fix: detect nested MoE configuration

Sources/SwiftLM/ModelProfiler.swift

@@ -204,6 +204,8 @@ enum ModelProfiler {
         let headDim: Int?
         let intermediateSize: Int?
         let vocabSize: Int?
+        let numExperts: Int?
+        let numExpertsPerTok: Int?
 
         enum CodingKeys: String, CodingKey {
             case numHiddenLayers = "num_hidden_layers"
@@ -213,6 +215,8 @@ enum ModelProfiler {
             case headDim = "head_dim"
             case intermediateSize = "intermediate_size"
             case vocabSize = "vocab_size"
+            case numExperts = "num_experts"
+            case numExpertsPerTok = "num_experts_per_tok"
         }
     }
 
@@ -252,9 +256,9 @@ enum ModelProfiler {
         let quantBits = config.quantizationConfig?.bits ?? detectQuantBits(modelId: modelId)
 
         // Detect MoE
-        let isMoE = config.numExperts != nil && (config.numExperts ?? 0) > 1
-        let numExperts = config.numExperts
-        let numActiveExperts = config.numExpertsPerTok
+        let numExperts = config.numExperts ?? config.textConfig?.numExperts
+        let numActiveExperts = config.numExpertsPerTok ?? config.textConfig?.numExpertsPerTok
+        let isMoE = (numExperts ?? 0) > 1
 
         // Measure weight file sizes on disk (only for MoE to avoid slow walks on dense models)
         let weightSize = isMoE ? measureWeightFiles(directory: modelDirectory) : 0

tests/SwiftLMTests/ModelProfilerTests.swift

@@ -0,0 +1,45 @@
+import Foundation
+import XCTest
+@testable import SwiftLM
+
+final class ModelProfilerTests: XCTestCase {
+    func testDetectsNestedQwenMoEConfiguration() throws {
+        let profile = try profile(json: """
+            {
+              "model_type": "qwen3_5_moe",
+              "text_config": {
+                "num_experts": 256,
+                "num_experts_per_tok": 8
+              }
+            }
+            """)
+
+        XCTAssertTrue(profile.isMoE)
+        XCTAssertEqual(profile.numExperts, 256)
+        XCTAssertEqual(profile.numActiveExperts, 8)
+    }
+
+    func testKeepsDetectingTopLevelLocalExperts() throws {
+        let profile = try profile(json: """
+            {
+              "model_type": "legacy_moe",
+              "num_local_experts": 64,
+              "num_experts_per_tok": 4
+            }
+            """)
+
+        XCTAssertTrue(profile.isMoE)
+        XCTAssertEqual(profile.numExperts, 64)
+        XCTAssertEqual(profile.numActiveExperts, 4)
+    }
+
+    private func profile(json: String) throws -> ModelProfile {
+        let directory = FileManager.default.temporaryDirectory
+            .appendingPathComponent(UUID().uuidString, isDirectory: true)
+        try FileManager.default.createDirectory(at: directory, withIntermediateDirectories: true)
+        defer { try? FileManager.default.removeItem(at: directory) }
+
+        try Data(json.utf8).write(to: directory.appendingPathComponent("config.json"))
+        return try XCTUnwrap(ModelProfiler.profile(modelDirectory: directory, modelId: "test-model"))
+    }
+}