diff --git a/bin/gstack-team-init b/bin/gstack-team-init
index 6195c7b6..1fc08ea9 100755
--- a/bin/gstack-team-init
+++ b/bin/gstack-team-init
@@ -29,6 +29,26 @@ REPO_ROOT=$(git rev-parse --show-toplevel)
 CLAUDE_MD="$REPO_ROOT/CLAUDE.md"
 GENERATED=()
 
+# ── Migrate vendored copy if present ──────────────────────────
+
+if [ -d "$REPO_ROOT/.claude/skills/gstack" ] && [ ! -L "$REPO_ROOT/.claude/skills/gstack" ]; then
+  if [ -f "$REPO_ROOT/.claude/skills/gstack/VERSION" ] || [ -d "$REPO_ROOT/.claude/skills/gstack/.git" ]; then
+    echo "  Found vendored gstack copy at $REPO_ROOT/.claude/skills/gstack"
+    echo "  Team mode uses the global install — removing vendored copy..."
+    ( cd "$REPO_ROOT" && git rm -r --cached .claude/skills/gstack/ 2>/dev/null ) || true
+    if [ -f "$REPO_ROOT/.gitignore" ]; then
+      if ! grep -qF '.claude/skills/gstack/' "$REPO_ROOT/.gitignore" 2>/dev/null; then
+        echo '.claude/skills/gstack/' >> "$REPO_ROOT/.gitignore"
+      fi
+    else
+      echo '.claude/skills/gstack/' > "$REPO_ROOT/.gitignore"
+    fi
+    rm -rf "$REPO_ROOT/.claude/skills/gstack"
+    GENERATED+=(".gitignore")
+    echo "  Removed vendored copy and added .claude/skills/gstack/ to .gitignore"
+  fi
+fi
+
 # ── CLAUDE.md snippet ──────────────────────────────────────────
 
 if [ "$MODE" = "optional" ]; then
diff --git a/gstack-upgrade/SKILL.md b/gstack-upgrade/SKILL.md
index 12c3840a..07fe7519 100644
--- a/gstack-upgrade/SKILL.md
+++ b/gstack-upgrade/SKILL.md
@@ -137,9 +137,9 @@ cd "$INSTALL_DIR" && ./setup
 rm -rf "$INSTALL_DIR.bak" "$TMP_DIR"
 ```
 
-### Step 4.5: Sync local vendored copy
+### Step 4.5: Handle local vendored copy
 
-Use the install directory from Step 2. Check if there's also a local vendored copy that needs updating:
+Use the install directory from Step 2. Check if there's also a local vendored copy, and whether team mode is active:
 
 ```bash
 _ROOT=$(git rev-parse --show-toplevel 2>/dev/null)
@@ -151,10 +151,24 @@ if [ -n "$_ROOT" ] && [ -d "$_ROOT/.claude/skills/gstack" ]; then
     LOCAL_GSTACK="$_ROOT/.claude/skills/gstack"
   fi
 fi
+_TEAM_MODE=$(~/.claude/skills/gstack/bin/gstack-config get team_mode 2>/dev/null || echo "false")
 echo "LOCAL_GSTACK=$LOCAL_GSTACK"
+echo "TEAM_MODE=$_TEAM_MODE"
 ```
 
-If `LOCAL_GSTACK` is non-empty, update it by copying from the freshly-upgraded primary install (same approach as README vendored install):
+**If `LOCAL_GSTACK` is non-empty AND `TEAM_MODE` is `true`:** Remove the vendored copy. Team mode uses the global install as the single source of truth.
+
+```bash
+cd "$_ROOT"
+git rm -r --cached .claude/skills/gstack/ 2>/dev/null || true
+if ! grep -qF '.claude/skills/gstack/' .gitignore 2>/dev/null; then
+  echo '.claude/skills/gstack/' >> .gitignore
+fi
+rm -rf "$LOCAL_GSTACK"
+```
+Tell user: "Removed vendored copy at `$LOCAL_GSTACK` (team mode active — global install is the source of truth). Commit the `.gitignore` change when ready."
+
+**If `LOCAL_GSTACK` is non-empty AND `TEAM_MODE` is NOT `true`:** Update it by copying from the freshly-upgraded primary install (same approach as README vendored install):
 ```bash
 mv "$LOCAL_GSTACK" "$LOCAL_GSTACK.bak"
 cp -Rf "$INSTALL_DIR" "$LOCAL_GSTACK"
@@ -243,11 +257,13 @@ Use the output to determine if an upgrade is available.
 
 3. If no output (primary is up to date): check for a stale local vendored copy.
 
-Run the Step 2 bash block above to detect the primary install type and directory (`INSTALL_TYPE` and `INSTALL_DIR`). Then run the Step 4.5 detection bash block above to check for a local vendored copy (`LOCAL_GSTACK`).
+Run the Step 2 bash block above to detect the primary install type and directory (`INSTALL_TYPE` and `INSTALL_DIR`). Then run the Step 4.5 detection bash block above to check for a local vendored copy (`LOCAL_GSTACK`) and team mode status (`TEAM_MODE`).
 
 **If `LOCAL_GSTACK` is empty** (no local vendored copy): tell the user "You're already on the latest version (v{version})."
 
-**If `LOCAL_GSTACK` is non-empty**, compare versions:
+**If `LOCAL_GSTACK` is non-empty AND `TEAM_MODE` is `true`:** Remove the vendored copy using the Step 4.5 team-mode removal bash block above. Tell user: "Global v{version} is up to date. Removed stale vendored copy (team mode active). Commit the `.gitignore` change when ready."
+
+**If `LOCAL_GSTACK` is non-empty AND `TEAM_MODE` is NOT `true`**, compare versions:
 ```bash
 PRIMARY_VER=$(cat "$INSTALL_DIR/VERSION" 2>/dev/null || echo "unknown")
 LOCAL_VER=$(cat "$LOCAL_GSTACK/VERSION" 2>/dev/null || echo "unknown")
diff --git a/gstack-upgrade/SKILL.md.tmpl b/gstack-upgrade/SKILL.md.tmpl
index 9e85478a..af4bcd23 100644
--- a/gstack-upgrade/SKILL.md.tmpl
+++ b/gstack-upgrade/SKILL.md.tmpl
@@ -139,9 +139,9 @@ cd "$INSTALL_DIR" && ./setup
 rm -rf "$INSTALL_DIR.bak" "$TMP_DIR"
 ```
 
-### Step 4.5: Sync local vendored copy
+### Step 4.5: Handle local vendored copy
 
-Use the install directory from Step 2. Check if there's also a local vendored copy that needs updating:
+Use the install directory from Step 2. Check if there's also a local vendored copy, and whether team mode is active:
 
 ```bash
 _ROOT=$(git rev-parse --show-toplevel 2>/dev/null)
@@ -153,10 +153,24 @@ if [ -n "$_ROOT" ] && [ -d "$_ROOT/.claude/skills/gstack" ]; then
     LOCAL_GSTACK="$_ROOT/.claude/skills/gstack"
   fi
 fi
+_TEAM_MODE=$(~/.claude/skills/gstack/bin/gstack-config get team_mode 2>/dev/null || echo "false")
 echo "LOCAL_GSTACK=$LOCAL_GSTACK"
+echo "TEAM_MODE=$_TEAM_MODE"
 ```
 
-If `LOCAL_GSTACK` is non-empty, update it by copying from the freshly-upgraded primary install (same approach as README vendored install):
+**If `LOCAL_GSTACK` is non-empty AND `TEAM_MODE` is `true`:** Remove the vendored copy. Team mode uses the global install as the single source of truth.
+
+```bash
+cd "$_ROOT"
+git rm -r --cached .claude/skills/gstack/ 2>/dev/null || true
+if ! grep -qF '.claude/skills/gstack/' .gitignore 2>/dev/null; then
+  echo '.claude/skills/gstack/' >> .gitignore
+fi
+rm -rf "$LOCAL_GSTACK"
+```
+Tell user: "Removed vendored copy at `$LOCAL_GSTACK` (team mode active — global install is the source of truth). Commit the `.gitignore` change when ready."
+
+**If `LOCAL_GSTACK` is non-empty AND `TEAM_MODE` is NOT `true`:** Update it by copying from the freshly-upgraded primary install (same approach as README vendored install):
 ```bash
 mv "$LOCAL_GSTACK" "$LOCAL_GSTACK.bak"
 cp -Rf "$INSTALL_DIR" "$LOCAL_GSTACK"
@@ -245,11 +259,13 @@ Use the output to determine if an upgrade is available.
 
 3. If no output (primary is up to date): check for a stale local vendored copy.
 
-Run the Step 2 bash block above to detect the primary install type and directory (`INSTALL_TYPE` and `INSTALL_DIR`). Then run the Step 4.5 detection bash block above to check for a local vendored copy (`LOCAL_GSTACK`).
+Run the Step 2 bash block above to detect the primary install type and directory (`INSTALL_TYPE` and `INSTALL_DIR`). Then run the Step 4.5 detection bash block above to check for a local vendored copy (`LOCAL_GSTACK`) and team mode status (`TEAM_MODE`).
 
 **If `LOCAL_GSTACK` is empty** (no local vendored copy): tell the user "You're already on the latest version (v{version})."
 
-**If `LOCAL_GSTACK` is non-empty**, compare versions:
+**If `LOCAL_GSTACK` is non-empty AND `TEAM_MODE` is `true`:** Remove the vendored copy using the Step 4.5 team-mode removal bash block above. Tell user: "Global v{version} is up to date. Removed stale vendored copy (team mode active). Commit the `.gitignore` change when ready."
+
+**If `LOCAL_GSTACK` is non-empty AND `TEAM_MODE` is NOT `true`**, compare versions:
 ```bash
 PRIMARY_VER=$(cat "$INSTALL_DIR/VERSION" 2>/dev/null || echo "unknown")
 LOCAL_VER=$(cat "$LOCAL_GSTACK/VERSION" 2>/dev/null || echo "unknown")
diff --git a/setup b/setup
index 65da9496..ca97764d 100755
--- a/setup
+++ b/setup
@@ -785,6 +785,7 @@ HOOK_CMD="$SOURCE_GSTACK_DIR/bin/gstack-session-update"
 
 if [ "$TEAM_MODE" -eq 1 ]; then
   "$GSTACK_CONFIG" set auto_upgrade true 2>/dev/null || true
+  "$GSTACK_CONFIG" set team_mode true 2>/dev/null || true
 
   # Register SessionStart hook in Claude Code settings
   if [ -x "$SETTINGS_HOOK" ]; then
@@ -802,6 +803,7 @@ fi
 
 if [ "$NO_TEAM_MODE" -eq 1 ]; then
   "$GSTACK_CONFIG" set auto_upgrade false 2>/dev/null || true
+  "$GSTACK_CONFIG" set team_mode false 2>/dev/null || true
 
   # Remove SessionStart hook from Claude Code settings
   if [ -x "$SETTINGS_HOOK" ]; then
diff --git a/test/team-mode.test.ts b/test/team-mode.test.ts
index e2b030fb..660f6687 100644
--- a/test/team-mode.test.ts
+++ b/test/team-mode.test.ts
@@ -257,6 +257,69 @@ describe('gstack-team-init', () => {
     const matches = claude.match(/## gstack/g);
     expect(matches).toHaveLength(1);
   });
+
+  test('removes vendored copy when present', () => {
+    // Create a fake vendored gstack with VERSION file
+    const vendoredDir = path.join(tmpDir, '.claude', 'skills', 'gstack');
+    fs.mkdirSync(vendoredDir, { recursive: true });
+    fs.writeFileSync(path.join(vendoredDir, 'VERSION'), '0.14.0.0');
+    fs.writeFileSync(path.join(vendoredDir, 'README.md'), 'vendored');
+    // Track it in git
+    execSync('git add .claude/skills/gstack/', { cwd: tmpDir });
+    execSync('git commit -m "add vendored gstack"', { cwd: tmpDir });
+
+    const result = run(`${TEAM_INIT} optional`, { cwd: tmpDir });
+    expect(result.exitCode).toBe(0);
+    expect(result.stdout).toContain('Found vendored gstack copy');
+    expect(result.stdout).toContain('Removed vendored copy');
+    // Vendored dir should be gone
+    expect(fs.existsSync(vendoredDir)).toBe(false);
+    // .gitignore should have the entry
+    const gitignore = fs.readFileSync(path.join(tmpDir, '.gitignore'), 'utf-8');
+    expect(gitignore).toContain('.claude/skills/gstack/');
+  });
+
+  test('skips when no vendored copy present', () => {
+    const result = run(`${TEAM_INIT} optional`, { cwd: tmpDir });
+    expect(result.exitCode).toBe(0);
+    expect(result.stdout).not.toContain('Found vendored gstack copy');
+  });
+
+  test('skips when .claude/skills/gstack is a symlink', () => {
+    // Create a symlink (not a real vendored copy)
+    const skillsDir = path.join(tmpDir, '.claude', 'skills');
+    fs.mkdirSync(skillsDir, { recursive: true });
+    const targetDir = mkTmpDir();
+    fs.writeFileSync(path.join(targetDir, 'VERSION'), '0.14.0.0');
+    fs.symlinkSync(targetDir, path.join(skillsDir, 'gstack'));
+
+    const result = run(`${TEAM_INIT} optional`, { cwd: tmpDir });
+    expect(result.exitCode).toBe(0);
+    expect(result.stdout).not.toContain('Found vendored gstack copy');
+    // Symlink should still exist
+    expect(fs.lstatSync(path.join(skillsDir, 'gstack')).isSymbolicLink()).toBe(true);
+    fs.rmSync(targetDir, { recursive: true, force: true });
+  });
+
+  test('does not duplicate .gitignore entry on re-run', () => {
+    // Create vendored copy
+    const vendoredDir = path.join(tmpDir, '.claude', 'skills', 'gstack');
+    fs.mkdirSync(vendoredDir, { recursive: true });
+    fs.writeFileSync(path.join(vendoredDir, 'VERSION'), '0.14.0.0');
+    execSync('git add .claude/skills/gstack/', { cwd: tmpDir });
+    execSync('git commit -m "add vendored"', { cwd: tmpDir });
+
+    run(`${TEAM_INIT} optional`, { cwd: tmpDir });
+
+    // Re-create vendored dir to simulate re-run scenario
+    fs.mkdirSync(vendoredDir, { recursive: true });
+    fs.writeFileSync(path.join(vendoredDir, 'VERSION'), '0.14.0.0');
+    run(`${TEAM_INIT} optional`, { cwd: tmpDir });
+
+    const gitignore = fs.readFileSync(path.join(tmpDir, '.gitignore'), 'utf-8');
+    const matches = gitignore.match(/\.claude\/skills\/gstack\//g);
+    expect(matches).toHaveLength(1);
+  });
 });
 
 describe('setup --team / --no-team / -q', () => {