diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 39ce891..f22e4bb 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -146,3 +146,107 @@ jobs:
             echo "Expected symlink target '$EXPECTED', got '$LINK'"
             exit 1
           fi
+
+  test-only-tools-skips-skills:
+    name: only_tools=true installs tools but skips skills
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      # Write a Lucafile that defines both a tool and a skill.
+      - name: Create fixture Lucafile
+        run: |
+          cat > Lucafile <<'EOF'
+          ---
+          tools:
+            - name: yq
+              desiredBinaryName: yq
+              version: 4.52.4
+              url: https://github.com/mikefarah/yq/releases/download/v4.52.4/yq_darwin_arm64
+
+          agents:
+            - claude-code
+
+          skills:
+            - name: swift-concurrency
+              repository: AvdLee/Swift-Concurrency-Agent-Skill
+              version: 2.1.1
+
+          EOF
+
+      # only_tools defaults to "true", so --only-tools is passed to `luca install`.
+      - name: Setup Luca (only_tools default)
+        uses: ./
+        with:
+          spec: Lucafile
+
+      - name: Verify the tool was installed
+        run: |
+          YQ_VERSION=$(yq --version | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' | head -1)
+          if [ "$YQ_VERSION" != "4.52.4" ]; then
+            echo "Expected yq 4.52.4, got $YQ_VERSION"
+            exit 1
+          fi
+
+      - name: Verify the skill was NOT installed
+        run: |
+          if [ -e .luca/skills/swift-concurrency ]; then
+            echo ".luca/skills/swift-concurrency should not exist when only_tools=true"
+            exit 1
+          fi
+          if [ -e .claude/skills/swift-concurrency ]; then
+            echo ".claude/skills/swift-concurrency should not exist when only_tools=true"
+            exit 1
+          fi
+
+  test-only-tools-false-installs-skills:
+    name: only_tools=false installs both tools and skills
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      # Write a Lucafile that defines both a tool and a skill.
+      - name: Create fixture Lucafile
+        run: |
+          cat > Lucafile <<'EOF'
+          ---
+          tools:
+            - name: yq
+              desiredBinaryName: yq
+              version: 4.52.4
+              url: https://github.com/mikefarah/yq/releases/download/v4.52.4/yq_darwin_arm64
+
+          agents:
+            - claude-code
+
+          skills:
+            - name: swift-concurrency
+              repository: AvdLee/Swift-Concurrency-Agent-Skill
+              version: 2.1.1
+
+          EOF
+
+      - name: "Setup Luca (only_tools: false)"
+        uses: ./
+        with:
+          spec: Lucafile
+          only_tools: "false"
+
+      - name: Verify the tool was installed
+        run: |
+          YQ_VERSION=$(yq --version | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' | head -1)
+          if [ "$YQ_VERSION" != "4.52.4" ]; then
+            echo "Expected yq 4.52.4, got $YQ_VERSION"
+            exit 1
+          fi
+
+      - name: Verify the skill was installed
+        run: |
+          if [ ! -e .luca/skills/swift-concurrency ]; then
+            echo "Expected .luca/skills/swift-concurrency to exist"
+            exit 1
+          fi
+          if [ ! -e .claude/skills/swift-concurrency ]; then
+            echo "Expected .claude/skills/swift-concurrency to exist"
+            exit 1
+          fi
diff --git a/README.md b/README.md
index 8d40e9f..93a070a 100644
--- a/README.md
+++ b/README.md
@@ -52,6 +52,7 @@ On GitHub Enterprise the built-in `github.token` is scoped to your enterprise in
 |-------|-------------|----------|---------|
 | `version` | Luca version to install (e.g. `"1.2.3"`). Omit to use the latest release. | No | `""` (latest) |
 | `spec` | Path to the Luca spec file, relative to the workspace root. Omit to skip tool installation. | No | `""` (skip) |
+| `only_tools` | When `true`, passes `--only-tools` to `luca install`, installing tools only. Set to `false` to also install skills defined in the spec file. | No | `true` |
 | `github_token` | GitHub token for authenticating against the github.com API when downloading the Luca CLI. Defaults to the built-in `github.token`, which works on github.com. On GitHub Enterprise, pass a github.com PAT to avoid API rate limiting. | No | `""` (uses `github.token`) |
 
 When `spec` is provided, all tools listed in the spec file are added to `PATH` and available by name in subsequent steps.
diff --git a/action.yml b/action.yml
index b74a330..7669f5a 100644
--- a/action.yml
+++ b/action.yml
@@ -21,6 +21,12 @@ inputs:
       are installed and added to PATH. Omit to skip tool installation.
     required: false
     default: ""
+  only_tools:
+    description: >
+      When true (the default), passes `--only-tools` to `luca install`.
+      Set to false to install both tools and skills defined in the spec file.
+    required: false
+    default: "true"
   github_token:
     description: >
       A GitHub token used to authenticate against the github.com API when
@@ -48,5 +54,5 @@ runs:
       if: inputs.spec != ''
       shell: bash
       run: |
-        luca install --spec=${{ inputs.spec }}
+        luca install --spec=${{ inputs.spec }}${{ inputs.only_tools == 'true' && ' --only-tools' || '' }}
         echo "$GITHUB_WORKSPACE/.luca/tools" >> $GITHUB_PATH