diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5ba476a6..35a7d06e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ permissions:
 
 jobs:
   test-macos:
-    name: Swift ${{ matrix.swift }} on macOS ${{ matrix.macos }} with Xcode ${{ matrix.xcode }}
+    name: Swift ${{ matrix.swift }} on macOS ${{ matrix.macos }} with Xcode ${{ matrix.xcode }}${{ matrix.traits != '' && format(' and --traits {0}', matrix.traits) || '' }}
     runs-on: macos-${{ matrix.macos }}
     env:
       DEVELOPER_DIR: "/Applications/Xcode_${{ matrix.xcode }}.app/Contents/Developer"
@@ -23,56 +23,82 @@ jobs:
           - macos: "15"
             swift: "6.1"
             xcode: "16.3"
+            traits: ""
+          - macos: "15"
+            swift: "6.1"
+            xcode: "16.3"
+            traits: "AsyncHTTPClient"
+          - macos: "26"
+            swift: "6.2"
+            xcode: "26.0"
+            traits: ""
           - macos: "26"
             swift: "6.2"
             xcode: "26.0"
+            traits: "AsyncHTTPClient"
     timeout-minutes: 10
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Cache Swift Package Manager dependencies
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: |
             ~/.cache/org.swift.swiftpm
             .build
-          key: ${{ runner.os }}-swift-${{ matrix.swift }}-spm-${{ hashFiles('**/Package.resolved') }}
+          key: ${{ runner.os }}-swift-${{ matrix.swift }}-${{ matrix.traits == '' && 'ahc-off' || 'ahc-on' }}-spm-${{ hashFiles('Package.swift', 'Package.resolved') }}
           restore-keys: |
-            ${{ runner.os }}-swift-${{ matrix.swift }}-spm-
+            ${{ runner.os }}-swift-${{ matrix.swift }}-${{ matrix.traits == '' && 'ahc-off' || 'ahc-on' }}-spm-
 
       - name: Lint
         run: swift format lint --strict --recursive .
 
       - name: Build
-        run: swift build --build-tests --traits MLX,Llama,CoreML
+        run: swift build --build-tests --traits MLX,Llama,CoreML${{ matrix.traits != '' && format(',{0}', matrix.traits) || '' }}
 
       - name: Test
-        run: swift test --skip-build
+        run: swift test --skip-build --traits MLX,Llama,CoreML${{ matrix.traits != '' && format(',{0}', matrix.traits) || '' }}
 
   test-linux:
-    name: Swift ${{ matrix.swift-version }} on Linux
+    name: Swift ${{ matrix.swift }} on Linux${{ matrix.traits != '' && format(' and --traits {0}', matrix.traits) || '' }}
     runs-on: ubuntu-latest
+    container: swift:${{ matrix.swift }}
     strategy:
       fail-fast: false
       matrix:
-        swift-version:
-          - 6.1.0
+        include:
+          - swift: "6.1.3"
+            traits: ""
+          # Temporary workaround: Skip AsyncHTTPClient on Linux Swift 6.1
+          # due to toolchain linker failure in libswiftObservation.so (undefined swift::threading::fatal).
+          # Keep AsyncHTTPClient coverage on Linux Swift 6.2 and re-enable here once fixed upstream.
+          # - swift: "6.1.3"
+          #   traits: "AsyncHTTPClient"
+          - swift: "6.2.4"
+            traits: ""
+          - swift: "6.2.4"
+            traits: "AsyncHTTPClient"
     timeout-minutes: 10
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
-      - name: Setup Swift
-        uses: vapor/swiftly-action@v0.2
+      - name: Cache Swift Package Manager dependencies
+        uses: actions/cache@v5
         with:
-          toolchain: ${{ matrix.swift-version }}
+          path: |
+            ~/.cache/org.swift.swiftpm
+            .build
+          key: ${{ runner.os }}-swift-${{ matrix.swift }}-${{ matrix.traits == '' && 'ahc-off' || 'ahc-on' }}-spm-${{ hashFiles('Package.swift', 'Package.resolved') }}
+          restore-keys: |
+            ${{ runner.os }}-swift-${{ matrix.swift }}-${{ matrix.traits == '' && 'ahc-off' || 'ahc-on' }}-spm-
 
       - name: Lint
         run: swift format lint --strict --recursive .
 
       - name: Build
-        run: swift build
+        run: swift build${{ matrix.traits != '' && format(' --traits {0}', matrix.traits) || '' }}
 
       - name: Test
-        run: swift test
+        run: swift test${{ matrix.traits != '' && format(' --traits {0}', matrix.traits) || '' }}
diff --git a/Tests/AnyLanguageModelTests/InstructionsTests.swift b/Tests/AnyLanguageModelTests/InstructionsTests.swift
index d43daf41..eb326d74 100644
--- a/Tests/AnyLanguageModelTests/InstructionsTests.swift
+++ b/Tests/AnyLanguageModelTests/InstructionsTests.swift
@@ -16,7 +16,7 @@ struct InstructionsTests {
     }
 
     @Test func builderCombinesLines() throws {
-        let instructions = try Instructions {
+        let instructions = Instructions {
             "First line"
             "Second line"
         }
@@ -28,7 +28,7 @@ struct InstructionsTests {
         let includeConditional = true
         let includeOptional = false
 
-        let instructions = try Instructions {
+        let instructions = Instructions {
             "Always"
             if includeConditional {
                 "Conditional"