fix: omit default temperature for custom models (#3301)

AGENTS.md

@@ -37,6 +37,10 @@ npm run init-precommit
 
 **Note:** Running `npm install` may update `package-lock.json` with version changes or peer dependency flag removals. If rebasing or performing git operations, commit these changes first to avoid "unstaged changes" errors.
 
+## Git worktrees
+
+When you create a new git worktree for this repository, run `npm install` inside the new worktree before starting development. Each worktree has its own working directory and needs its dependencies installed there.
+
 ## Pre-commit checks
 
 RUN THE FOLLOWING CHECKS before you do a commit.

src/__tests__/token_utils.test.ts

+import { describe, expect, it, vi } from "vitest";
+
+import { getTemperature } from "../ipc/utils/token_utils";
+import { findLanguageModel } from "../ipc/utils/findLanguageModel";
+
+vi.mock("../../src/main/settings", () => ({
+  readSettings: vi.fn(),
+}));
+
+vi.mock("../ipc/utils/findLanguageModel", () => ({
+  findLanguageModel: vi.fn(),
+}));
+
+const mockFindLanguageModel = vi.mocked(findLanguageModel);
+
+describe("getTemperature", () => {
+  it("does not set a default temperature for custom models", async () => {
+    mockFindLanguageModel.mockResolvedValueOnce({
+      id: 1,
+      apiName: "custom-model",
+      displayName: "Custom Model",
+      type: "custom",
+    });
+
+    await expect(
+      getTemperature({ provider: "custom::provider", name: "custom-model" }),
+    ).resolves.toBeUndefined();
+  });
+
+  it("keeps the fallback temperature for non-custom models without metadata", async () => {
+    mockFindLanguageModel.mockResolvedValueOnce({
+      apiName: "cloud-model",
+      displayName: "Cloud Model",
+      type: "cloud",
+    });
+
+    await expect(
+      getTemperature({ provider: "provider", name: "cloud-model" }),
+    ).resolves.toBe(0);
+  });
+});

src/ipc/utils/token_utils.ts

@@ -33,8 +33,11 @@ export async function getMaxTokens(
 
 export async function getTemperature(
   model: LargeLanguageModel,
-): Promise<number> {
+): Promise<number | undefined> {
   const modelOption = await findLanguageModel(model);
+  if (modelOption?.type === "custom") {
+    return modelOption.temperature;
+  }
   return modelOption?.temperature ?? 0;
 }