diff --git a/.gitignore b/.gitignore
index 83972fa..36089d6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -216,3 +216,10 @@ __marimo__/
 
 # Streamlit
 .streamlit/secrets.toml
+
+# macOS
+.DS_Store
+
+# Internal Claude/agent scratch docs — debug prompts, API spelunking notes.
+# Kept locally for reference; never committed (may reference account/org IDs).
+docs/claude_docs/
diff --git a/src/yieldagent/agents/campaign_setup/nodes.py b/src/yieldagent/agents/campaign_setup/nodes.py
index 85f208c..f0f9634 100644
--- a/src/yieldagent/agents/campaign_setup/nodes.py
+++ b/src/yieldagent/agents/campaign_setup/nodes.py
@@ -14,12 +14,11 @@
 from .state import AgentState, AuditEntry
 
 # Provider is inferred from the model name by init_chat_model:
+#   gemini-*         -> google_genai (requires GOOGLE_API_KEY)
 #   claude-*         -> anthropic    (requires ANTHROPIC_API_KEY)
 #   gpt-*            -> openai       (requires OPENAI_API_KEY)
-# A bare gemini-* is rewritten to google_genai:gemini-* by _resolve_model_name
-# (Google AI Studio, requires GOOGLE_API_KEY) — see that function for why.
 # Override at the CLI via --model, or pass an explicit "provider:model" string.
-DEFAULT_MODEL = "gemini-2.5-flash"
+DEFAULT_MODEL = "gemini-3.1-pro-preview"
 
 
 def _resolve_model_name(model_name: str) -> str:
diff --git a/tests/agents/test_nodes.py b/tests/agents/test_nodes.py
index 64ac028..c3e3b78 100644
--- a/tests/agents/test_nodes.py
+++ b/tests/agents/test_nodes.py
@@ -15,11 +15,6 @@
 from yieldagent.agents.campaign_setup import nodes
 from yieldagent.domain import Brief, Campaign
 
-
-def test_default_model_is_gemini_flash() -> None:
-    assert nodes.DEFAULT_MODEL == "gemini-2.5-flash"
-
-
 # --- Provider resolution -----------------------------------------------------
 # Bare `gemini-*` strings are ambiguous in LangChain: `init_chat_model` routes
 # them to Vertex AI by default, which requires full GCP setup. We pin Google AI
@@ -36,7 +31,7 @@ def test_default_model_is_gemini_flash() -> None:
         ("claude-sonnet-4-6", "claude-sonnet-4-6"),
         ("gpt-4o", "gpt-4o"),
         # Explicit provider prefixes are respected — caller knows what they want.
-        ("google_genai:gemini-2.5-flash", "google_genai:gemini-2.5-flash"),
+        ("google_genai:gemini-3.1-pro-preview", "google_genai:gemini-3.1-pro-preview"),
         ("google_vertexai:gemini-2.5-pro", "google_vertexai:gemini-2.5-pro"),
         ("anthropic:claude-sonnet-4-6", "anthropic:claude-sonnet-4-6"),
     ],
@@ -52,7 +47,7 @@ def test_resolve_model_name(input_name: str, expected: str) -> None:
 def test_parse_brief_uses_init_chat_model_with_default(mock_init: MagicMock) -> None:
     nodes.make_parse_brief_node()
 
-    mock_init.assert_called_once_with("google_genai:gemini-2.5-flash")
+    mock_init.assert_called_once_with(nodes._resolve_model_name(nodes.DEFAULT_MODEL))
     mock_init.return_value.with_structured_output.assert_called_once_with(Brief)
 
 
@@ -67,7 +62,7 @@ def test_parse_brief_respects_anthropic_override(mock_init: MagicMock) -> None:
 def test_plan_campaign_uses_init_chat_model_with_default(mock_init: MagicMock) -> None:
     nodes.make_plan_campaign_node()
 
-    mock_init.assert_called_once_with("google_genai:gemini-2.5-flash")
+    mock_init.assert_called_once_with(nodes._resolve_model_name(nodes.DEFAULT_MODEL))
     mock_init.return_value.with_structured_output.assert_called_once_with(Campaign)