diff --git a/nanobot/agent/tools/web.py b/nanobot/agent/tools/web.py
index 35c5c3b..89c9a40 100644
--- a/nanobot/agent/tools/web.py
+++ b/nanobot/agent/tools/web.py
@@ -60,7 +60,7 @@ class WebSearchTool(Tool):
 
     def __init__(
         self,
-        provider: str = "brave",
+        provider: str | None = None,
         api_key: str | None = None,
         base_url: str | None = None,
         max_results: int = 5,
@@ -87,7 +87,11 @@ class WebSearchTool(Tool):
     @property
     def base_url(self) -> str:
         """Resolve SearXNG base URL at call time so env/config changes are picked up."""
-        return (self._init_base_url or os.environ.get("SEARXNG_BASE_URL", "")).strip()
+        return (
+            self._init_base_url
+            or os.environ.get("WEB_SEARCH_BASE_URL", "")
+            or os.environ.get("SEARXNG_BASE_URL", "")
+        ).strip()
 
     async def execute(self, query: str, count: int | None = None, **kwargs: Any) -> str:
         provider = self.provider
@@ -134,7 +138,7 @@ class WebSearchTool(Tool):
         if not self.base_url:
             return (
                 "Error: SearXNG base URL not configured. Set tools.web.search.baseUrl "
-                'in ~/.nanobot/config.json (or export SEARXNG_BASE_URL), e.g. "http://localhost:8080".'
+                'in ~/.nanobot/config.json (or export WEB_SEARCH_BASE_URL), e.g. "http://localhost:8080".'
             )
 
         is_valid, error_msg = _validate_url(self.base_url)
diff --git a/tests/test_web_tools.py b/tests/test_web_tools.py
index 2d7c8cd..5c48e20 100644
--- a/tests/test_web_tools.py
+++ b/tests/test_web_tools.py
@@ -148,3 +148,57 @@ def test_web_search_config_accepts_searxng_fields() -> None:
     assert config.tools.web.search.provider == "searxng"
     assert config.tools.web.search.base_url == "http://localhost:8080"
     assert config.tools.web.search.max_results == 7
+
+
+@pytest.mark.asyncio
+async def test_web_search_tool_uses_env_provider_and_base_url(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    calls: list[dict[str, Any]] = []
+    payload = {
+        "results": [
+            {
+                "title": "Nanobot Env",
+                "url": "https://example.com/env",
+                "content": "Resolved from environment variables.",
+            }
+        ]
+    }
+
+    class _FakeAsyncClient:
+        def __init__(self, *args: Any, **kwargs: Any) -> None:
+            self.proxy = kwargs.get("proxy")
+
+        async def __aenter__(self) -> "_FakeAsyncClient":
+            return self
+
+        async def __aexit__(self, exc_type, exc, tb) -> None:
+            return None
+
+        async def get(
+            self,
+            url: str,
+            *,
+            params: dict[str, Any] | None = None,
+            headers: dict[str, str] | None = None,
+            timeout: float | None = None,
+        ) -> _FakeResponse:
+            calls.append({"url": url, "params": params, "headers": headers, "timeout": timeout})
+            return _FakeResponse(payload)
+
+    monkeypatch.setattr(web_module.httpx, "AsyncClient", _FakeAsyncClient)
+    monkeypatch.setenv("WEB_SEARCH_PROVIDER", "searxng")
+    monkeypatch.setenv("WEB_SEARCH_BASE_URL", "http://localhost:9090")
+
+    tool = WebSearchTool()
+    result = await tool.execute(query="nanobot", count=2)
+
+    assert "Nanobot Env" in result
+    assert calls == [
+        {
+            "url": "http://localhost:9090/search",
+            "params": {"q": "nanobot", "format": "json"},
+            "headers": {"Accept": "application/json"},
+            "timeout": 10.0,
+        }
+    ]