diff --git a/docs/providers/xai.md b/docs/providers/xai.md
index cafbfd9df729..836285a2e132 100644
--- a/docs/providers/xai.md
+++ b/docs/providers/xai.md
@@ -504,9 +504,10 @@ Legacy aliases still normalize to the canonical bundled ids:
       sign-in URL. xAI decides which accounts can receive OAuth API tokens, and
       the consent page may show Grok Build even though OpenClaw does not require
       the Grok Build app.
-    - `grok-4.20-multi-agent-experimental-beta-0304` is not supported on the
-      normal xAI provider path because it requires a different upstream API
-      surface than the standard OpenClaw xAI transport.
+    - OpenClaw does not currently expose the xAI multi-agent model family. xAI
+      serves these models through the Responses API, but they do not accept the
+      client-side or custom tools used by OpenClaw's shared agent loop. See the
+      [xAI multi-agent limitations](https://docs.x.ai/developers/model-capabilities/text/multi-agent#limitations).
     - xAI Realtime voice is not registered as an OpenClaw provider yet. It
       needs a different bidirectional voice session contract than batch STT or
       streaming transcription.
diff --git a/extensions/xai/index.ts b/extensions/xai/index.ts
index 0a13fb30d4d4..a8ea0d68bc91 100644
--- a/extensions/xai/index.ts
+++ b/extensions/xai/index.ts
@@ -262,12 +262,6 @@ export default defineSingleProviderPluginEntry({
     resolveThinkingProfile,
     isModernModelRef: ({ modelId }) => isModernXaiModel(modelId),
     classifyFailoverReason: ({ errorMessage }) => classifyXaiFailoverReason(errorMessage),
-    buildUnknownModelHint: ({ modelId }) => {
-      if (modelId.toLowerCase().includes("multi-agent")) {
-        return "xAI multi-agent models are not supported on the standard xAI API-key provider path. See https://docs.openclaw.ai/providers/xai for supported models.";
-      }
-      return undefined;
-    },
   },
   register(api) {
     api.registerWebSearchProvider(createXaiWebSearchProvider());
diff --git a/extensions/xai/openclaw.plugin.json b/extensions/xai/openclaw.plugin.json
index bd4141880618..9f28d1f10109 100644
--- a/extensions/xai/openclaw.plugin.json
+++ b/extensions/xai/openclaw.plugin.json
@@ -31,6 +31,45 @@
       }
     }
   },
+  "modelCatalog": {
+    "suppressions": [
+      {
+        "provider": "xai",
+        "model": "grok-4.20-multi-agent-0309",
+        "reason": "OpenClaw does not currently support xAI multi-agent models; choose another xAI model. See https://docs.openclaw.ai/providers/xai."
+      },
+      {
+        "provider": "xai",
+        "model": "grok-4.20-multi-agent",
+        "reason": "OpenClaw does not currently support xAI multi-agent models; choose another xAI model. See https://docs.openclaw.ai/providers/xai."
+      },
+      {
+        "provider": "xai",
+        "model": "grok-4.20-multi-agent-latest",
+        "reason": "OpenClaw does not currently support xAI multi-agent models; choose another xAI model. See https://docs.openclaw.ai/providers/xai."
+      },
+      {
+        "provider": "xai",
+        "model": "grok-4.20-multi-agent-beta-latest",
+        "reason": "OpenClaw does not currently support xAI multi-agent models; choose another xAI model. See https://docs.openclaw.ai/providers/xai."
+      },
+      {
+        "provider": "xai",
+        "model": "grok-4.20-multi-agent-experimental-beta-0304",
+        "reason": "OpenClaw does not currently support xAI multi-agent models; choose another xAI model. See https://docs.openclaw.ai/providers/xai."
+      },
+      {
+        "provider": "xai",
+        "model": "grok-4.20-multi-agent-experimental-beta-latest",
+        "reason": "OpenClaw does not currently support xAI multi-agent models; choose another xAI model. See https://docs.openclaw.ai/providers/xai."
+      },
+      {
+        "provider": "xai",
+        "model": "grok-4.20-multi-agent-beta-0309",
+        "reason": "OpenClaw does not currently support xAI multi-agent models; choose another xAI model. See https://docs.openclaw.ai/providers/xai."
+      }
+    ]
+  },
   "syntheticAuthRefs": ["xai"],
   "setup": {
     "providers": [
diff --git a/extensions/xai/openclaw.plugin.test.ts b/extensions/xai/openclaw.plugin.test.ts
new file mode 100644
index 000000000000..05aa914bd398
--- /dev/null
+++ b/extensions/xai/openclaw.plugin.test.ts
@@ -0,0 +1,34 @@
+import { readFileSync } from "node:fs";
+import { describe, expect, it } from "vitest";
+
+const manifest = JSON.parse(
+  readFileSync(new URL("./openclaw.plugin.json", import.meta.url), "utf8"),
+) as {
+  modelCatalog?: {
+    suppressions?: Array<{ provider?: string; model?: string }>;
+  };
+};
+
+const XAI_MULTI_AGENT_MODELS = [
+  "grok-4.20-multi-agent-0309",
+  "grok-4.20-multi-agent",
+  "grok-4.20-multi-agent-latest",
+  "grok-4.20-multi-agent-beta-latest",
+  "grok-4.20-multi-agent-experimental-beta-0304",
+  "grok-4.20-multi-agent-experimental-beta-latest",
+  "grok-4.20-multi-agent-beta-0309",
+] as const;
+
+describe("xAI plugin manifest", () => {
+  it("suppresses the unsupported multi-agent model aliases", () => {
+    const suppressionRefs = new Set(
+      (manifest.modelCatalog?.suppressions ?? []).map(
+        (suppression) => `${suppression.provider}/${suppression.model}`,
+      ),
+    );
+
+    for (const model of XAI_MULTI_AGENT_MODELS) {
+      expect(suppressionRefs).toContain(`xai/${model}`);
+    }
+  });
+});
diff --git a/src/agents/embedded-agent-runner/model.test.ts b/src/agents/embedded-agent-runner/model.test.ts
index 319c4ebe81fd..9ddbb21e3f01 100644
--- a/src/agents/embedded-agent-runner/model.test.ts
+++ b/src/agents/embedded-agent-runner/model.test.ts
@@ -61,6 +61,10 @@ vi.mock("../model-suppression.js", () => {
     return undefined;
   }
 
+  function isUnsupportedXaiMultiAgentModel(provider?: string, id?: string): boolean {
+    return provider === "xai" && id?.trim().toLowerCase() === "grok-4.20-multi-agent-0309";
+  }
+
   return {
     shouldSuppressBuiltInModel: ({
       provider,
@@ -79,6 +83,9 @@ vi.mock("../model-suppression.js", () => {
       ) {
         return true;
       }
+      if (isUnsupportedXaiMultiAgentModel(provider, id)) {
+        return true;
+      }
       return (
         (provider === "qwen" || provider === "modelstudio") &&
         id?.trim().toLowerCase() === "qwen3.6-plus" &&
@@ -92,7 +99,7 @@ vi.mock("../model-suppression.js", () => {
       ) {
         return true;
       }
-      return false;
+      return isUnsupportedXaiMultiAgentModel(provider, id);
     },
     buildSuppressedBuiltInModelError: ({
       provider,
@@ -116,6 +123,9 @@ vi.mock("../model-suppression.js", () => {
       ) {
         return `Unknown model: ${provider}/gpt-5.3-codex-spark. gpt-5.3-codex-spark is available only through ChatGPT/Codex OAuth. Run \`openclaw models auth login --provider openai\` and use openai/gpt-5.3-codex-spark with that OAuth profile; OpenAI API-key auth cannot use this model.`;
       }
+      if (isUnsupportedXaiMultiAgentModel(provider, id)) {
+        return "Unknown model: xai/grok-4.20-multi-agent-0309. OpenClaw does not currently support xAI multi-agent models; choose another xAI model. See https://docs.openclaw.ai/providers/xai.";
+      }
       return undefined;
     },
   };
@@ -3451,6 +3461,27 @@ describe("resolveModel", () => {
     );
   });
 
+  it("does not build a configured fallback for unsupported xAI multi-agent models", () => {
+    const cfg = {
+      models: {
+        providers: {
+          xai: {
+            baseUrl: "https://api.x.ai/v1",
+            api: "openai-completions",
+            models: [],
+          },
+        },
+      },
+    } as unknown as OpenClawConfig;
+
+    const result = resolveModelForTest("xai", "grok-4.20-multi-agent-0309", "/tmp/agent", cfg);
+
+    expect(result.model).toBeUndefined();
+    expect(result.error).toBe(
+      "Unknown model: xai/grok-4.20-multi-agent-0309. OpenClaw does not currently support xAI multi-agent models; choose another xAI model. See https://docs.openclaw.ai/providers/xai.",
+    );
+  });
+
   it("rejects stale openai gpt-5.3-codex-spark discovery rows", () => {
     mockDiscoveredModel(discoverModels, {
       provider: "openai",
diff --git a/src/agents/embedded-agent-runner/model.ts b/src/agents/embedded-agent-runner/model.ts
index 5e6ec9b23e2f..9af7a6d61b77 100644
--- a/src/agents/embedded-agent-runner/model.ts
+++ b/src/agents/embedded-agent-runner/model.ts
@@ -522,7 +522,6 @@ function mergeStaticCatalogInlineModel(
 }
 
 function hasConfiguredFallbackSurface(params: {
-  provider?: string;
   providerConfig: InlineProviderConfig | undefined;
   configuredModel: ReturnType<typeof findConfiguredProviderModel>;
   modelId: string;
@@ -533,18 +532,6 @@ function hasConfiguredFallbackSurface(params: {
   if (params.configuredModel) {
     return true;
   }
-  // xAI's catalog explicitly excludes multi-agent model ids (they require a
-  // different upstream API surface than the standard API-key provider path).
-  // If the provider rejected this model via its dynamic resolution, do not
-  // synthesize a configured-provider fallback that will silently 400.
-  // See: https://docs.openclaw.ai/providers/xai
-  if (
-    params.provider &&
-    normalizeProviderId(params.provider) === "xai" &&
-    params.modelId.toLowerCase().includes("multi-agent")
-  ) {
-    return false;
-  }
   const baseUrl = params.providerConfig?.baseUrl?.trim();
   return Boolean(baseUrl);
 }
@@ -1258,7 +1245,7 @@ function resolveConfiguredFallbackModel(params: {
   const providerConfig = resolveConfiguredProviderConfig(cfg, provider);
   const requestTimeoutMs = resolveProviderRequestTimeoutMs(providerConfig?.timeoutSeconds);
   const configuredModel = findConfiguredProviderModel(providerConfig, provider, modelId);
-  if (!hasConfiguredFallbackSurface({ provider, providerConfig, configuredModel, modelId })) {
+  if (!hasConfiguredFallbackSurface({ providerConfig, configuredModel, modelId })) {
     return undefined;
   }
   const staticCatalogModel = resolveBundledStaticCatalogModel({