fix(ui): filter known params from litellm_extra_params to allow re-editing

Fixes #23998

The LiteLLM Params JSON textarea was showing all params including those
with dedicated form fields (api_base, model, etc.). This caused confusion
when users tried to remove custom params - they would reappear because
the individual form fields would still have those values.

Changes:
- Added KNOWN_LITELLM_PARAMS constant listing all params with dedicated form fields
- Filter out known params from litellm_extra_params initialization
- Updated tests to verify known params don't appear in the textarea
- Added test to verify custom params can be removed successfully

ui/litellm-dashboard/src/components/model_info_view.test.tsx

@@ -526,17 +526,21 @@ describe("ModelInfoView", () => {
 
     await user.click(screen.getByRole("button", { name: /edit settings/i }));
 
+    // Find the LiteLLM Params textarea by placeholder
     const litellmParamsInput = screen
       .getAllByRole("textbox")
       .find(
         (input) =>
           input.tagName === "TEXTAREA" &&
-          (input as HTMLTextAreaElement).value.includes('"custom_llm_provider"'),
+          input.getAttribute("placeholder")?.includes("rpm"),
       );
     expect(litellmParamsInput).toBeDefined();
     if (!litellmParamsInput) {
       return;
     }
+    // Known params like custom_llm_provider should NOT be in the textarea
+    expect((litellmParamsInput as HTMLTextAreaElement).value).not.toContain("custom_llm_provider");
+    // litellm_credential_name should also NOT be in the textarea
     expect((litellmParamsInput as HTMLTextAreaElement).value).not.toContain("litellm_credential_name");
     await user.clear(litellmParamsInput);
     await user.paste(`{"litellm_credential_name":"from-json","timeout":42}`);
@@ -636,4 +640,64 @@ describe("ModelInfoView", () => {
       expect(screen.getByText(/Created By/)).toBeInTheDocument();
     });
   });
+
+  it("should allow removing custom params from LiteLLM Params json", async () => {
+    const user = userEvent.setup();
+    const modelWithCustomParams = {
+      ...defaultModelData,
+      litellm_params: {
+        ...defaultModelData.litellm_params,
+        litellm_image_enabled: true,
+        custom_param: "value",
+      },
+    };
+
+    mockUseModelsInfo.mockReturnValue({
+      data: {
+        data: [modelWithCustomParams],
+      },
+      isLoading: false,
+      error: null,
+    });
+
+    render(<ModelInfoView {...DEFAULT_ADMIN_PROPS} />, { wrapper });
+
+    await waitFor(() => {
+      expect(screen.getByRole("button", { name: /edit settings/i })).toBeInTheDocument();
+    });
+
+    await user.click(screen.getByRole("button", { name: /edit settings/i }));
+
+    // Find the LiteLLM Params textarea
+    const litellmParamsInput = screen
+      .getAllByRole("textbox")
+      .find(
+        (input) =>
+          input.tagName === "TEXTAREA" &&
+          input.getAttribute("placeholder")?.includes("rpm"),
+      );
+    expect(litellmParamsInput).toBeDefined();
+    if (!litellmParamsInput) {
+      return;
+    }
+
+    // Verify custom params are in the textarea
+    expect((litellmParamsInput as HTMLTextAreaElement).value).toContain("litellm_image_enabled");
+    expect((litellmParamsInput as HTMLTextAreaElement).value).toContain("custom_param");
+
+    // Remove the custom params
+    await user.clear(litellmParamsInput);
+    await user.paste(`{}`);
+
+    await user.click(screen.getByRole("button", { name: /save changes/i }));
+
+    await waitFor(() => {
+      expect(mockModelPatchUpdateCall).toHaveBeenCalled();
+    });
+
+    // Verify the payload does not include the removed custom params
+    const updatePayload = mockModelPatchUpdateCall.mock.calls[0][1];
+    expect(updatePayload.litellm_params.litellm_image_enabled).toBeUndefined();
+    expect(updatePayload.litellm_params.custom_param).toBeUndefined();
+  });
 });

ui/litellm-dashboard/src/components/model_info_view.tsx

@@ -44,6 +44,26 @@ import NumericalInput from "./shared/numerical_input";
 import { Tag } from "./tag_management/types";
 import { getDisplayModelName } from "./view_model/model_name_display";
 
+// Known LiteLLM params that have dedicated form fields - these should not appear in litellm_extra_params
+const KNOWN_LITELLM_PARAMS = [
+  "model",
+  "api_base",
+  "custom_llm_provider",
+  "organization",
+  "tpm",
+  "rpm",
+  "max_retries",
+  "timeout",
+  "stream_timeout",
+  "input_cost_per_token",
+  "output_cost_per_token",
+  "tags",
+  "guardrails",
+  "vector_store_ids",
+  "cache_control_injection_points",
+  "litellm_credential_name",
+];
+
 interface ModelInfoViewProps {
   modelId: string;
   onClose: () => void;
@@ -640,7 +660,7 @@ export default function ModelInfoView({
                     litellm_extra_params: JSON.stringify(
                       Object.fromEntries(
                         Object.entries(localModelData.litellm_params || {}).filter(
-                          ([key]) => key !== "litellm_credential_name",
+                          ([key]) => !KNOWN_LITELLM_PARAMS.includes(key),
                         ),
                       ),
                       null,