From f1baceb8ab1c84fa81dc8cb0c1c3e6864698b23d Mon Sep 17 00:00:00 2001
From: Johannes du Plessis <johannes@langchain.dev>
Date: Thu, 4 Jun 2026 17:38:54 -0700
Subject: [PATCH] feat: add Gemini 3.5 Flash provider (#1420)

---
 agent/dashboard/options.py | 23 +++++++++++++++++++++--
 agent/utils/model.py       |  2 +-
 tests/test_google_model.py | 24 ++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/agent/dashboard/options.py b/agent/dashboard/options.py
index 97d5a40c..0562786b 100644
--- a/agent/dashboard/options.py
+++ b/agent/dashboard/options.py
@@ -25,6 +25,12 @@ SUPPORTED_MODELS: list[ModelOption] = [
         "efforts": ["none", "low", "medium", "high", "xhigh"],
         "default_effort": "xhigh",
     },
+    {
+        "id": "google_genai:gemini-3.5-flash",
+        "label": "Gemini 3.5 Flash",
+        "efforts": ["minimal", "low", "medium", "high"],
+        "default_effort": "medium",
+    },
     {
         "id": "fireworks:accounts/fireworks/models/kimi-k2p6",
         "label": "Kimi K2.6",
@@ -63,6 +69,20 @@ def _provider_of(model_id: str) -> str | None:
     return provider if rest else None
 
 
+def _fallback_effort_for(model: ModelOption, effort: object) -> str | None:
+    if not isinstance(effort, str):
+        return None
+    if effort in model["efforts"]:
+        return effort
+    if (
+        model["id"].startswith("google_genai:")
+        and effort == "none"
+        and "minimal" in model["efforts"]
+    ):
+        return "minimal"
+    return None
+
+
 def provider_fallback_pair(model_id: object, effort: object = None) -> tuple[str, str] | None:
     """Newest supported ``(model_id, effort)`` for the same provider as ``model_id``.
 
@@ -79,8 +99,7 @@ def provider_fallback_pair(model_id: object, effort: object = None) -> tuple[str
         return None
     for m in SUPPORTED_MODELS:
         if _provider_of(m["id"]) == provider:
-            new_effort = effort if (isinstance(effort, str) and effort in m["efforts"]) else None
-            return m["id"], new_effort or m["default_effort"]
+            return m["id"], _fallback_effort_for(m, effort) or m["default_effort"]
     return None
 
 
diff --git a/agent/utils/model.py b/agent/utils/model.py
index f4bf536e..86f5f480 100644
--- a/agent/utils/model.py
+++ b/agent/utils/model.py
@@ -126,7 +126,7 @@ def fireworks_reasoning_effort_for(profile_effort: str | None) -> FireworksReaso
 
 def google_thinking_level_for(profile_effort: str | None) -> GoogleThinkingLevel | None:
     """Map profile effort to Gemini 3+ ``thinking_level``."""
-    if profile_effort == "none":
+    if profile_effort in ("minimal", "none"):
         return "minimal"
     if profile_effort == "low":
         return "low"
diff --git a/tests/test_google_model.py b/tests/test_google_model.py
index c6788795..3b7d0c1f 100644
--- a/tests/test_google_model.py
+++ b/tests/test_google_model.py
@@ -1,3 +1,4 @@
+from agent.dashboard.options import SUPPORTED_MODELS, provider_fallback_pair
 from agent.utils.model import (
     google_thinking_level_for,
     is_gemini_3_family,
@@ -11,11 +12,34 @@ def test_gemini_3_family_detection() -> None:
 
 
 def test_google_thinking_level_maps_effort() -> None:
+    assert google_thinking_level_for("minimal") == "minimal"
+    assert google_thinking_level_for("none") == "minimal"
     assert google_thinking_level_for("medium") == "medium"
     assert google_thinking_level_for("high") == "high"
     assert google_thinking_level_for("unknown") is None
 
 
+def test_gemini_35_flash_is_supported_with_documented_efforts() -> None:
+    gemini = next(m for m in SUPPORTED_MODELS if m["id"] == "google_genai:gemini-3.5-flash")
+    assert gemini["label"] == "Gemini 3.5 Flash"
+    assert gemini["efforts"] == ["minimal", "low", "medium", "high"]
+    assert gemini["default_effort"] == "medium"
+
+
+def test_google_provider_fallback_uses_gemini_35_flash() -> None:
+    assert provider_fallback_pair("google_genai:gemini-3-flash-preview", "high") == (
+        "google_genai:gemini-3.5-flash",
+        "high",
+    )
+
+
+def test_google_provider_fallback_maps_legacy_none_to_minimal() -> None:
+    assert provider_fallback_pair("google_genai:gemini-3-flash-preview", "none") == (
+        "google_genai:gemini-3.5-flash",
+        "minimal",
+    )
+
+
 def test_provider_model_kwargs_for_google() -> None:
     kwargs = provider_model_kwargs(
         "google_genai:gemini-3.5-flash",