diff --git a/src/shared/model-capability-heuristics.ts b/src/shared/model-capability-heuristics.ts
index 61d9e5cbc..ec0dbf5ac 100644
--- a/src/shared/model-capability-heuristics.ts
+++ b/src/shared/model-capability-heuristics.ts
@@ -45,6 +45,12 @@ export const HEURISTIC_MODEL_FAMILY_REGISTRY: ReadonlyArray<HeuristicModelFamily
     includes: ["gemini"],
     variants: ["low", "medium", "high"],
   },
+  {
+    family: "grok",
+    includes: ["grok"],
+    variants: ["low", "medium", "high"],
+    reasoningEfforts: ["low", "medium", "high"],
+  },
   {
     family: "kimi-thinking",
     includes: ["kimi-thinking", "k2-thinking", "k2-think"],
diff --git a/src/shared/model-settings-compatibility.test.ts b/src/shared/model-settings-compatibility.test.ts
index fd3568755..4936cf0e4 100644
--- a/src/shared/model-settings-compatibility.test.ts
+++ b/src/shared/model-settings-compatibility.test.ts
@@ -253,6 +253,7 @@ describe("resolveCompatibleModelSettings", () => {
       hasReasoningEffort: boolean
     }> = [
       { name: "Gemini", modelID: "gemini-3.1-pro", expectedVariants: ["low", "medium", "high"], hasReasoningEffort: false },
+      { name: "Grok", modelID: "grok-4.3", expectedVariants: ["low", "medium", "high"], hasReasoningEffort: true },
       { name: "Kimi (kimi)", modelID: "kimi-k2.5", expectedVariants: ["low", "medium", "high"], hasReasoningEffort: false },
       { name: "Kimi (k2)", modelID: "k2-v2", expectedVariants: ["low", "medium", "high"], hasReasoningEffort: false },
       { name: "GLM", modelID: "glm-5", expectedVariants: ["low", "medium", "high"], hasReasoningEffort: false },