diff --git a/apps/desktop/src/settings/ai/shared/index.tsx b/apps/desktop/src/settings/ai/shared/index.tsx
index 09dfac14439..0e105db9cd1 100644
--- a/apps/desktop/src/settings/ai/shared/index.tsx
+++ b/apps/desktop/src/settings/ai/shared/index.tsx
@@ -255,7 +255,7 @@ export function useProviderAvailability(
           return provider.checkAvailability(baseUrl, apiKey);
         try {
           await verifyProviderCredentials(
-            { provider: provider.id, baseUrl, apiKey },
+            { type: providerType, provider: provider.id, baseUrl, apiKey },
             providerFetch,
             signal,
           );
diff --git a/apps/desktop/src/settings/ai/shared/provider-availability.test.tsx b/apps/desktop/src/settings/ai/shared/provider-availability.test.tsx
index 1c99411eca3..b23653e3796 100644
--- a/apps/desktop/src/settings/ai/shared/provider-availability.test.tsx
+++ b/apps/desktop/src/settings/ai/shared/provider-availability.test.tsx
@@ -3,7 +3,12 @@ import { act, cleanup, renderHook, waitFor } from "@testing-library/react";
 import type { ReactNode } from "react";
 import { afterEach, beforeEach, expect, test, vi } from "vitest";
 
-const mocks = vi.hoisted(() => ({ fetch: vi.fn(), key: 0, baseUrl: "" }));
+const mocks = vi.hoisted(() => ({
+  fetch: vi.fn(),
+  key: 0,
+  baseUrl: "",
+  provider: "openai",
+}));
 
 vi.mock("@tauri-apps/plugin-http", () => ({ fetch: mocks.fetch }));
 vi.mock("~/auth/billing-context", () => ({
@@ -11,7 +16,7 @@ vi.mock("~/auth/billing-context", () => ({
 }));
 vi.mock("~/settings/providers", () => ({
   useAiProviders: (type: string) => ({
-    [`${type}:openai`]: {
+    [`${type}:${mocks.provider}`]: {
       api_key: `saved-key-${mocks.key}`,
       base_url: mocks.baseUrl,
     },
@@ -24,6 +29,7 @@ beforeEach(() => {
   mocks.fetch.mockReset();
   mocks.key++;
   mocks.baseUrl = "";
+  mocks.provider = "openai";
 });
 afterEach(cleanup);
 
@@ -60,6 +66,28 @@ test.each([
   },
 );
 
+test("keeps a saved Custom STT endpoint available without model-list verification", async () => {
+  mocks.provider = "custom";
+  mocks.baseUrl = "http://127.0.0.1:8000/v1";
+  mocks.fetch.mockResolvedValue(new Response(null, { status: 404 }));
+  const { result, client, unmount } = setup("stt");
+  await waitFor(() => expect(result.current.custom).toBe(true));
+  expect(mocks.fetch).not.toHaveBeenCalled();
+  unmount();
+  client.clear();
+});
+
+test("still probes Custom LLM credentials and rejects an unsupported model-list endpoint", async () => {
+  mocks.provider = "custom";
+  mocks.baseUrl = "http://127.0.0.1:8000/v1";
+  mocks.fetch.mockResolvedValue(new Response(null, { status: 401 }));
+  const { result, client, unmount } = setup("llm");
+  await waitFor(() => expect(result.current.custom).toBe(false));
+  expect(mocks.fetch).toHaveBeenCalled();
+  unmount();
+  client.clear();
+});
+
 function setup(type: "stt" | "llm") {
   const client = new QueryClient({
     defaultOptions: { queries: { retry: false } },
@@ -68,7 +96,7 @@ function setup(type: "stt" | "llm") {
     () =>
       useProviderAvailability(type, [
         {
-          id: "openai",
+          id: mocks.provider,
           displayName: "OpenAI",
           icon: null,
           baseUrl: "https://api.openai.com/v1",
diff --git a/apps/desktop/src/settings/providers.test.ts b/apps/desktop/src/settings/providers.test.ts
index a67908a4115..c4e790bac47 100644
--- a/apps/desktop/src/settings/providers.test.ts
+++ b/apps/desktop/src/settings/providers.test.ts
@@ -122,6 +122,35 @@ describe("SQLite AI providers", () => {
     queryClient.clear();
   });
 
+  it("saves Custom STT without requiring a model-list endpoint", async () => {
+    const { verifyProviderCredentials } = await vi.importActual<
+      typeof import("@anlg/provider-validation")
+    >("@anlg/provider-validation");
+    mocks.verify.mockImplementation(verifyProviderCredentials);
+    mocks.execute.mockResolvedValue([]);
+    mocks.fetch.mockResolvedValue(new Response(null, { status: 404 }));
+    const queryClient = new QueryClient();
+    const wrapper = ({ children }: { children: ReactNode }) =>
+      createElement(QueryClientProvider, { client: queryClient }, children);
+    const { result, unmount } = renderHook(
+      () => useSetAiProvider("stt", "custom", { verifyCredentials: true }),
+      { wrapper },
+    );
+    await result.current.mutateAsync({
+      base_url: "http://127.0.0.1:8000/v1",
+      api_key: "local-key",
+    });
+    expect(mocks.fetch).not.toHaveBeenCalled();
+    expect(mocks.setSecret).toHaveBeenCalledWith(
+      "ai-provider-api-keys",
+      "stt:custom",
+      "local-key",
+    );
+    expect(mocks.executeTransaction).toHaveBeenCalledOnce();
+    unmount();
+    queryClient.clear();
+  });
+
   it("saves a valid local provider and rejects an invalid replacement when the server restricts origins", async () => {
     const { verifyProviderCredentials } = await vi.importActual<
       typeof import("@anlg/provider-validation")
@@ -201,7 +230,12 @@ describe("SQLite AI providers", () => {
       );
       await result.current.mutateAsync({ api_key: "working", base_url: draft });
       expect(mocks.verify).toHaveBeenCalledWith(
-        { provider: "openai", baseUrl: expected, apiKey: "working" },
+        {
+          type: "llm",
+          provider: "openai",
+          baseUrl: expected,
+          apiKey: "working",
+        },
         expect.any(Function),
       );
       const persisted = mocks.executeTransaction.mock.calls[0][0][0].params[0];
diff --git a/apps/desktop/src/settings/providers.ts b/apps/desktop/src/settings/providers.ts
index 3300519ee46..d6a519828ef 100644
--- a/apps/desktop/src/settings/providers.ts
+++ b/apps/desktop/src/settings/providers.ts
@@ -223,6 +223,7 @@ export function useSetAiProvider(
           defaultBaseUrl.trim();
         await verifyProviderCredentials(
           {
+            type,
             provider: providerId,
             baseUrl,
             apiKey,
diff --git a/packages/provider-validation/src/index.test.mjs b/packages/provider-validation/src/index.test.mjs
index b568705a379..ca219894827 100644
--- a/packages/provider-validation/src/index.test.mjs
+++ b/packages/provider-validation/src/index.test.mjs
@@ -78,6 +78,56 @@ test("a public model catalog cannot validate a key", async () => {
   );
 });
 
+test("custom STT validates configuration without probing an OpenAI model catalog", async () => {
+  const fetcher = async () => {
+    assert.fail("Custom STT must not send model-list or control-key requests");
+  };
+  for (const baseUrl of [
+    "http://127.0.0.1:8000/v1",
+    "https://stt.example/v1",
+  ]) {
+    await verifyProviderCredentials(
+      { ...credential, type: "stt", provider: "custom", baseUrl },
+      fetcher,
+    );
+  }
+});
+
+test("custom STT still rejects unsafe URLs and malformed keys before saving", async () => {
+  for (const update of [
+    { baseUrl: "not-a-url" },
+    { baseUrl: "http://stt.example/v1" },
+    { baseUrl: "https://user:password@stt.example/v1" },
+    { baseUrl: "https://stt.example/v1?key=secret" },
+    { apiKey: "" },
+    { apiKey: "bad\nkey" },
+  ]) {
+    await assert.rejects(
+      verifyProviderCredentials(
+        { ...credential, type: "stt", provider: "custom", ...update },
+        async () => assert.fail("Invalid configuration must not send requests"),
+      ),
+      ProviderCredentialError,
+    );
+  }
+});
+
+test("Custom LLM still requires key proof after accepting the same STT configuration", async () => {
+  const custom = { ...credential, provider: "custom" };
+  let calls = 0;
+  const fetcher = async () => {
+    calls++;
+    return Response.json({ data: [] });
+  };
+  await verifyProviderCredentials({ ...custom, type: "stt" }, fetcher);
+  assert.equal(calls, 0);
+  await assert.rejects(
+    verifyProviderCredentials({ ...custom, type: "llm" }, fetcher),
+    /doesn’t support API key verification/,
+  );
+  assert.equal(calls, 2);
+});
+
 test("a gateway must accept the candidate key and reject the control key", async () => {
   const keys = [];
   await verifyProviderCredentials(
diff --git a/packages/provider-validation/src/index.ts b/packages/provider-validation/src/index.ts
index 58d33bba4b4..9ca1379c033 100644
--- a/packages/provider-validation/src/index.ts
+++ b/packages/provider-validation/src/index.ts
@@ -1,6 +1,7 @@
 import { sha256 } from "js-sha256";
 
 export type ProviderCredential = {
+  type?: "stt" | "llm";
   provider: string;
   baseUrl: string;
   apiKey: string;
@@ -50,6 +51,10 @@ export async function verifyProviderCredentials(
     throw new ProviderCredentialError("Use HTTPS for provider credentials.");
 
   signal?.throwIfAborted();
+  // Deepgram-compatible listen servers need not expose a model catalog or a
+  // credential-probe endpoint. Their credentials are checked when transcribing.
+  if (credential.type === "stt" && credential.provider === "custom") return;
+
   const identity = providerCredentialIdentity({ ...credential, apiKey });
   const recent = verified.get(fetcher) ?? new Map<string, number>();
   verified.set(fetcher, recent);