fix: update google provider to handle gemma 4 thinking levels and route between MINIMAL and HIGH (#2903)

resolves #2812

Co-authored-by: Mario Zechner <badlogicgames@gmail.com>

packages/ai/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed thinking levels for Gemma 4 models to use `thinkingLevel` and map Pi reasoning levels to the model's supported thinking levels ([#2903](https://github.com/badlogic/pi-mono/pull/2903) by [@aadishv](https://github.com/aadishv))
+
 ## [0.66.1] - 2026-04-08
 
 ## [0.66.0] - 2026-04-08

packages/ai/src/providers/google.ts

@@ -293,12 +293,12 @@ export const streamSimpleGoogle: StreamFunction<"google-generative-ai", SimpleSt
 	const effort = clampReasoning(options.reasoning)!;
 	const googleModel = model as Model<"google-generative-ai">;
 
-	if (isGemini3ProModel(googleModel) || isGemini3FlashModel(googleModel)) {
+	if (isGemini3ProModel(googleModel) || isGemini3FlashModel(googleModel) || isGemma4Model(googleModel)) {
 		return streamGoogle(model, context, {
 			...base,
 			thinking: {
 				enabled: true,
-				level: getGemini3ThinkingLevel(effort, googleModel),
+				level: getThinkingLevel(effort, googleModel),
 			},
 		} satisfies GoogleOptions);
 	}
@@ -394,6 +394,10 @@ function buildParams(
 
 type ClampedThinkingLevel = Exclude<ThinkingLevel, "xhigh">;
 
+function isGemma4Model(model: Model<"google-generative-ai">): boolean {
+	return /gemma-?4/.test(model.id.toLowerCase());
+}
+
 function isGemini3ProModel(model: Model<"google-generative-ai">): boolean {
 	return /gemini-3(?:\.\d+)?-pro/.test(model.id.toLowerCase());
 }
@@ -412,15 +416,15 @@ function getDisabledThinkingConfig(model: Model<"google-generative-ai">): Thinki
 	if (isGemini3FlashModel(model)) {
 		return { thinkingLevel: "MINIMAL" as any };
 	}
+	if (isGemma4Model(model)) {
+		return { thinkingLevel: "MINIMAL" as any };
+	}
 
 	// Gemini 2.x supports disabling via thinkingBudget = 0.
 	return { thinkingBudget: 0 };
 }
 
-function getGemini3ThinkingLevel(
-	effort: ClampedThinkingLevel,
-	model: Model<"google-generative-ai">,
-): GoogleThinkingLevel {
+function getThinkingLevel(effort: ClampedThinkingLevel, model: Model<"google-generative-ai">): GoogleThinkingLevel {
 	if (isGemini3ProModel(model)) {
 		switch (effort) {
 			case "minimal":
@@ -431,6 +435,16 @@ function getGemini3ThinkingLevel(
 				return "HIGH";
 		}
 	}
+	if (isGemma4Model(model)) {
+		switch (effort) {
+			case "minimal":
+			case "low":
+				return "MINIMAL";
+			case "medium":
+			case "high":
+				return "HIGH";
+		}
+	}
 	switch (effort) {
 		case "minimal":
 			return "MINIMAL";

packages/coding-agent/docs/models.md

@@ -90,6 +90,33 @@ Override defaults when you need specific values:
 
 The file reloads each time you open `/model`. Edit during session; no restart needed.
 
+## Google AI Studio Example
+
+Use `google-generative-ai` with a `baseUrl` to add models from Google AI Studio, including custom Gemma 4 entries:
+
+```json
+{
+  "providers": {
+    "my-google": {
+      "baseUrl": "https://generativelanguage.googleapis.com/v1beta",
+      "api": "google-generative-ai",
+      "apiKey": "GEMINI_API_KEY",
+      "models": [
+        {
+          "id": "gemma-4-31b-it",
+          "name": "Gemma 4 31B",
+          "input": ["text", "image"],
+          "contextWindow": 262144,
+          "reasoning": true
+        }
+      ]
+    }
+  }
+}
+```
+
+The `baseUrl` is required when adding custom models to the `google-generative-ai` API type.
+
 ## Supported APIs
 
 | API | Description |