diff --git a/SKILL.md b/SKILL.md
index 258a7e4a..bb065fbc 100644
--- a/SKILL.md
+++ b/SKILL.md
@@ -80,6 +80,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -206,6 +214,38 @@ 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.
+
 ## Voice
 
 **Tone:** direct, concrete, sharp, never corporate, never academic. Sound like a builder, not a consultant. Name the file, the function, the command. No filler, no throat-clearing.
diff --git a/autoplan/SKILL.md b/autoplan/SKILL.md
index bcfb6224..39600cc4 100644
--- a/autoplan/SKILL.md
+++ b/autoplan/SKILL.md
@@ -90,6 +90,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -216,6 +224,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/benchmark/SKILL.md b/benchmark/SKILL.md
index 156ae8cf..36acde51 100644
--- a/benchmark/SKILL.md
+++ b/benchmark/SKILL.md
@@ -83,6 +83,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -209,6 +217,38 @@ 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.
+
 ## Voice
 
 **Tone:** direct, concrete, sharp, never corporate, never academic. Sound like a builder, not a consultant. Name the file, the function, the command. No filler, no throat-clearing.
diff --git a/browse/SKILL.md b/browse/SKILL.md
index d224b309..16e0bf92 100644
--- a/browse/SKILL.md
+++ b/browse/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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -208,6 +216,38 @@ 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.
+
 ## Voice
 
 **Tone:** direct, concrete, sharp, never corporate, never academic. Sound like a builder, not a consultant. Name the file, the function, the command. No filler, no throat-clearing.
diff --git a/canary/SKILL.md b/canary/SKILL.md
index e7153e93..47f90a64 100644
--- a/canary/SKILL.md
+++ b/canary/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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -208,6 +216,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/checkpoint/SKILL.md b/checkpoint/SKILL.md
index 2967f14c..5c38062f 100644
--- a/checkpoint/SKILL.md
+++ b/checkpoint/SKILL.md
@@ -85,6 +85,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -211,6 +219,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/codex/SKILL.md b/codex/SKILL.md
index 5706dd8c..ac34d85e 100644
--- a/codex/SKILL.md
+++ b/codex/SKILL.md
@@ -84,6 +84,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/cso/SKILL.md b/cso/SKILL.md
index 20efe14b..3ebe8f19 100644
--- a/cso/SKILL.md
+++ b/cso/SKILL.md
@@ -87,6 +87,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -213,6 +221,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/design-consultation/SKILL.md b/design-consultation/SKILL.md
index 92067d74..83f1ec7b 100644
--- a/design-consultation/SKILL.md
+++ b/design-consultation/SKILL.md
@@ -87,6 +87,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -213,6 +221,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/design-html/SKILL.md b/design-html/SKILL.md
index c50b37ed..a77611a1 100644
--- a/design-html/SKILL.md
+++ b/design-html/SKILL.md
@@ -89,6 +89,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -215,6 +223,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/design-review/SKILL.md b/design-review/SKILL.md
index 9b78080e..3b5fcd09 100644
--- a/design-review/SKILL.md
+++ b/design-review/SKILL.md
@@ -87,6 +87,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -213,6 +221,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/design-shotgun/SKILL.md b/design-shotgun/SKILL.md
index 7de41cf3..70bb16c6 100644
--- a/design-shotgun/SKILL.md
+++ b/design-shotgun/SKILL.md
@@ -84,6 +84,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/devex-review/SKILL.md b/devex-review/SKILL.md
index 18ba792f..2d368ada 100644
--- a/devex-review/SKILL.md
+++ b/devex-review/SKILL.md
@@ -87,6 +87,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -213,6 +221,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/document-release/SKILL.md b/document-release/SKILL.md
index a4f2617e..d482c436 100644
--- a/document-release/SKILL.md
+++ b/document-release/SKILL.md
@@ -84,6 +84,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/health/SKILL.md b/health/SKILL.md
index ee42db1f..7747a94a 100644
--- a/health/SKILL.md
+++ b/health/SKILL.md
@@ -84,6 +84,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/investigate/SKILL.md b/investigate/SKILL.md
index f69914a1..6cf5a58c 100644
--- a/investigate/SKILL.md
+++ b/investigate/SKILL.md
@@ -99,6 +99,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -225,6 +233,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/land-and-deploy/SKILL.md b/land-and-deploy/SKILL.md
index b1e75902..a9706c10 100644
--- a/land-and-deploy/SKILL.md
+++ b/land-and-deploy/SKILL.md
@@ -81,6 +81,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -207,6 +215,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/learn/SKILL.md b/learn/SKILL.md
index 9afca4c4..f351ff61 100644
--- a/learn/SKILL.md
+++ b/learn/SKILL.md
@@ -84,6 +84,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/office-hours/SKILL.md b/office-hours/SKILL.md
index c3cceba3..fb8a6e85 100644
--- a/office-hours/SKILL.md
+++ b/office-hours/SKILL.md
@@ -91,6 +91,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -217,6 +225,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/open-gstack-browser/SKILL.md b/open-gstack-browser/SKILL.md
index 31757899..f45deda6 100644
--- a/open-gstack-browser/SKILL.md
+++ b/open-gstack-browser/SKILL.md
@@ -81,6 +81,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -207,6 +215,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/plan-ceo-review/SKILL.md b/plan-ceo-review/SKILL.md
index 4d1253cb..5a45b7f0 100644
--- a/plan-ceo-review/SKILL.md
+++ b/plan-ceo-review/SKILL.md
@@ -87,6 +87,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -213,6 +221,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/plan-design-review/SKILL.md b/plan-design-review/SKILL.md
index b0f7f3a6..b0600ed1 100644
--- a/plan-design-review/SKILL.md
+++ b/plan-design-review/SKILL.md
@@ -85,6 +85,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -211,6 +219,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/plan-devex-review/SKILL.md b/plan-devex-review/SKILL.md
index e954f737..d5a865e6 100644
--- a/plan-devex-review/SKILL.md
+++ b/plan-devex-review/SKILL.md
@@ -89,6 +89,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -215,6 +223,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/plan-eng-review/SKILL.md b/plan-eng-review/SKILL.md
index de21a370..77bd4b24 100644
--- a/plan-eng-review/SKILL.md
+++ b/plan-eng-review/SKILL.md
@@ -87,6 +87,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -213,6 +221,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/qa-only/SKILL.md b/qa-only/SKILL.md
index e49088c7..8ad0c2cf 100644
--- a/qa-only/SKILL.md
+++ b/qa-only/SKILL.md
@@ -83,6 +83,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -209,6 +217,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/qa/SKILL.md b/qa/SKILL.md
index 06e23e6f..4c3e59ed 100644
--- a/qa/SKILL.md
+++ b/qa/SKILL.md
@@ -89,6 +89,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -215,6 +223,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/retro/SKILL.md b/retro/SKILL.md
index 6b059aee..a3c17e95 100644
--- a/retro/SKILL.md
+++ b/retro/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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -208,6 +216,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/review/SKILL.md b/review/SKILL.md
index b16de752..4284e427 100644
--- a/review/SKILL.md
+++ b/review/SKILL.md
@@ -85,6 +85,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -211,6 +219,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/setup-browser-cookies/SKILL.md b/setup-browser-cookies/SKILL.md
index 549c4d25..db608234 100644
--- a/setup-browser-cookies/SKILL.md
+++ b/setup-browser-cookies/SKILL.md
@@ -79,6 +79,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -205,6 +213,38 @@ 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.
+
 ## Voice
 
 **Tone:** direct, concrete, sharp, never corporate, never academic. Sound like a builder, not a consultant. Name the file, the function, the command. No filler, no throat-clearing.
diff --git a/setup-deploy/SKILL.md b/setup-deploy/SKILL.md
index 0dfd1df4..06c55330 100644
--- a/setup-deploy/SKILL.md
+++ b/setup-deploy/SKILL.md
@@ -85,6 +85,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -211,6 +219,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
diff --git a/ship/SKILL.md b/ship/SKILL.md
index 25afbb03..e1384af5 100644
--- a/ship/SKILL.md
+++ b/ship/SKILL.md
@@ -86,6 +86,14 @@ 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"
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills AND do not
@@ -212,6 +220,38 @@ 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.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.