feat(tools): add SkillSearchTool and improve skill_install workflow

Add skill_search tool so agent can search for skills before installing.
Update skill_install description to guide LLM to search first.
Update system prompt to use skill_search -> skill_install flow.
This fixes the issue where agent returns empty when asked to find a skill.

src/agentkit/server/app.py

@@ -21,6 +21,7 @@ from agentkit.skills.base import Skill
 from agentkit.skills.registry import SkillRegistry
 from agentkit.tools.registry import ToolRegistry
 from agentkit.tools.skill_install import SkillInstallTool
+from agentkit.tools.skill_search import SkillSearchTool
 from agentkit.server.config import ServerConfig, load_dotenv
 from agentkit.server.routes import (
     agents,
@@ -174,9 +175,8 @@ async def lifespan(app: FastAPI):
             "中文内容优先使用 baidu_search 工具，英文/国际内容使用 web_search。"
             "在能够搜索到真相的情况下，绝不猜测或编造答案。"
             "始终优先搜索而不是给出可能不正确的信息。\n\n"
-            "技能安装：当需要安装技能时，使用 skill_install 工具，不要用 shell 执行 npm install。"
+            "技能安装：当需要查找或安装技能时，先用 skill_search 搜索确认技能名称和来源，"
-            "skill_install 的 source 参数格式为 owner/repo@skill，例如 vercel-labs/skills@find-skills。"
+            "再用 skill_install 安装。不要用 shell 执行 npm install 或 npx skills install。"
-            "如果不知道完整 source，先用 shell 执行 `npx skills search <name>` 搜索。"
         )
         effective_system_prompt = memory_store.build_system_prompt(memory_snapshot, base_prompt)
 
@@ -227,6 +227,7 @@ async def lifespan(app: FastAPI):
                     tool_registry=app.state.tool_registry,
                 )
             )
+            agent._tool_registry.register(SkillSearchTool())
             agent._tool_registry.register(BaiduSearchTool())
             agent._tool_registry.register(WebSearchTool(**search_api_keys))
             agent._tool_registry.register(WebCrawlTool())

src/agentkit/tools/skill_install.py

@@ -24,7 +24,11 @@ class SkillInstallTool(Tool):
     def __init__(
         self,
         name: str = "skill_install",
-        description: str = "安装 Agent 技能包。使用 npx skills install 安装指定技能，不要用 npm install。",
+        description: str = (
+            "安装 Agent 技能包。使用 npx skills install 安装指定技能，不要用 npm install。"
+            "重要：安装前应先用 skill_search 工具搜索确认技能名称和来源(source)。"
+            "如果用户只提供了模糊名称，先用 skill_search 搜索，再根据搜索结果安装。"
+        ),
         input_schema: dict[str, Any] | None = None,
         output_schema: dict[str, Any] | None = None,
         version: str = "1.0.0",

src/agentkit/tools/skill_search.py

@@ -0,0 +1,141 @@
+"""SkillSearchTool - Agent 可调用的技能搜索工具"""
+
+import asyncio
+import logging
+from typing import Any
+
+from agentkit.tools.base import Tool
+
+logger = logging.getLogger(__name__)
+
+
+class SkillSearchTool(Tool):
+    """技能搜索工具
+
+    让 Agent 可以搜索可用的技能包，在安装之前先确认技能是否存在。
+    使用 `npx skills search <keyword>` 搜索可用技能。
+
+    Usage:
+        tool = SkillSearchTool()
+        result = await tool.execute(keyword="ppt")
+    """
+
+    def __init__(
+        self,
+        name: str = "skill_search",
+        description: str = (
+            "搜索可用的 Agent 技能包。在安装技能之前，应先使用此工具搜索确认技能名称和来源。"
+            "返回匹配的技能列表，包含名称、描述和安装来源。"
+        ),
+        input_schema: dict[str, Any] | None = None,
+        output_schema: dict[str, Any] | None = None,
+        version: str = "1.0.0",
+        tags: list[str] | None = None,
+    ):
+        schema = input_schema or {
+            "type": "object",
+            "properties": {
+                "keyword": {
+                    "type": "string",
+                    "description": "搜索关键词，如 ppt、code-review、find-skills",
+                },
+            },
+            "required": ["keyword"],
+        }
+        super().__init__(
+            name=name,
+            description=description,
+            input_schema=schema,
+            output_schema=output_schema,
+            version=version,
+            tags=tags or ["skill", "search"],
+        )
+
+    async def execute(self, **kwargs) -> dict:
+        keyword = kwargs.get("keyword", "").strip()
+
+        if not keyword:
+            return {
+                "output": "错误: 必须提供 keyword 参数",
+                "exit_code": 1,
+                "is_error": True,
+            }
+
+        try:
+            proc = await asyncio.create_subprocess_exec(
+                "npx", "skills@latest", "search", keyword,
+                stdout=asyncio.subprocess.PIPE,
+                stderr=asyncio.subprocess.PIPE,
+            )
+            stdout, stderr = await asyncio.wait_for(proc.communicate(), timeout=60)
+            output = stdout.decode("utf-8", errors="replace")
+            error_output = stderr.decode("utf-8", errors="replace")
+
+            if output.strip():
+                # Parse and format the search results
+                results = self._format_search_results(output, keyword)
+                return {
+                    "output": results,
+                    "exit_code": 0,
+                    "is_error": False,
+                }
+            elif error_output.strip():
+                # Some versions output to stderr
+                results = self._format_search_results(error_output, keyword)
+                return {
+                    "output": results,
+                    "exit_code": 0,
+                    "is_error": False,
+                }
+            else:
+                return {
+                    "output": (
+                        f"未找到与 '{keyword}' 匹配的技能。\n\n"
+                        "建议：\n"
+                        "1. 尝试不同的关键词搜索\n"
+                        "2. 检查技能名称拼写\n"
+                        "3. 访问 https://github.com/topics/agent-skills 浏览可用技能"
+                    ),
+                    "exit_code": 0,
+                    "is_error": False,
+                }
+        except asyncio.TimeoutError:
+            return {
+                "output": f"搜索技能 '{keyword}' 超时（60s），请稍后重试",
+                "exit_code": -1,
+                "is_error": True,
+            }
+        except FileNotFoundError:
+            return {
+                "output": (
+                    "npx 命令未找到，请确保 Node.js 已安装。\n"
+                    "安装方式: https://nodejs.org/"
+                ),
+                "exit_code": -1,
+                "is_error": True,
+            }
+        except Exception as e:
+            return {
+                "output": f"搜索技能 '{keyword}' 时发生异常: {e}",
+                "exit_code": -1,
+                "is_error": True,
+            }
+
+    @staticmethod
+    def _format_search_results(raw_output: str, keyword: str) -> str:
+        """Format raw npx skills search output into a readable result."""
+        # Clean up ANSI escape codes
+        import re
+        clean = re.sub(r"\x1b\[[0-9;]*m", "", raw_output)
+
+        if not clean.strip():
+            return (
+                f"未找到与 '{keyword}' 匹配的技能。\n\n"
+                "建议：\n"
+                "1. 尝试不同的关键词搜索\n"
+                "2. 检查技能名称拼写\n"
+                "3. 访问 https://github.com/topics/agent-skills 浏览可用技能"
+            )
+
+        # Return the cleaned output with a helpful header
+        return f"搜索 '{keyword}' 的结果：\n\n{clean.strip()}"