diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 8b83613da..67ca0cfbd 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -41,3 +41,49 @@ jobs:
                       ./themes/*.zsh-theme; do
             zsh -n "$file" || return 1
           done
+
+      - name: Focused syntax check for bootstrap-adjacent touched files
+        if: github.event_name == 'pull_request'
+        run: |
+          mapfile -t touched < <(
+            git diff --name-only "${{ github.event.pull_request.base.sha }}" "${{ github.sha }}" \
+            | grep -E '^(lib/bootstrap\.zsh|lib/tests/bootstrap.*\.zsh|oh-my-zsh\.sh|lib/(completion|compfix|functions|theme-and-appearance)\.zsh|plugins/.+/.+\.plugin\.zsh|themes/.+\.zsh-theme)$' \
+            || true
+          )
+
+          if [ "${#touched[@]}" -eq 0 ]; then
+            echo "No bootstrap-adjacent files touched"
+            exit 0
+          fi
+
+          for file in "${touched[@]}"; do
+            echo "Syntax checking $file"
+            zsh -n "$file"
+          done
+
+      - name: Run bootstrap unit test
+        if: github.event_name == 'pull_request'
+        run: zsh ./lib/tests/bootstrap.test.zsh
+
+      - name: Run inline bootstrap invariants smoke test
+        if: github.event_name == 'pull_request'
+        run: zsh ./lib/tests/bootstrap-inline-ci.test.zsh
+
+  plugin-manager-smoke:
+    name: Plugin manager smoke (${{ matrix.manager }}:${{ matrix.scenario }})
+    runs-on: ubuntu-latest
+    if: github.repository == 'ohmyzsh/ohmyzsh' && github.event_name == 'pull_request'
+    strategy:
+      fail-fast: false
+      matrix:
+        manager: [antigen, zinit]
+        scenario: [positive, negative]
+    steps:
+      - name: Set up git repository
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - name: Install zsh
+        run: sudo apt-get update; sudo apt-get install zsh
+
+      - name: Run plugin-manager bootstrap integration
+        run: zsh ./lib/tests/plugin-manager-bootstrap-integration.test.zsh "${{ matrix.manager }}" "${{ matrix.scenario }}"
diff --git a/.github/workflows/plugin-manager-nightly.yml b/.github/workflows/plugin-manager-nightly.yml
new file mode 100644
index 000000000..134603e1d
--- /dev/null
+++ b/.github/workflows/plugin-manager-nightly.yml
@@ -0,0 +1,37 @@
+name: Plugin manager integration (advisory)
+
+on:
+  schedule:
+    - cron: '0 6 * * *'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  plugin-manager-matrix:
+    name: ${{ matrix.manager }}:${{ matrix.scenario }}
+    runs-on: ubuntu-latest
+    if: github.repository == 'ohmyzsh/ohmyzsh'
+    continue-on-error: true
+    strategy:
+      fail-fast: false
+      matrix:
+        manager: [antigen, zinit, zgen, zplug, antibody, zulu]
+        scenario: [positive, negative]
+
+    steps:
+      - name: Set up git repository
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+
+      - name: Install zsh and go
+        run: sudo apt-get update; sudo apt-get install zsh golang
+
+      - name: Run plugin-manager bootstrap integration
+        run: zsh ./lib/tests/plugin-manager-bootstrap-integration.test.zsh "${{ matrix.manager }}" "${{ matrix.scenario }}"
+
+      - name: Rollout note
+        if: always()
+        run: |
+          echo "Phase 2 active: full manager matrix is advisory/nightly."
+          echo "Phase 3 target: promote full matrix to required after stability window."
diff --git a/lib/tests/bootstrap-inline-ci.test.zsh b/lib/tests/bootstrap-inline-ci.test.zsh
new file mode 100755
index 000000000..1dc48a1f9
--- /dev/null
+++ b/lib/tests/bootstrap-inline-ci.test.zsh
@@ -0,0 +1,35 @@
+#!/usr/bin/zsh -df
+
+set -eu
+
+bootstrap_file="${0:A:h:h}/bootstrap.zsh"
+
+assert() {
+  local condition="$1" message="$2"
+  if ! eval "$condition"; then
+    print -u2 "\e[31mError\e[0m: $message"
+    exit 1
+  fi
+}
+
+tmp==(:)
+mkdir -p "$tmp/ohmyzsh"/{functions,completions,cache} "$tmp/ohmyzsh/custom"/{functions,completions}
+
+export ZSH="$tmp/ohmyzsh"
+unset ZSH_CUSTOM ZSH_CACHE_DIR OMZ_IS_BOOTSTRAPPED
+fpath=()
+
+source "$bootstrap_file"
+
+assert '[[ "$OMZ_IS_BOOTSTRAPPED" == true ]]' "OMZ bootstrap signal should be true"
+assert '[[ -d "$ZSH_CACHE_DIR/completions" ]]' "cache completions directory should exist"
+assert '[[ "${fpath[(Ie)$ZSH/functions]}" -gt 0 ]]' "fpath should include OMZ functions"
+assert '[[ "${fpath[(Ie)$ZSH/completions]}" -gt 0 ]]' "fpath should include OMZ completions"
+assert '[[ "${fpath[(Ie)$ZSH_CUSTOM/functions]}" -gt 0 ]]' "fpath should include custom functions"
+assert '[[ "${fpath[(Ie)$ZSH_CUSTOM/completions]}" -gt 0 ]]' "fpath should include custom completions"
+assert '[[ "${fpath[(Ie)$ZSH_CACHE_DIR/completions]}" -gt 0 ]]' "fpath should include cache completions"
+
+touch "$ZSH_CACHE_DIR/completions/_bootstrap_ci_smoke"
+assert '[[ -f "$ZSH_CACHE_DIR/completions/_bootstrap_ci_smoke" ]]' "completion cache write should succeed"
+
+print -u2 "\e[32mSuccess\e[0m bootstrap inline invariants"
diff --git a/lib/tests/plugin-manager-bootstrap-integration.test.zsh b/lib/tests/plugin-manager-bootstrap-integration.test.zsh
new file mode 100755
index 000000000..5ce834ef0
--- /dev/null
+++ b/lib/tests/plugin-manager-bootstrap-integration.test.zsh
@@ -0,0 +1,101 @@
+#!/usr/bin/zsh -df
+
+set -euo pipefail
+
+if (( $# != 2 )); then
+  print -u2 "Usage: $0 <manager> <positive|negative>"
+  exit 1
+fi
+
+manager="$1"
+scenario="$2"
+
+if [[ "$scenario" != "positive" && "$scenario" != "negative" ]]; then
+  print -u2 "scenario must be 'positive' or 'negative'"
+  exit 1
+fi
+
+repo_root="${0:A:h:h:h}"
+tmp==(:)
+workspace="$tmp/workspace"
+home_dir="$tmp/home"
+cache_dir="$tmp/cache"
+zshrc="$tmp/.zshrc"
+
+mkdir -p "$workspace" "$home_dir" "$cache_dir"
+
+manager_install=''
+manager_source=''
+
+case "$manager" in
+  antigen)
+    manager_install='git clone https://github.com/zsh-users/antigen.git "$MANAGER_HOME/antigen" >/dev/null 2>&1'
+    manager_source='source "$MANAGER_HOME/antigen/antigen.zsh"'
+    ;;
+  zinit)
+    manager_install='git clone https://github.com/zdharma-continuum/zinit.git "$MANAGER_HOME/zinit" >/dev/null 2>&1'
+    manager_source='source "$MANAGER_HOME/zinit/zinit.zsh"'
+    ;;
+  zgen)
+    manager_install='git clone https://github.com/tarjoilija/zgen.git "$MANAGER_HOME/zgen" >/dev/null 2>&1'
+    manager_source='source "$MANAGER_HOME/zgen/zgen.zsh"'
+    ;;
+  zplug)
+    manager_install='git clone https://github.com/zplug/zplug "$MANAGER_HOME/zplug" >/dev/null 2>&1'
+    manager_source='export ZPLUG_HOME="$MANAGER_HOME/zplug"; source "$ZPLUG_HOME/init.zsh"'
+    ;;
+  antibody)
+    manager_install='command -v go >/dev/null 2>&1; export GOBIN="$MANAGER_HOME/bin"; mkdir -p "$GOBIN"; go install github.com/getantibody/antibody@latest >/dev/null 2>&1'
+    manager_source='"$MANAGER_HOME/bin/antibody" --version >/dev/null 2>&1'
+    ;;
+  zulu)
+    manager_install='git clone https://github.com/zulu-zsh/zulu.git "$MANAGER_HOME/zulu" >/dev/null 2>&1'
+    manager_source='source "$MANAGER_HOME/zulu/zulu.zsh"'
+    ;;
+  *)
+    print -u2 "Unsupported manager: $manager"
+    exit 1
+    ;;
+esac
+
+cat > "$zshrc" <<RC
+set -euo pipefail
+
+export HOME="$home_dir"
+export XDG_CACHE_HOME="$cache_dir"
+export OMZ_ROOT="$repo_root"
+export ZSH="\$OMZ_ROOT"
+export MANAGER_HOME="$workspace/$manager"
+mkdir -p "\$MANAGER_HOME"
+
+$manager_install
+$manager_source
+RC
+
+if [[ "$scenario" == "positive" ]]; then
+  cat >> "$zshrc" <<'RC'
+source "$OMZ_ROOT/lib/bootstrap.zsh"
+[[ "${OMZ_IS_BOOTSTRAPPED:-}" == true ]] || { print -u2 "bootstrap signal missing before OMZ load"; return 1; }
+RC
+else
+  cat >> "$zshrc" <<'RC'
+[[ -z "${OMZ_IS_BOOTSTRAPPED:-}" ]] || { print -u2 "bootstrap signal unexpectedly set without hook"; return 1; }
+source "$OMZ_ROOT/lib/bootstrap.zsh"
+RC
+fi
+
+cat >> "$zshrc" <<RC
+[[ "\${OMZ_IS_BOOTSTRAPPED:-}" == true ]] || { print -u2 "bootstrap signal not set before OMZ entrypoint sourcing"; return 1; }
+
+source "\$OMZ_ROOT/lib/functions.zsh"
+source "\$OMZ_ROOT/plugins/git/git.plugin.zsh"
+source "\$OMZ_ROOT/themes/robbyrussell.zsh-theme"
+
+[[ -d "\$ZSH_CACHE_DIR/completions" ]] || { print -u2 "completions cache directory missing"; return 1; }
+
+touch "\$ZSH_CACHE_DIR/completions/_ci_${manager}_${scenario}" || { print -u2 "completion cache write failed"; return 1; }
+[[ -f "\$ZSH_CACHE_DIR/completions/_ci_${manager}_${scenario}" ]] || { print -u2 "completion cache file missing"; return 1; }
+RC
+
+zsh -df "$zshrc"
+print -u2 "\e[32mSuccess\e[0m $manager $scenario"