From 0d29b7978b86088d13b098937ce580382cf68ea1 Mon Sep 17 00:00:00 2001
From: "prompt.ac/@jeffrey" <mail@aesthetic.computer>
Date: Thu, 17 Sep 2026 17:40:56 -0700
Subject: [PATCH] Add read-only single-tab recording gate

---
 slab/captutor/lib/single-tab.mjs       | 14 ++++++++++++++
 slab/captutor/test/single-tab.test.mjs |  5 +++++
 2 files changed, 19 insertions(+)
 create mode 100644 slab/captutor/lib/single-tab.mjs
 create mode 100644 slab/captutor/test/single-tab.test.mjs

diff --git a/slab/captutor/lib/single-tab.mjs b/slab/captutor/lib/single-tab.mjs
new file mode 100644
index 000000000..5d8cf042d
--- /dev/null
+++ b/slab/captutor/lib/single-tab.mjs
@@ -0,0 +1,14 @@
+// Read-only recording gate: never close or navigate unrelated tabs.
+export async function assertSingleRecordingTab(cdp){
+ const current=await cdp.send('Browser.getWindowForTarget');
+ const {targetInfos}=await cdp.send('Target.getTargets');
+ if(!Array.isArray(targetInfos))throw Error('Cannot inspect recording-window tabs');
+ let count=0;
+ for(const t of targetInfos){
+  if(t.type!=='page')continue;
+  const {windowId}=await cdp.send('Browser.getWindowForTarget',{targetId:t.targetId});
+  if(windowId===current.windowId)count++;
+ }
+ if(count!==1)throw Error(`Recording window has ${count} tabs; move the project tab into its own window before recording. Preserve all other tabs.`);
+ return {windowId:current.windowId,tabCount:count};
+}
diff --git a/slab/captutor/test/single-tab.test.mjs b/slab/captutor/test/single-tab.test.mjs
new file mode 100644
index 000000000..43547194f
--- /dev/null
+++ b/slab/captutor/test/single-tab.test.mjs
@@ -0,0 +1,5 @@
+import test from 'node:test';import assert from 'node:assert/strict';import {assertSingleRecordingTab} from '../lib/single-tab.mjs';
+const mock=windows=>({send:async(method,p)=>{if(method==='Target.getTargets')return {targetInfos:windows.map((w,i)=>({type:'page',targetId:String(i)}))};if(method==='Browser.getWindowForTarget')return {windowId:p?.targetId===undefined?1:windows[Number(p.targetId)]};throw Error('Unexpected mutation '+method);}});
+test('one recording tab accepts other windows without mutation',async()=>assert.equal((await assertSingleRecordingTab(mock([1,2,2]))).tabCount,1));
+test('extra recording tab fails without closing it',async()=>assert.rejects(assertSingleRecordingTab(mock([1,1])),/2 tabs/));
+test('missing recording target fails closed',async()=>assert.rejects(assertSingleRecordingTab(mock([2])),/0 tabs/));
-- 
2.51.2