diff --git a/easel/desktop/build-status.cjs b/easel/desktop/build-status.cjs
index 7646e5c809..5aabe35104 100644
--- a/easel/desktop/build-status.cjs
+++ b/easel/desktop/build-status.cjs
@@ -10,7 +10,8 @@ function devStatus(running,state){
 function createBuildStatus({app,devHome,root,send,onDevReady,channel=app.isPackaged?'release':'local'}){
   let running=devHome?JSON.parse(fs.readFileSync(path.join(root,'../build.json'))):null;
   let latest={channel,version:app.getVersion(),status:'unknown'};
-  let requested='',timer;
+  let requested='',timer,pin='';
+  if(devHome){const dir=path.join(devHome,'running');fs.mkdirSync(dir,{recursive:true});pin=path.join(dir,process.pid+'.json');fs.writeFileSync(pin,JSON.stringify({pid:process.pid,tree:running.tree}));process.once('exit',()=>{try{fs.unlinkSync(pin);}catch{}});}
   const emit=()=>send('build-status',latest);
   function poll(){
     if(!devHome)return emit();
@@ -25,6 +26,6 @@ function createBuildStatus({app,devHome,root,send,onDevReady,channel=app.isPacka
     }catch{latest={...latest,status:'unknown'};emit();}
   }
   if(devHome){timer=setInterval(poll,3000);timer.unref();}
-  return {poll,emit,release(status,info={}){if(!devHome){latest={...latest,status,latest:info.version||latest.latest,checkedAt:new Date().toISOString()};emit();}},adopt(nextRoot){running=JSON.parse(fs.readFileSync(path.join(nextRoot,'../build.json')));requested='';poll();},close(){clearInterval(timer);}};
+  return {poll,emit,release(status,info={}){if(!devHome){latest={...latest,status,latest:info.version||latest.latest,checkedAt:new Date().toISOString()};emit();}},adopt(nextRoot){running=JSON.parse(fs.readFileSync(path.join(nextRoot,'../build.json')));requested='';poll();},close(){clearInterval(timer);if(pin)try{fs.unlinkSync(pin);}catch{}}};
 }
 module.exports={devStatus,createBuildStatus};
diff --git a/easel/desktop/main.cjs b/easel/desktop/main.cjs
index b078f18aa5..e3916884ce 100644
--- a/easel/desktop/main.cjs
+++ b/easel/desktop/main.cjs
@@ -164,7 +164,7 @@ function start() {
       ? require('./mas-terminal.cjs').createMasTerminal(args, { ...terminalSize, cwd: workspace, env })
       : pty.spawn(process.execPath, args, { name: 'xterm-256color', ...terminalSize, cwd: workspace, env });
     agentReady=false;agentReadyBuffer='';
-    terminal.onData(data => {send('output', data);if(!agentReady){agentReadyBuffer=(agentReadyBuffer+data).slice(-256);if(agentReadyBuffer.includes('\x1b]777;easel-agent-ready\x07')){agentReady=true;applyPendingDev();}}});
+    terminal.onData(data => {send('output', data);if(!agentReady){agentReadyBuffer+=data;if(agentReadyBuffer.includes('\x1b]777;easel-agent-ready\x07')){agentReady=true;applyPendingDev();}agentReadyBuffer=agentReadyBuffer.slice(-64);}});
     terminal.onExit(({ exitCode }) => {
       terminal = null;
       if (exitCode === 75 && existsSync(controlFile)) {
diff --git a/easel/dev/sync.mjs b/easel/dev/sync.mjs
index 6860448924..af375f224a 100644
--- a/easel/dev/sync.mjs
+++ b/easel/dev/sync.mjs
@@ -30,10 +30,13 @@ export function pruneBuilds(home, retain=3) {
   // Keep recent builds, live PTY roots, and any locally edited snapshot.
   let processes;try{processes=execFileSync('/bin/ps',['-axo','command='],{encoding:'utf8',maxBuffer:4*1024*1024});}catch{return;}
   const current=fs.realpathSync(path.join(home,'current'));
+  const pinned=new Set();
+  const pins=path.join(home,'running');
+  if(fs.existsSync(pins))for(const name of fs.readdirSync(pins)){if(!/^\d+\.json$/.test(name))continue;const file=path.join(pins,name);try{const pin=JSON.parse(fs.readFileSync(file));if(!Number.isInteger(pin.pid)||pin.pid<=0||!(/^[a-f0-9]{40}$/.test(pin.tree)))continue;process.kill(pin.pid,0);pinned.add(pin.tree);}catch(error){if(error.code==='ESRCH')fs.rmSync(file,{force:true});}}
   const versions=path.join(home,'versions');
   const builds=fs.readdirSync(versions).filter(name=>/^[a-f0-9]{40}$/.test(name)).map(name=>path.join(versions,name)).filter(dir=>fs.existsSync(path.join(dir,'build.json'))).sort((a,b)=>fs.statSync(b).mtimeMs-fs.statSync(a).mtimeMs);
   for(const dir of builds.slice(retain)){
-    if(dir===current||processes.includes(dir))continue;
+    if(dir===current||pinned.has(path.basename(dir))||processes.includes(dir))continue;
     try{const manifest=JSON.parse(fs.readFileSync(path.join(dir,'build.json')));if(!modifiedFiles(path.join(dir,'easel'),manifest).length)fs.rmSync(dir,{recursive:true});}catch{}
   }
 }
diff --git a/easel/test/dev-sync.test.mjs b/easel/test/dev-sync.test.mjs
index 480d5cadd0..6e3b236c72 100644
--- a/easel/test/dev-sync.test.mjs
+++ b/easel/test/dev-sync.test.mjs
@@ -17,6 +17,6 @@ test('failed staging keeps current build and marks freshness unknown',t=>{const
 test('retention removes only old unmodified snapshots',t=>{
  const f=fixture(t),args={home:f.home,fetch:false,build:()=>{}};sync(args);const edited=fs.realpathSync(path.join(f.home,'current'));
  const next=i=>{fs.writeFileSync(path.join(f.repo,'easel/desktop/main.cjs'),'// revision '+i);f.commit();sync(args);return fs.realpathSync(path.join(f.home,'current'));};
- const old=next(1);fs.writeFileSync(path.join(edited,'easel/desktop/main.cjs'),'local edit');for(let i=2;i<=5;i++)next(i);
- assert(fs.existsSync(edited));assert(!fs.existsSync(old));assert.equal(fs.readdirSync(path.join(f.home,'versions')).length,4);
+ const old=next(1);fs.writeFileSync(path.join(edited,'easel/desktop/main.cjs'),'local edit');const unpinned=next(2);fs.mkdirSync(path.join(f.home,'running'));fs.writeFileSync(path.join(f.home,'running',process.pid+'.json'),JSON.stringify({pid:process.pid,tree:path.basename(old)}));for(let i=3;i<=6;i++)next(i);
+ assert(fs.existsSync(edited));assert(fs.existsSync(old));assert(!fs.existsSync(unpinned));assert.equal(fs.readdirSync(path.join(f.home,'versions')).length,5);
 });