diff --git a/src/media-understanding/providers/index.test.ts b/src/media-understanding/providers/index.test.ts
index 31bc041a608..d40e4ac6082 100644
--- a/src/media-understanding/providers/index.test.ts
+++ b/src/media-understanding/providers/index.test.ts
@@ -60,4 +60,28 @@ describe("media-understanding provider registry", () => {
 
     expect(provider?.id).toBe("google");
   });
+
+  it("auto-registers media-understanding for config providers with image-capable models (#51392)", () => {
+    const cfg = {
+      models: {
+        providers: {
+          glm: {
+            models: [{ id: "glm-4.6v", input: ["text", "image"] }],
+          },
+          textOnly: {
+            models: [{ id: "text-model", input: ["text"] }],
+          },
+        },
+      },
+    } as never;
+    const registry = buildMediaUnderstandingRegistry(undefined, cfg);
+    const glmProvider = getMediaUnderstandingProvider("glm", registry);
+    const textOnlyProvider = getMediaUnderstandingProvider("textOnly", registry);
+
+    expect(glmProvider?.id).toBe("glm");
+    expect(glmProvider?.capabilities).toEqual(["image"]);
+    expect(glmProvider?.describeImage).toBeDefined();
+    expect(glmProvider?.describeImages).toBeDefined();
+    expect(textOnlyProvider).toBeUndefined();
+  });
 });
diff --git a/src/media-understanding/providers/index.ts b/src/media-understanding/providers/index.ts
index 521d55caee1..09bf033d5dc 100644
--- a/src/media-understanding/providers/index.ts
+++ b/src/media-understanding/providers/index.ts
@@ -5,6 +5,10 @@ import { getActivePluginRegistry } from "../../plugins/runtime.js";
 import type { MediaUnderstandingProvider } from "../types.js";
 import { deepgramProvider } from "./deepgram/index.js";
 import { groqProvider } from "./groq/index.js";
+import {
+  describeImageWithModel,
+  describeImagesWithModel,
+} from "./image.js";
 
 const PROVIDERS: MediaUnderstandingProvider[] = [groqProvider, deepgramProvider];
 
@@ -48,6 +52,28 @@ export function buildMediaUnderstandingRegistry(
   for (const entry of pluginRegistry?.mediaUnderstandingProviders ?? []) {
     mergeProviderIntoRegistry(registry, entry.provider);
   }
+  // Auto-register media-understanding for config providers with image-capable models (#51392)
+  const configProviders = cfg?.models?.providers;
+  if (configProviders && typeof configProviders === "object") {
+    for (const [providerKey, providerCfg] of Object.entries(configProviders)) {
+      if (!providerKey?.trim()) continue;
+      const normalizedKey = normalizeMediaProviderId(providerKey);
+      if (registry.has(normalizedKey)) continue;
+      const models = (providerCfg as { models?: Array<{ input?: string[] }> })?.models ?? [];
+      const hasImageModel = models.some(
+        (m) => Array.isArray(m?.input) && m.input.includes("image"),
+      );
+      if (hasImageModel) {
+        const autoProvider: MediaUnderstandingProvider = {
+          id: normalizedKey,
+          capabilities: ["image"],
+          describeImage: describeImageWithModel,
+          describeImages: describeImagesWithModel,
+        };
+        mergeProviderIntoRegistry(registry, autoProvider);
+      }
+    }
+  }
   if (overrides) {
     for (const [key, provider] of Object.entries(overrides)) {
       const normalizedKey = normalizeMediaProviderId(key);