diff --git a/researchers/web/agent.py b/researchers/web/agent.py
index 391e106..b3c0d1b 100644
--- a/researchers/web/agent.py
+++ b/researchers/web/agent.py
@@ -167,7 +167,7 @@ class WebResearcher:
         self,
         anthropic_api_key: str,
         tavily_api_key: str,
-        model_id: str = "claude-sonnet-4-5-20250514",
+        model_id: str = "claude-sonnet-4-6",
         trace_dir: Optional[str] = None,
     ):
         self.client = Anthropic(api_key=anthropic_api_key)
diff --git a/researchers/web/server.py b/researchers/web/server.py
index ac90bf5..bce016c 100644
--- a/researchers/web/server.py
+++ b/researchers/web/server.py
@@ -40,7 +40,7 @@ def _get_researcher() -> WebResearcher:
     return WebResearcher(
         anthropic_api_key=_read_secret("ANTHROPIC_API_KEY"),
         tavily_api_key=_read_secret("TAVILY_API_KEY"),
-        model_id=os.environ.get("MARCHWARDEN_MODEL", "claude-sonnet-4-5-20250514"),
+        model_id=os.environ.get("MARCHWARDEN_MODEL", "claude-sonnet-4-6"),
     )