diff --git a/pair-agent/SKILL.md b/pair-agent/SKILL.md
index 440495fa..6a7ddbbb 100644
--- a/pair-agent/SKILL.md
+++ b/pair-agent/SKILL.md
@@ -82,6 +82,14 @@ fi
 _ROUTING_DECLINED=$(~/.claude/skills/gstack/bin/gstack-config get routing_declined 2>/dev/null || echo "false")
 echo "HAS_ROUTING: $_HAS_ROUTING"
 echo "ROUTING_DECLINED: $_ROUTING_DECLINED"
+# Vendoring deprecation: detect if CWD has a vendored gstack copy
+_VENDORED="no"
+if [ -d ".claude/skills/gstack" ] && [ ! -L ".claude/skills/gstack" ]; then
+  if [ -f ".claude/skills/gstack/VERSION" ] || [ -d ".claude/skills/gstack/.git" ]; then
+    _VENDORED="yes"
+  fi
+fi
+echo "VENDORED_GSTACK: $_VENDORED"
 # Detect spawned session (OpenClaw or other orchestrator)
 [ -n "$OPENCLAW_SESSION" ] && echo "SPAWNED_SESSION: true" || true
 ```
@@ -210,6 +218,38 @@ Say "No problem. You can add routing rules later by running `gstack-config set r
 
 This only happens once per project. If `HAS_ROUTING` is `yes` or `ROUTING_DECLINED` is `true`, skip this entirely.
 
+If `VENDORED_GSTACK` is `yes`: This project has a vendored copy of gstack at
+`.claude/skills/gstack/`. Vendoring is deprecated. We will not keep vendored copies
+up to date, so this project's gstack will fall behind.
+
+Use AskUserQuestion (one-time per project, check for `~/.gstack/.vendoring-warned-$SLUG` marker):
+
+> This project has gstack vendored in `.claude/skills/gstack/`. Vendoring is deprecated.
+> We won't keep this copy up to date, so you'll fall behind on new features and fixes.
+>
+> Want to migrate to team mode? It takes about 30 seconds.
+
+Options:
+- A) Yes, migrate to team mode now
+- B) No, I'll handle it myself
+
+If A:
+1. Run `git rm -r .claude/skills/gstack/`
+2. Run `echo '.claude/skills/gstack/' >> .gitignore`
+3. Run `~/.claude/skills/gstack/bin/gstack-team-init required` (or `optional`)
+4. Run `git add .claude/ .gitignore CLAUDE.md && git commit -m "chore: migrate gstack from vendored to team mode"`
+5. Tell the user: "Done. Each developer now runs: `cd ~/.claude/skills/gstack && ./setup --team`"
+
+If B: say "OK, you're on your own to keep the vendored copy up to date."
+
+Always run (regardless of choice):
+```bash
+eval "$(~/.claude/skills/gstack/bin/gstack-slug 2>/dev/null)" 2>/dev/null || true
+touch ~/.gstack/.vendoring-warned-${SLUG:-unknown}
+```
+
+This only happens once per project. If the marker file exists, skip entirely.
+
 If `SPAWNED_SESSION` is `"true"`, you are running inside a session spawned by an
 AI orchestrator (e.g., OpenClaw). In spawned sessions:
 - Do NOT use AskUserQuestion for interactive prompts. Auto-choose the recommended option.