diff --git a/src/agents/model-ref-profile.test.ts b/src/agents/model-ref-profile.test.ts
index a8fb98b4bffe..b331ce938aec 100644
--- a/src/agents/model-ref-profile.test.ts
+++ b/src/agents/model-ref-profile.test.ts
@@ -80,6 +80,22 @@ describe("splitTrailingAuthProfile", () => {
     });
   });
 
+  it("keeps @iq* importance-quantization suffixes in model ids", () => {
+    expect(splitTrailingAuthProfile("lmstudio/qwen3.6-27b@iq3_xxs")).toEqual({
+      model: "lmstudio/qwen3.6-27b@iq3_xxs",
+    });
+    expect(splitTrailingAuthProfile("lmstudio/qwen3.6-27b@iq4_xs")).toEqual({
+      model: "lmstudio/qwen3.6-27b@iq4_xs",
+    });
+  });
+
+  it("supports auth profiles after @iq* quant suffixes", () => {
+    expect(splitTrailingAuthProfile("lmstudio/qwen3.6-27b@iq3_xxs@work")).toEqual({
+      model: "lmstudio/qwen3.6-27b@iq3_xxs",
+      profile: "work",
+    });
+  });
+
   it("keeps @4bit/@8bit quant suffixes in model ids", () => {
     expect(splitTrailingAuthProfile("lmstudio-mb-pro/gemma-4-31b@4bit")).toEqual({
       model: "lmstudio-mb-pro/gemma-4-31b@4bit",
diff --git a/src/agents/model-ref-profile.ts b/src/agents/model-ref-profile.ts
index 2469bf228afb..3114ed74e57e 100644
--- a/src/agents/model-ref-profile.ts
+++ b/src/agents/model-ref-profile.ts
@@ -29,9 +29,12 @@ export function splitTrailingAuthProfile(raw: string): {
   // of the model id. These often use '@' (ex: gemma-4-31b-it@q8_0) which would
   // otherwise be misinterpreted as an auth profile delimiter.
   //
+  // Covers standard GGUF quant tags (q4_0, q8_0, q4_k_xl, …) and importance-
+  // quantization variants (iq3_xxs, iq4_xs, …) used by llama.cpp / LM Studio.
+  //
   // If an auth profile is needed, it can still be specified as a second suffix:
-  //   lmstudio/foo@q8_0@work
-  if (/^(?:q\d+(?:_[a-z0-9]+)*|\d+bit)(?:@|$)/i.test(suffixAfterDelimiter())) {
+  //   lmstudio/foo@q8_0@work   lmstudio/foo@iq3_xxs@work
+  if (/^(?:i?q\d+(?:_[a-z0-9]+)*|\d+bit)(?:@|$)/i.test(suffixAfterDelimiter())) {
     const nextDelimiter = trimmed.indexOf("@", profileDelimiter + 1);
     if (nextDelimiter < 0) {
       return { model: trimmed };
diff --git a/src/agents/model-selection.test.ts b/src/agents/model-selection.test.ts
index b7de04c4f7be..134f18f8b710 100644
--- a/src/agents/model-selection.test.ts
+++ b/src/agents/model-selection.test.ts
@@ -894,6 +894,28 @@ describe("model-selection", () => {
       });
     });
 
+    it("preserves LM Studio @iq* quant suffixes", () => {
+      const resolved = resolveModelRefFromString({
+        raw: "lmstudio/qwen3.6-27b@iq3_xxs",
+        defaultProvider: "anthropic",
+      });
+      expect(resolved?.ref).toEqual({
+        provider: "lmstudio",
+        model: "qwen3.6-27b@iq3_xxs",
+      });
+    });
+
+    it("splits trailing profile suffix after LM Studio @iq* quant suffixes", () => {
+      const resolved = resolveModelRefFromString({
+        raw: "lmstudio/qwen3.6-27b@iq3_xxs@work",
+        defaultProvider: "anthropic",
+      });
+      expect(resolved?.ref).toEqual({
+        provider: "lmstudio",
+        model: "qwen3.6-27b@iq3_xxs",
+      });
+    });
+
     it("strips profile suffix before alias resolution", () => {
       const index = {
         byAlias: new Map([
diff --git a/src/auto-reply/model.test.ts b/src/auto-reply/model.test.ts
index 5352f892280f..c43e46bdc0e0 100644
--- a/src/auto-reply/model.test.ts
+++ b/src/auto-reply/model.test.ts
@@ -72,6 +72,20 @@ describe("extractModelDirective", () => {
       expect(result.rawProfile).toBe("cf:default");
     });
 
+    it("keeps LM Studio @iq* quant suffixes inside model ids", () => {
+      const result = extractModelDirective("/model lmstudio/qwen3.6-27b@iq3_xxs");
+      expect(result.hasDirective).toBe(true);
+      expect(result.rawModel).toBe("lmstudio/qwen3.6-27b@iq3_xxs");
+      expect(result.rawProfile).toBeUndefined();
+    });
+
+    it("allows profile overrides after LM Studio @iq* quant suffixes", () => {
+      const result = extractModelDirective("/model lmstudio/qwen3.6-27b@iq3_xxs@work");
+      expect(result.hasDirective).toBe(true);
+      expect(result.rawModel).toBe("lmstudio/qwen3.6-27b@iq3_xxs");
+      expect(result.rawProfile).toBe("work");
+    });
+
     it("returns no directive for plain text", () => {
       const result = extractModelDirective("hello world");
       expect(result.hasDirective).toBe(false);
diff --git a/src/plugins/providers.ts b/src/plugins/providers.ts
index 9528ba5dee96..ab1b41fc87e7 100644
--- a/src/plugins/providers.ts
+++ b/src/plugins/providers.ts
@@ -1,3 +1,4 @@
+import { splitTrailingAuthProfile } from "../agents/model-ref-profile.js";
 import { normalizeProviderId } from "../agents/provider-id.js";
 import { withBundledPluginVitestCompat } from "./bundled-compat.js";
 import { normalizePluginsConfig, resolveEffectivePluginActivationState } from "./config-state.js";
@@ -290,9 +291,7 @@ function resolveManifestRegistry(params: {
 }
 
 function stripModelProfileSuffix(value: string): string {
-  const trimmed = value.trim();
-  const at = trimmed.indexOf("@");
-  return at <= 0 ? trimmed : trimmed.slice(0, at).trim();
+  return splitTrailingAuthProfile(value).model;
 }
 
 function splitExplicitModelRef(rawModel: string): { provider?: string; modelId: string } | null {