fix(plugins): defer tool imports for disabled plugins

src/openharness/plugins/loader.py

@@ -138,7 +138,7 @@ def load_plugin(path: Path, enabled_plugins: dict[str, bool]) -> LoadedPlugin |
     skills = _load_plugin_skills(path / manifest.skills_dir)
     commands = _load_plugin_commands(path, manifest)
     agents = _load_plugin_agents(path, manifest)
-    tools = _load_plugin_tools(path, manifest)
+    tools = _load_plugin_tools(path, manifest) if enabled else []
     hooks = _load_plugin_hooks(path / manifest.hooks_file)
     hooks_dir_file = path / "hooks" / "hooks.json"
     if not hooks and hooks_dir_file.exists():

src/openharness/plugins/types.py

@@ -4,12 +4,16 @@ from __future__ import annotations
 
 from dataclasses import dataclass, field
 from pathlib import Path
+from typing import TYPE_CHECKING
 
 from openharness.coordinator.agent_definitions import AgentDefinition
 from openharness.mcp.types import McpServerConfig
 from openharness.plugins.schemas import PluginManifest
 from openharness.skills.types import SkillDefinition
 
+if TYPE_CHECKING:
+    from openharness.tools.base import BaseTool
+
 
 @dataclass(frozen=True)
 class PluginCommandDefinition:
@@ -42,7 +46,7 @@ class LoadedPlugin:
     skills: list[SkillDefinition] = field(default_factory=list)
     commands: list[PluginCommandDefinition] = field(default_factory=list)
     agents: list[AgentDefinition] = field(default_factory=list)
-    tools: list = field(default_factory=list)
+    tools: list[BaseTool] = field(default_factory=list)
     hooks: dict[str, list] = field(default_factory=dict)
     mcp_servers: dict[str, McpServerConfig] = field(default_factory=dict)
 

tests/test_plugins/test_loader.py

@@ -71,6 +71,38 @@ def _write_plugin(root: Path) -> None:
     )
 
 
+def _write_tool_plugin(root: Path, *, enabled_by_default: bool = True) -> Path:
+    plugin_dir = root / "tool-plugin"
+    tools_dir = plugin_dir / "tools"
+    tools_dir.mkdir(parents=True)
+    (plugin_dir / "plugin.json").write_text(
+        json.dumps(
+            {
+                "name": "tool-plugin",
+                "version": "1.0.0",
+                "description": "Example tool plugin",
+                "enabled_by_default": enabled_by_default,
+            }
+        ),
+        encoding="utf-8",
+    )
+    (tools_dir / "echo_tool.py").write_text(
+        "from pydantic import BaseModel\n"
+        "from openharness.tools.base import BaseTool, ToolExecutionContext, ToolResult\n\n"
+        "class EchoArgs(BaseModel):\n"
+        "    text: str = 'hello'\n\n"
+        "class EchoTool(BaseTool):\n"
+        "    name = 'plugin_echo'\n"
+        "    description = 'Echo from plugin tool'\n"
+        "    input_model = EchoArgs\n\n"
+        "    async def execute(self, arguments: EchoArgs, context: ToolExecutionContext) -> ToolResult:\n"
+        "        del context\n"
+        "        return ToolResult(output=arguments.text)\n",
+        encoding="utf-8",
+    )
+    return plugin_dir
+
+
 def test_load_plugins_from_project_dir(tmp_path: Path, monkeypatch):
     monkeypatch.setenv("OPENHARNESS_CONFIG_DIR", str(tmp_path / "config"))
     project = tmp_path / "repo"
@@ -148,3 +180,42 @@ def test_user_plugins_still_load_when_project_plugins_are_disabled(tmp_path: Pat
 
     assert len(plugins) == 1
     assert plugins[0].manifest.name == "example"
+
+
+def test_enabled_plugin_tools_are_loaded(tmp_path: Path, monkeypatch):
+    monkeypatch.setenv("OPENHARNESS_CONFIG_DIR", str(tmp_path / "config"))
+    project = tmp_path / "repo"
+    plugins_root = project / ".openharness" / "plugins"
+    plugins_root.mkdir(parents=True)
+    _write_tool_plugin(plugins_root, enabled_by_default=True)
+
+    plugins = load_plugins(Settings(allow_project_plugins=True), project)
+
+    assert len(plugins) == 1
+    plugin = plugins[0]
+    assert plugin.enabled is True
+    assert [tool.name for tool in plugin.tools] == ["plugin_echo"]
+
+
+def test_disabled_plugin_tools_are_not_imported(tmp_path: Path, monkeypatch):
+    monkeypatch.setenv("OPENHARNESS_CONFIG_DIR", str(tmp_path / "config"))
+    project = tmp_path / "repo"
+    plugins_root = project / ".openharness" / "plugins"
+    plugins_root.mkdir(parents=True)
+    plugin_dir = _write_tool_plugin(plugins_root, enabled_by_default=False)
+    marker = tmp_path / "tool-imported.txt"
+    tool_file = plugin_dir / "tools" / "echo_tool.py"
+    tool_file.write_text(
+        f"from pathlib import Path\n"
+        f"Path({str(marker)!r}).write_text('loaded', encoding='utf-8')\n"
+        + tool_file.read_text(encoding="utf-8"),
+        encoding="utf-8",
+    )
+
+    plugins = load_plugins(Settings(allow_project_plugins=True), project)
+
+    assert len(plugins) == 1
+    plugin = plugins[0]
+    assert plugin.enabled is False
+    assert plugin.tools == []
+    assert not marker.exists()

tests/test_ui/test_runtime_plugin_tools.py

@@ -0,0 +1,67 @@
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+import pytest
+
+from openharness.ui.runtime import build_runtime, close_runtime
+
+
+class _StaticApiClient:
+    async def stream_message(self, request):
+        del request
+        if False:
+            yield None
+
+
+def _write_tool_plugin(plugins_root: Path) -> None:
+    plugin_dir = plugins_root / "tool-plugin"
+    tools_dir = plugin_dir / "tools"
+    tools_dir.mkdir(parents=True)
+    (plugin_dir / "plugin.json").write_text(
+        json.dumps(
+            {
+                "name": "tool-plugin",
+                "version": "1.0.0",
+                "description": "Runtime tool plugin",
+                "enabled_by_default": True,
+            }
+        ),
+        encoding="utf-8",
+    )
+    (tools_dir / "echo_tool.py").write_text(
+        "from pydantic import BaseModel\n"
+        "from openharness.tools.base import BaseTool, ToolExecutionContext, ToolResult\n\n"
+        "class EchoArgs(BaseModel):\n"
+        "    text: str = 'hello'\n\n"
+        "class EchoTool(BaseTool):\n"
+        "    name = 'plugin_echo'\n"
+        "    description = 'Echo from plugin tool'\n"
+        "    input_model = EchoArgs\n\n"
+        "    async def execute(self, arguments: EchoArgs, context: ToolExecutionContext) -> ToolResult:\n"
+        "        del context\n"
+        "        return ToolResult(output=arguments.text)\n",
+        encoding="utf-8",
+    )
+
+
+@pytest.mark.asyncio
+async def test_build_runtime_registers_enabled_plugin_tools(tmp_path: Path, monkeypatch):
+    monkeypatch.setenv("OPENHARNESS_CONFIG_DIR", str(tmp_path / "config"))
+    project = tmp_path / "repo"
+    plugins_root = project / ".openharness" / "plugins"
+    plugins_root.mkdir(parents=True)
+    _write_tool_plugin(plugins_root)
+
+    from openharness.config.settings import Settings
+
+    monkeypatch.setattr("openharness.ui.runtime.load_settings", lambda: Settings(allow_project_plugins=True))
+
+    bundle = await build_runtime(cwd=str(project), api_client=_StaticApiClient())
+    try:
+        tool = bundle.tool_registry.get("plugin_echo")
+        assert tool is not None
+        assert tool.description == "Echo from plugin tool"
+    finally:
+        await close_runtime(bundle)