feat(web): add Keenable search provider

Add Keenable (https://keenable.ai) as a web_search backend, modeled on
the existing httpx-based providers. Unlike key-gated providers, Keenable
has a no-login free tier, so it resolves to itself even without an API
key instead of falling back to DuckDuckGo; the X-API-Key header is only
sent when a key is configured (config api_key or KEENABLE_API_KEY env).

Maps result snippet (falling back to description) into the shared
content field. Covered by tests for keyed/anonymous search and the
no-fallback concurrency behavior.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

nanobot/agent/tools/web.py

@@ -317,6 +317,8 @@ class WebSearchTool(Tool):
                 or os.environ.get("WEB_SEARCH_API_KEY", "")
             )
             return "volcengine" if api_key else "duckduckgo"
+        if provider == "keenable":
+            return "keenable"  # free tier works without a key; never fall back
         return provider
 
     @property
@@ -371,6 +373,8 @@ class WebSearchTool(Tool):
                 n,
                 freshness=kwargs.get("freshness", "noLimit"),
             )
+        elif provider == "keenable":
+            return await self._search_keenable(query, n)
         else:
             return f"Error: unknown search provider '{provider}'"
 
@@ -484,6 +488,33 @@ class WebSearchTool(Tool):
         except Exception as e:
             return f"Error: {e}"
 
+    async def _search_keenable(self, query: str, n: int) -> str:
+        # Keenable has a no-login free tier, so an API key is optional.
+        api_key = self.config.api_key or os.environ.get("KEENABLE_API_KEY", "")
+        headers = {"Content-Type": "application/json", "User-Agent": self.user_agent}
+        if api_key:
+            headers["X-API-Key"] = api_key
+        try:
+            async with httpx.AsyncClient(proxy=self.proxy) as client:
+                r = await client.post(
+                    "https://api.keenable.ai/v1/search",
+                    headers=headers,
+                    json={"query": query},
+                    timeout=15.0,
+                )
+                r.raise_for_status()
+            items = [
+                {
+                    "title": x.get("title", ""),
+                    "url": x.get("url", ""),
+                    "content": x.get("snippet") or x.get("description", ""),
+                }
+                for x in r.json().get("results", [])
+            ]
+            return _format_results(query, items, n)
+        except Exception as e:
+            return f"Error: {e}"
+
     async def _search_searxng(self, query: str, n: int) -> str:
         base_url = (self.config.base_url or os.environ.get("SEARXNG_BASE_URL", "")).strip()
         if not base_url:

tests/tools/test_web_search_tool.py

@@ -131,6 +131,54 @@ async def test_tavily_search(monkeypatch):
     assert "https://openclaw.io" in result
 
 
+def test_keenable_without_api_key_stays_on_provider(monkeypatch):
+    # Free tier needs no key, so Keenable must not fall back to DuckDuckGo.
+    monkeypatch.delenv("KEENABLE_API_KEY", raising=False)
+    tool = _tool(provider="keenable", api_key="")
+    assert tool.exclusive is False
+    assert tool.concurrency_safe is True
+
+
+@pytest.mark.asyncio
+async def test_keenable_search(monkeypatch):
+    async def mock_post(self, url, **kw):
+        assert "keenable" in url
+        assert kw["headers"]["X-API-Key"] == "keen-key"
+        assert kw["headers"]["User-Agent"] == "nanobot-search-test"
+        return _response(json={
+            "results": [{
+                "title": "Keen",
+                "url": "https://keenable.ai",
+                "description": "short",
+                "snippet": "longer excerpt",
+            }]
+        })
+
+    monkeypatch.setattr(httpx.AsyncClient, "post", mock_post)
+    tool = _tool(provider="keenable", api_key="keen-key", user_agent="nanobot-search-test")
+    result = await tool.execute(query="keenable", count=1)
+    assert "Keen" in result
+    assert "https://keenable.ai" in result
+    assert "longer excerpt" in result  # snippet preferred over description
+
+
+@pytest.mark.asyncio
+async def test_keenable_search_without_key_omits_header(monkeypatch):
+    monkeypatch.delenv("KEENABLE_API_KEY", raising=False)
+
+    async def mock_post(self, url, **kw):
+        assert "keenable" in url
+        assert "X-API-Key" not in kw["headers"]
+        return _response(json={
+            "results": [{"title": "Anon", "url": "https://keenable.ai", "description": "ok"}]
+        })
+
+    monkeypatch.setattr(httpx.AsyncClient, "post", mock_post)
+    tool = _tool(provider="keenable", api_key="")
+    result = await tool.execute(query="keenable", count=1)
+    assert "Anon" in result  # description used when snippet absent
+
+
 @pytest.mark.asyncio
 async def test_bocha_search(monkeypatch):
     async def mock_post(self, url, **kw):