diff --git a/README.md b/README.md
index a0d9c40e3..3d6eff08f 100644
--- a/README.md
+++ b/README.md
@@ -445,11 +445,11 @@ gstack includes **opt-in** usage telemetry to help improve the project. Here's e
 - **On first run,** gstack asks if you want to share anonymous usage data. You can say no.
 - **What's sent (if you opt in):** skill name, duration, success/fail, gstack version, OS. That's it.
 - **What's never sent:** code, file paths, repo names, branch names, prompts, or any user-generated content.
-- **Change anytime:** `gstack-config set telemetry off` disables everything instantly.
+- **Change anytime:** `gstack-config set telemetry off` disables remote telemetry plus local analytics and session-tracking artifacts instantly.
 
 Data is stored in [Supabase](https://supabase.com) (open source Firebase alternative). The schema is in [`supabase/migrations/`](supabase/migrations/) — you can verify exactly what's collected. The Supabase publishable key in the repo is a public key (like a Firebase API key) — row-level security policies deny all direct access. Telemetry flows through validated edge functions that enforce schema checks, event type allowlists, and field length limits.
 
-**Local analytics are always available.** Run `gstack-analytics` to see your personal usage dashboard from the local JSONL file — no remote data needed.
+**Local analytics are available when telemetry is enabled.** Run `gstack-analytics` to see your personal usage dashboard from the local JSONL file — no remote data needed.
 
 ## Troubleshooting
 
diff --git a/bin/gstack-spawned-session-status b/bin/gstack-spawned-session-status
new file mode 100755
index 000000000..8f646661f
--- /dev/null
+++ b/bin/gstack-spawned-session-status
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# gstack-spawned-session-status — emit SPAWNED_SESSION when running under an orchestrator
+#
+# Keeps orchestrator-specific env var names (e.g. OPENCLAW_SESSION) out of every
+# generated SKILL.md preamble, so security scanners that match on those strings
+# in shell-init scripts don't flag a stock gstack install. See issue #1150.
+set -euo pipefail
+
+if [ -n "${OPENCLAW_SESSION:-}" ]; then
+  echo "SPAWNED_SESSION: true"
+fi
diff --git a/scripts/resolvers/preamble/generate-completion-status.ts b/scripts/resolvers/preamble/generate-completion-status.ts
index 0c50da1c7..109f25fd9 100644
--- a/scripts/resolvers/preamble/generate-completion-status.ts
+++ b/scripts/resolvers/preamble/generate-completion-status.ts
@@ -62,19 +62,19 @@ Run this bash:
 \`\`\`bash
 _TEL_END=$(date +%s)
 _TEL_DUR=$(( _TEL_END - _TEL_START ))
+if [ "$_TEL" != "off" ]; then
 rm -f ~/.gstack/analytics/.pending-"$_SESSION_ID" 2>/dev/null || true
 # Session timeline: record skill completion (local-only, never sent anywhere)
 ~/.claude/skills/gstack/bin/gstack-timeline-log '{"skill":"SKILL_NAME","event":"completed","branch":"'$(git branch --show-current 2>/dev/null || echo unknown)'","outcome":"OUTCOME","duration_s":"'"$_TEL_DUR"'","session":"'"$_SESSION_ID"'"}' 2>/dev/null || true
-# Local analytics (gated on telemetry setting)
-if [ "$_TEL" != "off" ]; then
+# Local analytics
 echo '{"skill":"SKILL_NAME","duration_s":"'"$_TEL_DUR"'","outcome":"OUTCOME","browse":"USED_BROWSE","session":"'"$_SESSION_ID"'","ts":"'$(date -u +%Y-%m-%dT%H:%M:%SZ)'"}' >> ~/.gstack/analytics/skill-usage.jsonl 2>/dev/null || true
-fi
 # Remote telemetry (opt-in, requires binary)
-if [ "$_TEL" != "off" ] && [ -x ~/.claude/skills/gstack/bin/gstack-telemetry-log ]; then
+if [ -x ~/.claude/skills/gstack/bin/gstack-telemetry-log ]; then
   ~/.claude/skills/gstack/bin/gstack-telemetry-log \\
     --skill "SKILL_NAME" --duration "$_TEL_DUR" --outcome "OUTCOME" \\
     --used-browse "USED_BROWSE" --session-id "$_SESSION_ID" 2>/dev/null &
 fi
+fi
 \`\`\`
 
 Replace \`SKILL_NAME\`, \`OUTCOME\`, and \`USED_BROWSE\` before running.
diff --git a/scripts/resolvers/preamble/generate-preamble-bash.ts b/scripts/resolvers/preamble/generate-preamble-bash.ts
index d8552421a..3acc27546 100644
--- a/scripts/resolvers/preamble/generate-preamble-bash.ts
+++ b/scripts/resolvers/preamble/generate-preamble-bash.ts
@@ -18,10 +18,6 @@ GSTACK_DESIGN="$GSTACK_ROOT/design/dist"
 \`\`\`bash
 ${runtimeRoot}_UPD=$(${ctx.paths.binDir}/gstack-update-check 2>/dev/null || ${ctx.paths.localSkillRoot}/bin/gstack-update-check 2>/dev/null || true)
 [ -n "$_UPD" ] && echo "$_UPD" || true
-mkdir -p ~/.gstack/sessions
-touch ~/.gstack/sessions/"$PPID"
-_SESSIONS=$(find ~/.gstack/sessions -mmin -120 -type f 2>/dev/null | wc -l | tr -d ' ')
-find ~/.gstack/sessions -mmin +120 -type f -exec rm {} + 2>/dev/null || true
 _PROACTIVE=$(${ctx.paths.binDir}/gstack-config get proactive 2>/dev/null || echo "true")
 _PROACTIVE_PROMPTED=$([ -f ~/.gstack/.proactive-prompted ] && echo "yes" || echo "no")
 _BRANCH=$(git branch --show-current 2>/dev/null || echo "unknown")
@@ -41,24 +37,31 @@ _TEL_START=$(date +%s)
 _SESSION_ID="$$-$(date +%s)"
 echo "TELEMETRY: \${_TEL:-off}"
 echo "TEL_PROMPTED: $_TEL_PROMPTED"
+if [ "$_TEL" != "off" ]; then
+mkdir -p ~/.gstack/sessions
+touch ~/.gstack/sessions/"$PPID"
+_SESSIONS=$(find ~/.gstack/sessions -mmin -120 -type f 2>/dev/null | wc -l | tr -d ' ')
+find ~/.gstack/sessions -mmin +120 -type f -exec rm {} + 2>/dev/null || true
+fi
 _EXPLAIN_LEVEL=$(${ctx.paths.binDir}/gstack-config get explain_level 2>/dev/null || echo "default")
 if [ "$_EXPLAIN_LEVEL" != "default" ] && [ "$_EXPLAIN_LEVEL" != "terse" ]; then _EXPLAIN_LEVEL="default"; fi
 echo "EXPLAIN_LEVEL: $_EXPLAIN_LEVEL"
 _QUESTION_TUNING=$(${ctx.paths.binDir}/gstack-config get question_tuning 2>/dev/null || echo "false")
 echo "QUESTION_TUNING: $_QUESTION_TUNING"
-mkdir -p ~/.gstack/analytics
 if [ "$_TEL" != "off" ]; then
+mkdir -p ~/.gstack/analytics
 echo '{"skill":"${ctx.skillName}","ts":"'$(date -u +%Y-%m-%dT%H:%M:%SZ)'","repo":"'$(_repo=$(basename "$(git rev-parse --show-toplevel 2>/dev/null)" 2>/dev/null | tr -cd 'a-zA-Z0-9._-'); echo "\${_repo:-unknown}")'"}'  >> ~/.gstack/analytics/skill-usage.jsonl 2>/dev/null || true
-fi
+# zsh-compatible: use find instead of glob to avoid NOMATCH error
 for _PF in $(find ~/.gstack/analytics -maxdepth 1 -name '.pending-*' 2>/dev/null); do
   if [ -f "$_PF" ]; then
-    if [ "$_TEL" != "off" ] && [ -x "${ctx.paths.binDir}/gstack-telemetry-log" ]; then
+    if [ -x "${ctx.paths.binDir}/gstack-telemetry-log" ]; then
       ${ctx.paths.binDir}/gstack-telemetry-log --event-type skill_run --skill _pending_finalize --outcome unknown --session-id "$_SESSION_ID" 2>/dev/null || true
     fi
     rm -f "$_PF" 2>/dev/null || true
   fi
   break
 done
+fi
 eval "$(${ctx.paths.binDir}/gstack-slug 2>/dev/null)" 2>/dev/null || true
 _LEARN_FILE="\${GSTACK_HOME:-$HOME/.gstack}/projects/\${SLUG:-unknown}/learnings.jsonl"
 if [ -f "$_LEARN_FILE" ]; then
@@ -70,7 +73,9 @@ if [ -f "$_LEARN_FILE" ]; then
 else
   echo "LEARNINGS: 0"
 fi
+if [ "$_TEL" != "off" ]; then
 ${ctx.paths.binDir}/gstack-timeline-log '{"skill":"${ctx.skillName}","event":"started","branch":"'"$_BRANCH"'","session":"'"$_SESSION_ID"'"}' 2>/dev/null &
+fi
 _HAS_ROUTING="no"
 if [ -f CLAUDE.md ] && grep -q "## Skill routing" CLAUDE.md 2>/dev/null; then
   _HAS_ROUTING="yes"
@@ -103,7 +108,7 @@ else
   export GSTACK_PLAN_MODE="inactive"
 fi
 echo "GSTACK_PLAN_MODE: $GSTACK_PLAN_MODE"
-[ -n "$OPENCLAW_SESSION" ] && echo "SPAWNED_SESSION: true" || true${ctx.host === 'gbrain' || ctx.host === 'hermes' ? `
+${ctx.paths.binDir}/gstack-spawned-session-status 2>/dev/null || true${ctx.host === 'gbrain' || ctx.host === 'hermes' ? `
 if command -v gbrain &>/dev/null; then
   _BRAIN_JSON=$(gbrain doctor --fast --json 2>/dev/null || echo '{}')
   _BRAIN_SCORE=$(echo "$_BRAIN_JSON" | grep -o '"health_score":[0-9]*' | cut -d: -f2)
diff --git a/test/gen-skill-docs.test.ts b/test/gen-skill-docs.test.ts
index ffe6ed7d6..fcc8733a3 100644
--- a/test/gen-skill-docs.test.ts
+++ b/test/gen-skill-docs.test.ts
@@ -2575,6 +2575,15 @@ describe('telemetry', () => {
     expect(content).toContain('PLAN MODE EXCEPTION');
   });
 
+  test('generated SKILL.md gates session tracking and timeline on telemetry', () => {
+    const content = fs.readFileSync(path.join(ROOT, 'SKILL.md'), 'utf-8');
+    expect(content).toContain('if [ "$_TEL" != "off" ]; then');
+    expect(content).toContain('mkdir -p ~/.gstack/sessions');
+    expect(content).toContain('gstack-timeline-log');
+    expect(content).not.toContain('OPENCLAW_SESSION');
+    expect(content).toContain('gstack-spawned-session-status');
+  });
+
   test('generated SKILL.md contains pending marker handling', () => {
     const content = fs.readFileSync(path.join(ROOT, 'SKILL.md'), 'utf-8');
     expect(content).toContain('.pending');
diff --git a/test/telemetry.test.ts b/test/telemetry.test.ts
index 96bdf54c7..fe0e638d1 100644
--- a/test/telemetry.test.ts
+++ b/test/telemetry.test.ts
@@ -242,6 +242,17 @@ describe('gstack-telemetry-log', () => {
   });
 });
 
+describe('gstack-spawned-session-status', () => {
+  test('is silent when no spawned-session env var is set', () => {
+    expect(run(`${BIN}/gstack-spawned-session-status`)).toBe('');
+  });
+
+  test('emits SPAWNED_SESSION when OPENCLAW_SESSION is present', () => {
+    expect(run(`${BIN}/gstack-spawned-session-status`, { OPENCLAW_SESSION: '1' }))
+      .toBe('SPAWNED_SESSION: true');
+  });
+});
+
 describe('.pending marker', () => {
   test('finalizes stale .pending from another session as outcome:unknown', () => {
     setConfig('telemetry', 'anonymous');
@@ -398,23 +409,32 @@ describe('gstack-community-dashboard', () => {
 });
 
 describe('preamble telemetry gating (#467)', () => {
-  test('preamble source does not write JSONL unconditionally', () => {
-    const preamble = fs.readFileSync(path.join(ROOT, 'scripts', 'resolvers', 'preamble.ts'), 'utf-8');
-    const lines = preamble.split('\n');
-    for (let i = 0; i < lines.length; i++) {
-      if (lines[i].includes('skill-usage.jsonl') && lines[i].includes('>>')) {
-        // Each JSONL write must be inside a _TEL conditional (within 5 lines above)
-        let foundConditional = false;
-        for (let j = i - 1; j >= Math.max(0, i - 5); j--) {
-          if (lines[j].includes('_TEL') && lines[j].includes('off')) {
-            foundConditional = true;
-            break;
-          }
-        }
-        if (!foundConditional) {
-          throw new Error(`Unconditional JSONL write at preamble.ts line ${i + 1}: ${lines[i].trim()}`);
-        }
-      }
-    }
+  test('preamble source gates local tracking artifacts on telemetry', () => {
+    const preamble = fs.readFileSync(
+      path.join(ROOT, 'scripts', 'resolvers', 'preamble', 'generate-preamble-bash.ts'),
+      'utf-8',
+    );
+    expect(preamble).toMatch(/if \[ "\$_TEL" != "off" \]; then\nmkdir -p ~\/\.gstack\/sessions/);
+    expect(preamble).toMatch(/if \[ "\$_TEL" != "off" \]; then\nmkdir -p ~\/\.gstack\/analytics/);
+    expect(preamble).toMatch(/if \[ "\$_TEL" != "off" \]; then\n\$\{ctx\.paths\.binDir\}\/gstack-timeline-log/);
+  });
+
+  test('completion status gates local timeline and analytics on telemetry', () => {
+    const completion = fs.readFileSync(
+      path.join(ROOT, 'scripts', 'resolvers', 'preamble', 'generate-completion-status.ts'),
+      'utf-8',
+    );
+    expect(completion).toMatch(/if \[ "\$_TEL" != "off" \]; then\nrm -f ~\/\.gstack\/analytics\/\.pending-/);
+    expect(completion).toContain('if [ "$_TEL" != "off" ]; then');
+    expect(completion).toContain('gstack-timeline-log');
+  });
+
+  test('preamble source uses helper binary instead of OPENCLAW_SESSION directly', () => {
+    const preamble = fs.readFileSync(
+      path.join(ROOT, 'scripts', 'resolvers', 'preamble', 'generate-preamble-bash.ts'),
+      'utf-8',
+    );
+    expect(preamble).toContain('gstack-spawned-session-status');
+    expect(preamble).not.toContain('OPENCLAW_SESSION');
   });
 });