration(self, context: AgentHookContext) -> None:
-        for h in self._hooks:
+        await self._for_each_hook_safe("after_iteration", context)
-            try:
-                await h.after_iteration(context)
-            except Exception:
-                logger.exception("AgentHook.after_iteration error in {}", type(h).__name__)
 
     def finalize_content(self, context: AgentHookContext, content: str | None) -> str | None:
         for h in self._hooks:

nanobot/agent/skills.py

@@ -9,6 +9,16 @@ from pathlib import Path
 # Default builtin skills directory (relative to this file)
 BUILTIN_SKILLS_DIR = Path(__file__).parent.parent / "skills"
 
+# Opening ---, YAML body (group 1), closing --- on its own line; supports CRLF.
+_STRIP_SKILL_FRONTMATTER = re.compile(
+    r"^---\s*\r?\n(.*?)\r?\n---\s*\r?\n?",
+    re.DOTALL,
+)
+
+
+def _escape_xml(text: str) -> str:
+    return text.replace("&", "&amp;").replace("<", "&lt;").replace(">", "&gt;")
+
 
 class SkillsLoader:
     """
@@ -23,6 +33,22 @@ class SkillsLoader:
         self.workspace_skills = workspace / "skills"
         self.builtin_skills = builtin_skills_dir or BUILTIN_SKILLS_DIR
 
+    def _skill_entries_from_dir(self, base: Path, source: str, *, skip_names: set[str] | None = None) -> list[dict[str, str]]:
+        if not base.exists():
+            return []
+        entries: list[dict[str, str]] = []
+        for skill_dir in base.iterdir():
+            if not skill_dir.is_dir():
+                continue
+            skill_file = skill_dir / "SKILL.md"
+            if not skill_file.exists():
+                continue
+            name = skill_dir.name
+            if skip_names is not None and name in skip_names:
+                continue
+            entries.append({"name": name, "path": str(skill_file), "source": source})
+        return entries
+
     def list_skills(self, filter_unavailable: bool = True) -> list[dict[str, str]]:
         """
         List all available skills.
@@ -33,27 +59,15 @@ class SkillsLoader:
         Returns:
             List of skill info dicts with 'name', 'path', 'source'.
         """
-        skills = []
+        skills = self._skill_entries_from_dir(self.workspace_skills, "workspace")
-
+        workspace_names = {entry["name"] for entry in skills}
-        # Workspace skills (highest priority)
-        if self.workspace_skills.exists():
-            for skill_dir in self.workspace_skills.iterdir():
-                if skill_dir.is_dir():
-                    skill_file = skill_dir / "SKILL.md"
-                    if skill_file.exists():
-                        skills.append({"name": skill_dir.name, "path": str(skill_file), "source": "workspace"})
-
-        # Built-in skills
         if self.builtin_skills and self.builtin_skills.exists():
-            for skill_dir in self.builtin_skills.iterdir():
+            skills.extend(
-                if skill_dir.is_dir():
+                self._skill_entries_from_dir(self.builtin_skills, "builtin", skip_names=workspace_names)
-                    skill_file = skill_dir / "SKILL.md"
+            )
-                    if skill_file.exists() and not any(s["name"] == skill_dir.name for s in skills):
-                        skills.append({"name": skill_dir.name, "path": str(skill_file), "source": "builtin"})
 
-        # Filter by requirements
         if filter_unavailable:
-            return [s for s in skills if self._check_requirements(self._get_skill_meta(s["name"]))]
+            return [skill for skill in skills if self._check_requirements(self._get_skill_meta(skill["name"]))]
         return skills
 
     def load_skill(self, name: str) -> str | None:
@@ -66,17 +80,13 @@ class SkillsLoader:
         Returns:
             Skill content or None if not found.
         """
-        # Check workspace first
+        roots = [self.workspace_skills]
-        workspace_skill = self.workspace_skills / name / "SKILL.md"
-        if workspace_skill.exists():
-            return workspace_skill.read_text(encoding="utf-8")
-
-        # Check built-in
         if self.builtin_skills:
-            builtin_skill = self.builtin_skills / name / "SKILL.md"
+            roots.append(self.builtin_skills)
-            if builtin_skill.exists():
+        for root in roots:
-                return builtin_skill.read_text(encoding="utf-8")
+            path = root / name / "SKILL.md"
-
+            if path.exists():
+                return path.read_text(encoding="utf-8")
         return None
 
     def load_skills_for_context(self, skill_names: list[str]) -> str:
@@ -89,14 +99,12 @@ class SkillsLoader:
         Returns:
             Formatted skills content.
         """
-        parts = []
+        parts = [
-        for name in skill_names:
+            f"### Skill: {name}\n\n{self._strip_frontmatter(markdown)}"
-            content = self.load_skill(name)
+            for name in skill_names
-            if content:
+            if (markdown := self.load_skill(name))
-                content = self._strip_frontmatter(content)
+        ]
-                parts.append(f"### Skill: {name}\n\n{content}")
+        return "\n\n---\n\n".join(parts)
-
-        return "\n\n---\n\n".join(parts) if parts else ""
 
     def build_skills_summary(self) -> str:
         """
@@ -112,44 +120,36 @@ class SkillsLoader:
         if not all_skills:
             return ""
 
-        def escape_xml(s: str) -> str:
+        lines: list[str] = ["<skills>"]
-            return s.replace("&", "&amp;").replace("<", "&lt;").replace(">", "&gt;")
+        for entry in all_skills:
-
+            skill_name = entry["name"]
-        lines = ["<skills>"]
+            meta = self._get_skill_meta(skill_name)
-        for s in all_skills:
+            available = self._check_requirements(meta)
-            name = escape_xml(s["name"])
+            lines.extend(
-            path = s["path"]
+                [
-            desc = escape_xml(self._get_skill_description(s["name"]))
+                    f'  <skill available="{str(available).lower()}">',
-            skill_meta = self._get_skill_meta(s["name"])
+                    f"    <name>{_escape_xml(skill_name)}</name>",
-            available = self._check_requirements(skill_meta)
+                    f"    <description>{_escape_xml(self._get_skill_description(skill_name))}</description>",
-
+                    f"    <location>{entry['path']}</location>",
-            lines.append(f"  <skill available=\"{str(available).lower()}\">")
+                ]
-            lines.append(f"    <name>{name}</name>")
+            )
-            lines.append(f"    <description>{desc}</description>")
-            lines.append(f"    <location>{path}</location>")
-
-            # Show missing requirements for unavailable skills
             if not available:
-                missing = self._get_missing_requirements(skill_meta)
+                missing = self._get_missing_requirements(meta)
                 if missing:
-                    lines.append(f"    <requires>{escape_xml(missing)}</requires>")
+                    lines.append(f"    <requires>{_escape_xml(missing)}</requires>")
-
             lines.append("  </skill>")
         lines.append("</skills>")
-
         return "\n".join(lines)
 
     def _get_missing_requirements(self, skill_meta: dict) -> str:
         """Get a description of missing requirements."""
-        missing = []
         requires = skill_meta.get("requires", {})
-        for b in requires.get("bins", []):
+        required_bins = requires.get("bins", [])
-            if not shutil.which(b):
+        required_env_vars = requires.get("env", [])
-                missing.append(f"CLI: {b}")
+        return ", ".join(
-        for env in requires.get("env", []):
+            [f"CLI: {command_name}" for command_name in required_bins if not shutil.which(command_name)]
-            if not os.environ.get(env):
+            + [f"ENV: {env_name}" for env_name in required_env_vars if not os.environ.get(env_name)]
-                missing.append(f"ENV: {env}")
+        )
-        return ", ".join(missing)
 
     def _get_skill_description(self, name: str) -> str:
         """Get the description of a skill from its frontmatter."""
@@ -160,30 +160,32 @@ class SkillsLoader:
 
     def _strip_frontmatter(self, content: str) -> str:
         """Remove YAML frontmatter from markdown content."""
-        if content.startswith("---"):
+        if not content.startswith("---"):
-            match = re.match(r"^---\n.*?\n---\n", content, re.DOTALL)
+            return content
-            if match:
+        match = _STRIP_SKILL_FRONTMATTER.match(content)
-                return content[match.end():].strip()
+        if match:
+            return content[match.end():].strip()
         return content
 
     def _parse_nanobot_metadata(self, raw: str) -> dict:
         """Parse skill metadata JSON from frontmatter (supports nanobot and openclaw keys)."""
         try:
             data = json.loads(raw)
-            return data.get("nanobot", data.get("openclaw", {})) if isinstance(data, dict) else {}
         except (json.JSONDecodeError, TypeError):
             return {}
+        if not isinstance(data, dict):
+            return {}
+        payload = data.get("nanobot", data.get("openclaw", {}))
+        return payload if isinstance(payload, dict) else {}
 
     def _check_requirements(self, skill_meta: dict) -> bool:
         """Check if skill requirements are met (bins, env vars)."""
         requires = skill_meta.get("requires", {})
-        for b in requires.get("bins", []):
+        required_bins = requires.get("bins", [])
-            if not shutil.which(b):
+        required_env_vars = requires.get("env", [])
-                return False
+        return all(shutil.which(cmd) for cmd in required_bins) and all(
-        for env in requires.get("env", []):
+            os.environ.get(var) for var in required_env_vars
-            if not os.environ.get(env):
+        )
-                return False
-        return True
 
     def _get_skill_meta(self, name: str) -> dict:
         """Get nanobot metadata for a skill (cached in frontmatter)."""
@@ -192,13 +194,15 @@ class SkillsLoader:
 
     def get_always_skills(self) -> list[str]:
         """Get skills marked as always=true that meet requirements."""
-        result = []
+        return [
-        for s in self.list_skills(filter_unavailable=True):
+            entry["name"]
-            meta = self.get_skill_metadata(s["name"]) or {}
+            for entry in self.list_skills(filter_unavailable=True)
-            skill_meta = self._parse_nanobot_metadata(meta.get("metadata", ""))
+            if (meta := self.get_skill_metadata(entry["name"]) or {})
-            if skill_meta.get("always") or meta.get("always"):
+            and (
-                result.append(s["name"])
+                self._parse_nanobot_metadata(meta.get("metadata", "")).get("always")
-        return result
+                or meta.get("always")
+            )
+        ]
 
     def get_skill_metadata(self, name: str) -> dict | None:
         """
@@ -211,18 +215,15 @@ class SkillsLoader:
             Metadata dict or None.
         """
         content = self.load_skill(name)
-        if not content:
+        if not content or not content.startswith("---"):
             return None
-
+        match = _STRIP_SKILL_FRONTMATTER.match(content)
-        if content.startswith("---"):
+        if not match:
-            match = re.match(r"^---\n(.*?)\n---", content, re.DOTALL)
+            return None
-            if match:
+        metadata: dict[str, str] = {}
-                # Simple YAML parsing
+        for line in match.group(1).splitlines():
-                metadata = {}
+            if ":" not in line:
-                for line in match.group(1).split("\n"):
+                continue
-                    if ":" in line:
+            key, value = line.split(":", 1)
-                        key, value = line.split(":", 1)
+            metadata[key.strip()] = value.strip().strip('"\'')
-                        metadata[key.strip()] = value.strip().strip('"\'')
+        return metadata
-                return metadata
-
-        return None

tests/agent/test_skills_loader.py

@@ -0,0 +1,252 @@
+"""Tests for nanobot.agent.skills.SkillsLoader."""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+import pytest
+
+from nanobot.agent.skills import SkillsLoader
+
+
+def _write_skill(
+    base: Path,
+    name: str,
+    *,
+    metadata_json: dict | None = None,
+    body: str = "# Skill\n",
+) -> Path:
+    """Create ``base / name / SKILL.md`` with optional nanobot metadata JSON."""
+    skill_dir = base / name
+    skill_dir.mkdir(parents=True)
+    lines = ["---"]
+    if metadata_json is not None:
+        payload = json.dumps({"nanobot": metadata_json}, separators=(",", ":"))
+        lines.append(f'metadata: {payload}')
+    lines.extend(["---", "", body])
+    path = skill_dir / "SKILL.md"
+    path.write_text("\n".join(lines), encoding="utf-8")
+    return path
+
+
+def test_list_skills_empty_when_skills_dir_missing(tmp_path: Path) -> None:
+    workspace = tmp_path / "ws"
+    workspace.mkdir()
+    builtin = tmp_path / "builtin"
+    builtin.mkdir()
+    loader = SkillsLoader(workspace, builtin_skills_dir=builtin)
+    assert loader.list_skills(filter_unavailable=False) == []
+
+
+def test_list_skills_empty_when_skills_dir_exists_but_empty(tmp_path: Path) -> None:
+    workspace = tmp_path / "ws"
+    (workspace / "skills").mkdir(parents=True)
+    builtin = tmp_path / "builtin"
+    builtin.mkdir()
+    loader = SkillsLoader(workspace, builtin_skills_dir=builtin)
+    assert loader.list_skills(filter_unavailable=False) == []
+
+
+def test_list_skills_workspace_entry_shape_and_source(tmp_path: Path) -> None:
+    workspace = tmp_path / "ws"
+    skills_root = workspace / "skills"
+    skills_root.mkdir(parents=True)
+    skill_path = _write_skill(skills_root, "alpha", body="# Alpha")
+    builtin = tmp_path / "builtin"
+    builtin.mkdir()
+
+    loader = SkillsLoader(workspace, builtin_skills_dir=builtin)
+    entries = loader.list_skills(filter_unavailable=False)
+    assert entries == [
+        {"name": "alpha", "path": str(skill_path), "source": "workspace"},
+    ]
+
+
+def test_list_skills_skips_non_directories_and_missing_skill_md(tmp_path: Path) -> None:
+    workspace = tmp_path / "ws"
+    skills_root = workspace / "skills"
+    skills_root.mkdir(parents=True)
+    (skills_root / "not_a_dir.txt").write_text("x", encoding="utf-8")
+    (skills_root / "no_skill_md").mkdir()
+    ok_path = _write_skill(skills_root, "ok", body="# Ok")
+    builtin = tmp_path / "builtin"
+    builtin.mkdir()
+
+    loader = SkillsLoader(workspace, builtin_skills_dir=builtin)
+    entries = loader.list_skills(filter_unavailable=False)
+    names = {entry["name"] for entry in entries}
+    assert names == {"ok"}
+    assert entries[0]["path"] == str(ok_path)
+
+
+def test_list_skills_workspace_shadows_builtin_same_name(tmp_path: Path) -> None:
+    workspace = tmp_path / "ws"
+    ws_skills = workspace / "skills"
+    ws_skills.mkdir(parents=True)
+    ws_path = _write_skill(ws_skills, "dup", body="# Workspace wins")
+
+    builtin = tmp_path / "builtin"
+    _write_skill(builtin, "dup", body="# Builtin")
+
+    loader = SkillsLoader(workspace, builtin_skills_dir=builtin)
+    entries = loader.list_skills(filter_unavailable=False)
+    assert len(entries) == 1
+    assert entries[0]["source"] == "workspace"
+    assert entries[0]["path"] == str(ws_path)
+
+
+def test_list_skills_merges_workspace_and_builtin(tmp_path: Path) -> None:
+    workspace = tmp_path / "ws"
+    ws_skills = workspace / "skills"
+    ws_skills.mkdir(parents=True)
+    ws_path = _write_skill(ws_skills, "ws_only", body="# W")
+    builtin = tmp_path / "builtin"
+    bi_path = _write_skill(builtin, "bi_only", body="# B")
+
+    loader = SkillsLoader(workspace, builtin_skills_dir=builtin)
+    entries = sorted(loader.list_skills(filter_unavailable=False), key=lambda item: item["name"])
+    assert entries == [
+        {"name": "bi_only", "path": str(bi_path), "source": "builtin"},
+        {"name": "ws_only", "path": str(ws_path), "source": "workspace"},
+    ]
+
+
+def test_list_skills_builtin_omitted_when_dir_missing(tmp_path: Path) -> None:
+    workspace = tmp_path / "ws"
+    ws_skills = workspace / "skills"
+    ws_skills.mkdir(parents=True)
+    ws_path = _write_skill(ws_skills, "solo", body="# S")
+    missing_builtin = tmp_path / "no_such_builtin"
+
+    loader = SkillsLoader(workspace, builtin_skills_dir=missing_builtin)
+    entries = loader.list_skills(filter_unavailable=False)
+    assert entries == [{"name": "solo", "path": str(ws_path), "source": "workspace"}]
+
+
+def test_list_skills_filter_unavailable_excludes_unmet_bin_requirement(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    workspace = tmp_path / "ws"
+    skills_root = workspace / "skills"
+    skills_root.mkdir(parents=True)
+    _write_skill(
+        skills_root,
+        "needs_bin",
+        metadata_json={"requires": {"bins": ["nanobot_test_fake_binary"]}},
+    )
+    builtin = tmp_path / "builtin"
+    builtin.mkdir()
+
+    def fake_which(cmd: str) -> str | None:
+        if cmd == "nanobot_test_fake_binary":
+            return None
+        return "/usr/bin/true"
+
+    monkeypatch.setattr("nanobot.agent.skills.shutil.which", fake_which)
+
+    loader = SkillsLoader(workspace, builtin_skills_dir=builtin)
+    assert loader.list_skills(filter_unavailable=True) == []
+
+
+def test_list_skills_filter_unavailable_includes_when_bin_requirement_met(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    workspace = tmp_path / "ws"
+    skills_root = workspace / "skills"
+    skills_root.mkdir(parents=True)
+    skill_path = _write_skill(
+        skills_root,
+        "has_bin",
+        metadata_json={"requires": {"bins": ["nanobot_test_fake_binary"]}},
+    )
+    builtin = tmp_path / "builtin"
+    builtin.mkdir()
+
+    def fake_which(cmd: str) -> str | None:
+        if cmd == "nanobot_test_fake_binary":
+            return "/fake/nanobot_test_fake_binary"
+        return None
+
+    monkeypatch.setattr("nanobot.agent.skills.shutil.which", fake_which)
+
+    loader = SkillsLoader(workspace, builtin_skills_dir=builtin)
+    entries = loader.list_skills(filter_unavailable=True)
+    assert entries == [
+        {"name": "has_bin", "path": str(skill_path), "source": "workspace"},
+    ]
+
+
+def test_list_skills_filter_unavailable_false_keeps_unmet_requirements(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    workspace = tmp_path / "ws"
+    skills_root = workspace / "skills"
+    skills_root.mkdir(parents=True)
+    skill_path = _write_skill(
+        skills_root,
+        "blocked",
+        metadata_json={"requires": {"bins": ["nanobot_test_fake_binary"]}},
+    )
+    builtin = tmp_path / "builtin"
+    builtin.mkdir()
+
+    monkeypatch.setattr("nanobot.agent.skills.shutil.which", lambda _cmd: None)
+
+    loader = SkillsLoader(workspace, builtin_skills_dir=builtin)
+    entries = loader.list_skills(filter_unavailable=False)
+    assert entries == [
+        {"name": "blocked", "path": str(skill_path), "source": "workspace"},
+    ]
+
+
+def test_list_skills_filter_unavailable_excludes_unmet_env_requirement(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    workspace = tmp_path / "ws"
+    skills_root = workspace / "skills"
+    skills_root.mkdir(parents=True)
+    _write_skill(
+        skills_root,
+        "needs_env",
+        metadata_json={"requires": {"env": ["NANOBOT_SKILLS_TEST_ENV_VAR"]}},
+    )
+    builtin = tmp_path / "builtin"
+    builtin.mkdir()
+
+    monkeypatch.delenv("NANOBOT_SKILLS_TEST_ENV_VAR", raising=False)
+
+    loader = SkillsLoader(workspace, builtin_skills_dir=builtin)
+    assert loader.list_skills(filter_unavailable=True) == []
+
+
+def test_list_skills_openclaw_metadata_parsed_for_requirements(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    workspace = tmp_path / "ws"
+    skills_root = workspace / "skills"
+    skills_root.mkdir(parents=True)
+    skill_dir = skills_root / "openclaw_skill"
+    skill_dir.mkdir(parents=True)
+    skill_path = skill_dir / "SKILL.md"
+    oc_payload = json.dumps({"openclaw": {"requires": {"bins": ["nanobot_oc_bin"]}}}, separators=(",", ":"))
+    skill_path.write_text(
+        "\n".join(["---", f"metadata: {oc_payload}", "---", "", "# OC"]),
+        encoding="utf-8",
+    )
+    builtin = tmp_path / "builtin"
+    builtin.mkdir()
+
+    monkeypatch.setattr("nanobot.agent.skills.shutil.which", lambda _cmd: None)
+
+    loader = SkillsLoader(workspace, builtin_skills_dir=builtin)
+    assert loader.list_skills(filter_unavailable=True) == []
+
+    monkeypatch.setattr(
+        "nanobot.agent.skills.shutil.which",
+        lambda cmd: "/x" if cmd == "nanobot_oc_bin" else None,
+    )
+    entries = loader.list_skills(filter_unavailable=True)
+    assert entries == [
+        {"name": "openclaw_skill", "path": str(skill_path), "source": "workspace"},
+    ]

tests/tools/test_tool_validation.py

@@ -1,3 +1,6 @@
+import shlex
+import subprocess
+import sys
 from typing import Any
 
 from nanobot.agent.tools import (
@@ -546,10 +549,15 @@ async def test_exec_head_tail_truncation() -> None:
     """Long output should preserve both head and tail."""
     tool = ExecTool()
     # Generate output that exceeds _MAX_OUTPUT (10_000 chars)
-    # Use python to generate output to avoid command line length limits
+    # Use current interpreter (PATH may not have `python`). ExecTool uses
-    result = await tool.execute(
+    # create_subprocess_shell: POSIX needs shlex.quote; Windows uses cmd.exe
-        command="python -c \"print('A' * 6000 + '\\n' + 'B' * 6000)\""
+    # rules, so list2cmdline is appropriate there.
-    )
+    script = "print('A' * 6000 + '\\n' + 'B' * 6000)"
+    if sys.platform == "win32":
+        command = subprocess.list2cmdline([sys.executable, "-c", script])
+    else:
+        command = f"{shlex.quote(sys.executable)} -c {shlex.quote(script)}"
+    result = await tool.execute(command=command)
     assert "chars truncated" in result
     # Head portion should start with As
     assert result.startswith("A")