diff --git a/.claude/hooks/devcontainer-policy-blocker.sh b/.claude/hooks/devcontainer-policy-blocker.sh
old mode 100644
new mode 100755
diff --git a/.github/workflows/template-integration.yml b/.github/workflows/template-integration.yml
new file mode 100644
index 0000000..4a4029e
--- /dev/null
+++ b/.github/workflows/template-integration.yml
@@ -0,0 +1,66 @@
+name: Template Integration Tests
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  unit-tests:
+    name: Unit Tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+      - name: Install test dependencies
+        run: pip install pytest
+      - name: Run unit tests
+        run: python -m pytest tests/ -v
+
+  integration-test:
+    name: Integration (${{ matrix.config-name }})
+    runs-on: ubuntu-latest
+    needs: unit-tests
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - config-name: mono-default
+            project-type: mono
+            packages: "core,server"
+            services: none
+          - config-name: mono-renamed
+            project-type: mono
+            packages: "engine,daemon"
+            services: none
+          - config-name: mono-extra-pkgs
+            project-type: mono
+            packages: "engine,lib:utils,daemon,worker"
+            services: none
+          - config-name: single-package
+            project-type: single
+            packages: "core,server"  # ignored by setup_project.py in single mode
+            services: none
+          - config-name: mono-postgres
+            project-type: mono
+            packages: "core,server"
+            services: postgres
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+      - uses: astral-sh/setup-uv@v5
+        with:
+          version: ">=0.5.0"
+      - name: Run template integration test
+        run: |
+          bash scripts/test_template_integration.sh \
+            --source-dir "$GITHUB_WORKSPACE" \
+            --work-dir "/tmp/test-${{ matrix.config-name }}" \
+            --project-type "${{ matrix.project-type }}" \
+            --packages "${{ matrix.packages }}" \
+            --services "${{ matrix.services }}"
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 14b3128..fe25f96 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -8,6 +8,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Added
+- Template integration CI pipeline (`template-integration.yml`) tests `setup_project.py` across 5 configurations (mono-default, mono-renamed, mono-extra-pkgs, single-package, mono-postgres) -- verifies each produces a valid project that installs, lints, type-checks, and passes tests
+- Reusable `scripts/test_template_integration.sh` for local template validation with the same 9-step verification as CI
 - Workflow skill `/sync` checks workspace readiness before starting work (git fetch, status, branch info, warnings)
 - Workflow skill `/design` crystallizes brainstorming into structured plans with conflict detection against DECISIONS.md
 - Workflow skill `/done` auto-detects scope (Q/S/P) and runs the full validate-ship-document pipeline, including the former `/ship` checklist
diff --git a/docs/DECISIONS.md b/docs/DECISIONS.md
index 5b3c5fd..37fd667 100644
--- a/docs/DECISIONS.md
+++ b/docs/DECISIONS.md
@@ -113,6 +113,19 @@ When a decision is superseded or obsolete, delete it (git history preserves the
 - `/sync` and `/done` have `disable-model-invocation: true` (side effects: git fetch, git commit/push, PR creation); `/design` is intentionally model-invocable so Claude can suggest it during brainstorming
 - QSP paths (Q/S/P) and their step descriptions preserved in DEVELOPMENT_PROCESS.md -- skills orchestrate the paths, they don't replace them
 
+## 2026-03-10: Template Integration CI Pipeline
+
+**Request**: Create a CI pipeline that applies the template in various settings to catch template bugs before merge.
+
+**Decisions**:
+- New workflow `template-integration.yml` (not extending `tests.yml`) -- `tests.yml` has `{{base_branch}}` in its trigger and never fires on the raw template repo
+- GitHub Actions matrix (5 configs) + reusable shell script (`scripts/test_template_integration.sh`) -- matrix defines WHAT to test, script defines HOW to verify; script also runnable locally
+- Copy template to temp dir before applying -- `setup_project.py` modifies in-place, would destroy the checkout
+- 5 matrix configs cover all major code paths: default monorepo, package renaming, additional packages, single-package conversion, Docker Compose services
+- Unit tests gate job runs first -- fail fast if setup_project.py functions are broken before spending matrix resources
+- Placeholder check uses named pattern matching (`{{project_name}}` etc.) not generic `{{` -- avoids false positives from GitHub Actions `${{ }}` expressions
+- `test_setup_project.py` excluded from integration pytest runs -- tests setup script internals (already covered by unit-tests job), fails on single-package layout
+
 ## 2026-03-04: Devcontainer Permission Tiers
 
 **Request**: Expand Claude Code permissions for devcontainer usage, taking advantage of container isolation (firewall, non-root user, hooks) to reduce unnecessary permission prompts.
diff --git a/scripts/test_template_integration.sh b/scripts/test_template_integration.sh
new file mode 100644
index 0000000..203c60e
--- /dev/null
+++ b/scripts/test_template_integration.sh
@@ -0,0 +1,249 @@
+#!/usr/bin/env bash
+# Template integration test: apply setup_project.py with a given configuration
+# and verify the resulting project builds, lints, type-checks, and passes tests.
+#
+# Usage:
+#   scripts/test_template_integration.sh \
+#     --source-dir /path/to/template \
+#     --work-dir /tmp/test-project \
+#     --project-type mono \
+#     --packages "core,server" \
+#     --services none
+
+set -euo pipefail
+
+# ---------------------------------------------------------------------------
+# Argument parsing
+# ---------------------------------------------------------------------------
+SOURCE_DIR=""
+WORK_DIR=""
+PROJECT_TYPE="mono"
+PACKAGES="core,server"
+SERVICES="none"
+
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        --source-dir)  SOURCE_DIR="$2";  shift 2 ;;
+        --work-dir)    WORK_DIR="$2";    shift 2 ;;
+        --project-type) PROJECT_TYPE="$2"; shift 2 ;;
+        --packages)    PACKAGES="$2";    shift 2 ;;
+        --services)    SERVICES="$2";    shift 2 ;;
+        --help|-h)
+            echo "Usage: $0 --source-dir DIR --work-dir DIR [--project-type mono|single] [--packages LIST] [--services none|postgres|postgres-redis|custom]"
+            exit 0
+            ;;
+        *)
+            echo "Unknown argument: $1" >&2
+            exit 1
+            ;;
+    esac
+done
+
+if [[ -z "$SOURCE_DIR" || -z "$WORK_DIR" ]]; then
+    echo "ERROR: --source-dir and --work-dir are required" >&2
+    exit 1
+fi
+
+# Guard against rm -rf on dangerous paths (/, $HOME, source dir).
+RESOLVED_WORK=$(cd "$SOURCE_DIR" 2>/dev/null && pwd)  # resolve SOURCE_DIR for comparison
+RESOLVED_SRC="$RESOLVED_WORK"
+case "$WORK_DIR" in
+    /|"$HOME"|"$RESOLVED_SRC")
+        echo "ERROR: --work-dir '$WORK_DIR' is unsafe (matches /, \$HOME, or --source-dir)" >&2
+        exit 1
+        ;;
+esac
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+step_pass() { echo "  [PASS] $1"; }
+step_fail() { echo "  [FAIL] $1" >&2; exit 1; }
+
+# ---------------------------------------------------------------------------
+# Banner
+# ---------------------------------------------------------------------------
+echo "=== Template Integration Test ==="
+echo "  type=$PROJECT_TYPE  packages=$PACKAGES  services=$SERVICES"
+echo "  source: $SOURCE_DIR"
+echo "  work:   $WORK_DIR"
+echo ""
+
+# ---------------------------------------------------------------------------
+# Step 1: Copy template to work directory
+# ---------------------------------------------------------------------------
+echo "Step 1: Copy template to work directory"
+rm -rf "$WORK_DIR"
+mkdir -p "$WORK_DIR"
+
+# Use rsync if available, otherwise fall back to cp + cleanup
+if command -v rsync > /dev/null 2>&1; then
+    rsync -a \
+        --exclude='.git' \
+        --exclude='.venv' \
+        --exclude='__pycache__' \
+        --exclude='.coverage' \
+        --exclude='.ruff_cache' \
+        --exclude='.pytest_cache' \
+        --exclude='node_modules' \
+        "$SOURCE_DIR/" "$WORK_DIR/"
+else
+    cp -a "$SOURCE_DIR/." "$WORK_DIR/"
+    rm -rf "$WORK_DIR/.git" "$WORK_DIR/.venv" "$WORK_DIR/node_modules"
+    find "$WORK_DIR" -type d -name '__pycache__' -exec rm -rf {} + 2>/dev/null || true
+    find "$WORK_DIR" -type d -name '.ruff_cache' -exec rm -rf {} + 2>/dev/null || true
+    find "$WORK_DIR" -type d -name '.pytest_cache' -exec rm -rf {} + 2>/dev/null || true
+fi
+step_pass "Copied template"
+
+# ---------------------------------------------------------------------------
+# Step 2: Apply template
+# ---------------------------------------------------------------------------
+echo "Step 2: Apply template (setup_project.py)"
+python "$WORK_DIR/setup_project.py" \
+    --name test-project \
+    --namespace test_project \
+    --description "CI integration test" \
+    --author "CI Bot" \
+    --email "ci@test.com" \
+    --python-version 3.11 \
+    --base-branch main \
+    --type "$PROJECT_TYPE" \
+    --packages "$PACKAGES" \
+    --services "$SERVICES" \
+    --keep-setup \
+|| step_fail "setup_project.py exited with non-zero status"
+step_pass "Template applied"
+
+# ---------------------------------------------------------------------------
+# Step 3: Verify no remaining placeholders
+# ---------------------------------------------------------------------------
+echo "Step 3: Check for remaining template placeholders"
+# All subsequent steps run inside $WORK_DIR (uv sync/run need the project root as cwd).
+cd "$WORK_DIR"
+
+# Search for actual template placeholders (not GitHub Actions ${{ }} expressions).
+# The pattern matches {{word}} but NOT ${{word}} (GHA syntax).
+# Excludes setup_project.py (defines them) and test files (reference them in fixtures).
+PLACEHOLDER_PATTERN='\{\{(project_name|namespace|description|author_name|author_email|python_version|base_branch|year)\}\}'
+PLACEHOLDER_HITS=$(grep -rE "$PLACEHOLDER_PATTERN" \
+    --include='*.py' --include='*.toml' --include='*.yml' --include='*.yaml' \
+    --include='*.md' --include='*.json' --include='*.cfg' --include='*.ini' \
+    --include='*.txt' --include='*.sh' \
+    --exclude='setup_project.py' \
+    --exclude='test_setup_project.py' \
+    --exclude='test_template_integration.sh' \
+    . 2>/dev/null || true)
+
+if [[ -n "$PLACEHOLDER_HITS" ]]; then
+    echo "$PLACEHOLDER_HITS"
+    step_fail "Found remaining template placeholders"
+fi
+step_pass "No remaining placeholders"
+
+# ---------------------------------------------------------------------------
+# Step 4: Verify directory structure
+# ---------------------------------------------------------------------------
+echo "Step 4: Verify directory structure"
+if [[ "$PROJECT_TYPE" == "single" ]]; then
+    [[ -d "src/test_project" ]] || step_fail "src/test_project/ missing"
+    [[ ! -d "libs" ]]          || step_fail "libs/ should not exist in single-package mode"
+    [[ ! -d "apps" ]]          || step_fail "apps/ should not exist in single-package mode"
+    step_pass "Single-package layout correct"
+else
+    [[ -d "libs" ]] || step_fail "libs/ missing"
+    [[ -d "apps" ]] || step_fail "apps/ missing"
+    # Verify each requested package exists in the expected directory.
+    # setup_project.py treats the first unlabeled package as a lib, subsequent
+    # unlabeled ones as apps. lib: and app: prefixes override this.
+    FIRST_UNLABELED=true
+    IFS=',' read -ra PKG_LIST <<< "$PACKAGES"
+    for pkg in "${PKG_LIST[@]}"; do
+        pkg=$(echo "$pkg" | xargs)  # trim whitespace
+        if [[ "$pkg" == lib:* ]]; then
+            pkg_name="${pkg#lib:}"
+            [[ -d "libs/$pkg_name" ]] || step_fail "libs/$pkg_name/ missing (from lib:$pkg_name)"
+        elif [[ "$pkg" == app:* ]]; then
+            pkg_name="${pkg#app:}"
+            [[ -d "apps/$pkg_name" ]] || step_fail "apps/$pkg_name/ missing (from app:$pkg_name)"
+        elif $FIRST_UNLABELED; then
+            FIRST_UNLABELED=false
+            [[ -d "libs/$pkg" ]] || step_fail "libs/$pkg/ missing (first package defaults to lib)"
+        else
+            [[ -d "apps/$pkg" ]] || step_fail "apps/$pkg/ missing (subsequent packages default to app)"
+        fi
+    done
+    step_pass "Monorepo layout correct (all packages present)"
+fi
+
+# ---------------------------------------------------------------------------
+# Step 5: Install dependencies
+# ---------------------------------------------------------------------------
+echo "Step 5: Install dependencies (uv sync)"
+if [[ "$PROJECT_TYPE" == "single" ]]; then
+    uv sync --group dev || step_fail "uv sync failed"
+else
+    uv sync --all-packages --group dev || step_fail "uv sync failed"
+fi
+step_pass "Dependencies installed"
+
+# ---------------------------------------------------------------------------
+# Step 6: Lint
+# ---------------------------------------------------------------------------
+echo "Step 6: Lint (ruff)"
+uv run ruff check . || step_fail "ruff check failed"
+uv run ruff format --check . || step_fail "ruff format check failed"
+step_pass "Lint passed"
+
+# ---------------------------------------------------------------------------
+# Step 7: Type check
+# ---------------------------------------------------------------------------
+echo "Step 7: Type check (pyright)"
+uv run pyright || step_fail "pyright failed"
+step_pass "Type check passed"
+
+# ---------------------------------------------------------------------------
+# Step 8: Run tests (pytest)
+# ---------------------------------------------------------------------------
+echo "Step 8: Run tests (pytest)"
+# Run package tests only (not root tests/ which contains template meta-tests
+# already covered by the unit-tests CI job).
+if [[ "$PROJECT_TYPE" == "single" ]]; then
+    uv run pytest tests/ -v --tb=short --ignore=tests/test_setup_project.py \
+        || step_fail "pytest failed"
+else
+    uv run pytest libs/ apps/ tests/ -v --tb=short --ignore=tests/test_setup_project.py \
+        || step_fail "pytest failed"
+fi
+step_pass "Tests passed"
+
+# ---------------------------------------------------------------------------
+# Step 9: Verify services (if applicable)
+# ---------------------------------------------------------------------------
+if [[ "$SERVICES" != "none" ]]; then
+    echo "Step 9: Verify docker-compose.yml"
+    COMPOSE_FILE=".devcontainer/docker-compose.yml"
+    [[ -f "$COMPOSE_FILE" ]] || step_fail "$COMPOSE_FILE missing"
+    grep -q 'services:' "$COMPOSE_FILE" \
+        || step_fail "$COMPOSE_FILE missing 'services:' key"
+    # Verify the requested service is actually defined (db for postgres profiles).
+    case "$SERVICES" in
+        postgres)
+            grep -q '  db:' "$COMPOSE_FILE" \
+                || step_fail "$COMPOSE_FILE missing 'db' service for --services postgres"
+            ;;
+        postgres-redis)
+            grep -q '  db:' "$COMPOSE_FILE" \
+                || step_fail "$COMPOSE_FILE missing 'db' service for --services postgres-redis"
+            grep -q '  redis:' "$COMPOSE_FILE" \
+                || step_fail "$COMPOSE_FILE missing 'redis' service for --services postgres-redis"
+            ;;
+    esac
+    step_pass "docker-compose.yml present with expected services"
+fi
+
+# ---------------------------------------------------------------------------
+# Done
+# ---------------------------------------------------------------------------
+echo ""
+echo "=== All checks passed ==="
diff --git a/tests/test_hooks.py b/tests/test_hooks.py
index 2586364..544c486 100644
--- a/tests/test_hooks.py
+++ b/tests/test_hooks.py
@@ -18,7 +18,11 @@
     "test-on-change.sh",
 ]
 
-ALL_HOOKS = SECURITY_HOOKS + PRODUCTIVITY_HOOKS
+DEVCONTAINER_HOOKS = [
+    "devcontainer-policy-blocker.sh",
+]
+
+ALL_HOOKS = SECURITY_HOOKS + PRODUCTIVITY_HOOKS + DEVCONTAINER_HOOKS
 
 
 class TestHookExistence: