diff --git a/ra_aid/agent_utils.py b/ra_aid/agent_utils.py
index 8b1708b..a170519 100644
--- a/ra_aid/agent_utils.py
+++ b/ra_aid/agent_utils.py
@@ -236,11 +236,11 @@ def is_anthropic_claude(config: Dict[str, Any]) -> bool:
     """
     provider = config.get("provider", "")
     model_name = config.get("model", "")
-    return (
-        provider.lower() == "anthropic"
-        and model_name
-        and "claude" in model_name.lower()
+    result = (
+        (provider.lower() == "anthropic" and model_name and "claude" in model_name.lower())
+        or (provider.lower() == "openrouter" and model_name.lower().startswith("anthropic/claude-"))
     )
+    return result
 
 
 def create_agent(
diff --git a/tests/ra_aid/test_agent_utils.py b/tests/ra_aid/test_agent_utils.py
index 5346921..a9eb515 100644
--- a/tests/ra_aid/test_agent_utils.py
+++ b/tests/ra_aid/test_agent_utils.py
@@ -12,6 +12,7 @@ from ra_aid.agent_utils import (
     AgentState,
     create_agent,
     get_model_token_limit,
+    is_anthropic_claude,
     state_modifier,
 )
 from ra_aid.models_params import DEFAULT_TOKEN_LIMIT, models_params
@@ -401,3 +402,22 @@ def test_handle_api_error_retry(monkeypatch):
     monkeypatch.setattr(time, "sleep", lambda s: None)
     # Should not raise error when attempt is lower than max retries
     _handle_api_error(Exception("error code 429"), 0, 5, 1)
+
+
+def test_is_anthropic_claude():
+    """Test is_anthropic_claude function with various configurations."""
+    # Test Anthropic provider cases
+    assert is_anthropic_claude({"provider": "anthropic", "model": "claude-2"})
+    assert is_anthropic_claude({"provider": "ANTHROPIC", "model": "claude-instant"})
+    assert not is_anthropic_claude({"provider": "anthropic", "model": "gpt-4"})
+    
+    # Test OpenRouter provider cases
+    assert is_anthropic_claude({"provider": "openrouter", "model": "anthropic/claude-2"})
+    assert is_anthropic_claude({"provider": "openrouter", "model": "anthropic/claude-instant"})
+    assert not is_anthropic_claude({"provider": "openrouter", "model": "openai/gpt-4"})
+    
+    # Test edge cases
+    assert not is_anthropic_claude({})  # Empty config
+    assert not is_anthropic_claude({"provider": "anthropic"})  # Missing model
+    assert not is_anthropic_claude({"model": "claude-2"})  # Missing provider
+    assert not is_anthropic_claude({"provider": "other", "model": "claude-2"})  # Wrong provider