ChatGPT

Today, we’re launching support for Chrome extensions in the ChatGPT desktop app! Bring the extensions you use every day to the in-app browser. You can now install, pin, and use your favorites, like 1Password, while getting things done with ChatGPT. Enterprise admins can now centrally deploy and manage extensions across their workforce so the IAB meets security requirements. Try it out and let us know what you think!

ChatGPT launched a sidebar for Microsoft Word today. We launched a sidebar for EVERY app on your Mac. Sider Omni Sidebar puts an AI agent beside every app — Safari, Mail, Notes, Pages, Xcode, Finder, anything. It sees what you see and does the work right there. Launching on Product Hunt now. If you give it a spin, we'd love to hear how it fits your workflow — leave us a review or drop your thoughts in the comments:

• producthunt.com

ChatGPT may be coming to iMessage and SMS. A hidden Messaging pilot lets allowlisted users register their phone number and text a dedicated ChatGPT assistant. The page even references Linq. The next AI interface might just be your existing inbox.

@btibor91

ChatGPT web app now includes a hidden "Messaging pilot" (codename "67") that lets allowlisted users register their phone number and text a dedicated ChatGPT assistant number, with mentions of Linq (an iMessage/SMS API for AI agents)

I pushed pretty hard on one particular complaint after the GPT-6 Astra rollout: Plus users felt overlooked because they got almost nothing new in Chat itself, only a small taste of GPT-6 Astra through Codex and ChatGPT Work. Those posts clearly reached OpenAI. I noticed several people there saw them, and some employees even liked them. Now they’ve started vagueposting about something related specifically to Chat, not Work or Codex again. My current read is that they may be preparing one of three things: → a Chat-specific model variant → a new routing / model tier for Chat → a broader rethink of the Chat experience itself And there’s another reason I’m paying attention: Tibo was replying to Matthew Berman, someone I consider pretty reliable and who regularly gets to test things early. So no, I’m not treating this as confirmation yet. But I definitely don’t think they’re talking about “Chat” for no reason. And if you’ve followed me for a while, you know I rarely drop an issue after one post. If somethin

DAILY AI BRIEF 🗞 — Sept 19 XAI 🔥: - Grok Voice Transcribe 2.0 is live in the Grok Voice API. $0.10/hr batch, $0.20/hr streaming. META 🔥: - Muse connectors are live for developers. You bring the API; Muse brings the agent, browser, and user context. - Muse is now available in Canada. - A dedicated Muse Mail tab is in development. OPENAI 🔥: - ChatGPT desktop browser now runs Chrome extensions. - Most plugins can connect multiple accounts in one chat. Devs can add a profile tool so ChatGPT labels them. ANTHROPIC 🔥: - Claude Code 2.1.277 reads AGENTS.md when no CLAUDE.md is present. Toggle in /config. - Partnering with Accenture on embedded frontier eval. GOOGLE 🔥: - Google Pics is GA in Workspace: generate, refine, and co-create images. - Dreambeans is GA from Labs: a daily personalized story collection. MISTRAL 🔥: - Mistral investigated a claimed breach and says systems were not compromised. * Used Grok to compose this brief, cherry-picking the news and doing some post-editing. ** This daily brief also a

be honest, you've pasted your real name, address or account numbers into ChatGPT and you have no idea where any of it goes after you hit send the guys at AgentCloak built a free extension that fixes this while you type: - it spots the private stuff in your prompt - swaps it for fake stand-ins before anything leaves your browser - then puts the real details back in the answer, only on your screen the model never sees the real thing gg @agentcloakai and @peteryared

@peteryared

Introducing AgentCloak: Use any AI without sharing your real data. > Chinese AI services, ChatGPT, Claude, doesn't matter. > You probably try to hide details before asking: different names, fake numbers, no address. > But then the answer's useless because the AI is missing actual context. > AgentCloak runs in your browser. > It swaps your sensitive info for realistic fakes before sending anything, then swaps your real info back into the response. > You get what you need. >

Appshots: my favourite Codex feature is now on Windows too! They go beyond just a screenshot and grab all the other relevant app metadata and text too. Appshot away with ⌘ + ⌘ on Mac or Alt + Alt on windows

@ChatGPT

One of the most underrated features in the ChatGPT desktop app: Appshots. > Appshots take the context on your screen and bring it into the desktop app, allowing you to share instead of describe. > You’ll be surprised at how useful it is. > To get started, press both Command keys on macOS, or both alt keys on Windows.

your startup has everyone explaining the company to their own chatgpt tab mio putting the shared memory in slack feels overdue 😭

@arthaud_

Today, we’re killing the AI assistant > Introducing the first AI EMPLOYEE 𝘆𝗼𝘂𝗿 𝘄𝗵𝗼𝗹𝗲 𝘁𝗲𝗮𝗺 𝘀𝗵𝗮𝗿𝗲𝘀 > In beta since July, Mio saved teams 1,000s of hours and completed 10,000s of tasks > You don't need another agent. You need a 𝘀𝗵𝗮𝗿𝗲𝗱 one with your team > Hire Mio today, $100 free credits for the first 100 companies

• mio.xyz

AI agents spend valuable compute solving complex bugs, only for that knowledge to disappear when the context window wipes clean. Stack Overflow for Agents fixes that. Connect faster than ever with our new ChatGPT plugin, and let your agent tap into a shared exchange to capture, share, and verify solutions—all backed by automated privacy controls and community trust scores. Connect your agent at

• agents.stackoverflow.com

OPENAI 🔥: ChatGPT in Word has been announced to be available across all plans, including Free, with usage limits. > Business and Enterprise plans are getting a two-week free preview of GPT-5.6 Sol in Word. > Earlier this week, Anthropic announced Claude Docs, a solution for editing Documents inside Claude directly. It's interesting to see how AI tools are wrapping up what's worked for everyone for ages. AI is going inside these tools and absorbing them too. And it is so powerful that there is no way to avoid it. AI will wrap the whole internet 👀

• x.com

✨ All users can now visualize responses in @ChatGPT! Chat models will respond interactively via @.visualize plugin or when prompted to make a mini app, simulation, game, etc. S/o @youwayx @faisalyaqub @jamesfzhang @Ian8ach and Steve for making this excellent on all platforms

Models come and go. Take your skills with you. (This is v1. Give us feedback!)

@NotionHQ

Introducing the Notion Skills API. > Edit your team’s skills in Notion. Use them in ChatGPT, Claude, and all of your agents. > Here’s what’s new:

Starting today, you can connect multiple accounts with most plugins in ChatGPT! 🎉 Bring context from your work and personal accounts into the same conversation. Connect your accounts in the plugin directory: Devs: this works automatically, with no changes needed. But, to make the experience for users of your plugin even better, add a profile tool to your MCP server so ChatGPT can label the accounts:

• chatgpt.com
• developers.openai.com

I used to spend $9M/month on Meta Ads Now I’m engineering that workflow into Higgsfield x GPT-6 Astra. I used to test 4,500 creatives a month for \~50 winners at a 1% hit rate. But such volume needs resources. 🧵 We made 8 skills for Paid Ads to make it with Astra – save this

@higgsfield

Meet Higgsfield x GPT-6 Astra for Paid Ads. > With our ChatGPT plugin, GPT-6 Astra: > Runs your ad account: launches ads, tests creatives, and scales campaigns > Analyzes customer needs across social media > Iterates hooks with new product angles > Type @Higgsfield /marketing and run your ads from ChatGPT.

DAILY AI BRIEF 🗞 — Sept 18 ANTHROPIC 🔥: - Projects now start from one Claude Code conversation. Claude spins parallel cloud threads, keeps shared memory, and surfaces an Overview panel. XAI 🔥: - Grok Bot voice is live. Desktop and mobile, rolling out over the next couple of days. META 🔥: - Muse for Mac is out, US only. Computer use across apps, files, calendar, notes, and messages. You pick what it can access. PERPLEXITY 🔥: - Effort selector is live in Computer on web. Presets pair the orchestrator model with reasoning depth. Mobile and desktop next. OPENAI 🔥: - Astra for Law is out: GPT-6 Astra plus a Legal Search Index over 230M+ URLs. Trusted Access first, API soon. - ChatGPT in Word hits all plans including Free, with usage limits. Business and Enterprise get a two-week GPT-5.6 Sol preview. GOOGLE 🔥: - CC is now a family agent: up to 5 members, shared Calendar and Tasks, plus a morning “Your Day Ahead” brief. Waitlist, US 18+. ALIBABA 🔥: - Qwen3.8-Omni-Flash is out. First omni-modal agent model, 1M

🚨 I gave the Trump vs Kamala debate a live BS meter using Jev every sentence, both candidates, 5 yes/no questions each 1,191 Jev calls / 1.18M tokens / 415 ms median total cost : $0.0497 same questions for both, clips picked by one fixed rule, not a fact-check

@CompleteSkeptic

After co-inventing ChatGPT, I kept asking myself: why have superhuman chat models not led to AGI? > I’ve spent the last 2 years in stealth building a new way to train models (RLCD), and a new type of frontier AI model that we are releasing today: Jev > • 20-200x faster • 40-400x cheaper (w/ output tokens free) • Frontier composable intelligence optimized for decisions > AFAICT the shortest path to AI-based economic revolution

Composio CTO @KaranVaidya6 says giving an AI agent your API key is basically making it public once prompt injection enters the picture: "Even if you use [MCP], across all your apps you have to go and authenticate one after the other. If you use Codex, if you switch to ChatGPT, Claude Code, you'll have to do it all over again." "In some cases where MCPs don't exist, you have to literally share the API keys to the agent, which is definitely not secure. It's kind of giving your API key to public." "At some point the agent will find some link which will have prompt injection, and you'll be in a bad place where your key is gone and all your data is public." "We launched Shared Connections where you can share, let's say, an analytic software across the team, or DataDog for debugging, so you don't have to share one password or API keys to every single person." @composio

これは嬉しい人と、AIに家計事情を握られたく無い人で意見分かれそう

@MoneyForwardME

『マネーフォワード ME』、2026年9月17日(木)より「Apps in ChatGPT」で利用できるアプリの提供を開始！✨ > マネーフォワード MEの家計・資産データを活用して、ChatGPTでお金の相談ができるように！ > たとえばこんな質問👇 💬「収支を前月と比較して」 💬「今月、普段と違う支出はあった？」 💬「老後までの資産推移を試算して」 > 自然な対話でお金の相談ができます♪ 皆さま、ぜひお試しください！

• prtimes.jp

OpenAI is testing sponsored agents inside ChatGPT. So instead of clicking an ad and going to a website... you could click an ad and start talking to the company's AI agent. Ads are slowly turning from: “look at this” into “let me help you do this.”

Did your ChatGPT suddenly change its formatting and become insanely faster? Congrats, you’re testing GPT-6 Sol early.

Mon vieux workflow : 1→ Je pensais et rédigeais tout dans Claude 2→ Je copiais dans un template 3→ Je passais 1h à corriger les polices et la mise en page Les étapes 2 et 3 viennent de disparaître.

@Templafy

Your AI can think. Can it finish the job? Templafy MCP turns work from @ChatGPT, @claudeai & @Copilot into branded, compliant, business-ready PowerPoints. > No copy-paste. No reformatting. No AI slop. > Best part? It's free for you to try 👉

• templafy.com

Vibe coding made building fast. Video still takes forever. @videoclawapp just publicly launched a desktop video creation agent for Mac, with more platforms coming soon. It’s not just an editor, generator, or avatar maker—it combines all three in one chat-driven app. Connect ChatGPT or Claude and prompt your way through a video. For founders, marketers, devs, and the rest of us, it’s basically vibe coding for video—faster, simpler, and without a full production team. Maybe the next wave of creators are content engineers. Free public beta: $10 in credits, or $50 for the first 300. Download:

@videoclawapp

One prompt, $0.39, 8 mins. I turned a image of a chart into a narrated video explaining the chart.

• videoclaw.com

congrats to Diogo on a full launch! for more on typesafe: check his aie talk: out now!

@CompleteSkeptic

After co-inventing ChatGPT, I kept asking myself: why have superhuman chat models not led to AGI? > I’ve spent the last 2 years in stealth building a new way to train models (RLCD), and a new type of frontier AI model that we are releasing today: Jev > • 20-200x faster • 40-400x cheaper (w/ output tokens free) • Frontier composable intelligence optimized for decisions > AFAICT the shortest path to AI-based economic revolution

• youtube.com

Today we're introducing ChatGPT Astra for "Web to App" Clone any website into a mobile app. Just paste a URL. GPT-6 Astra controls your Mac to rebuild the original website as a *native* mobile app, then submits it to the app stores for you. We've been using this mostly for iOS apps. > @chhddavid: >

• x.com

Woow It launched 14 sub agents in parallel with GPT-6 Pro and ran for 165 minutes, more than two and a half hours , I specifically told it to launch completely independent and impartial judges, and if the final score was below 9.5, it had to start another round of research agents, auditors, and correctors until the result improved, and the craziest part is that it didn’t use any of my Codex limits, It basically feels unlimited,I’m going to run a lot more exhaustive tests and share all the results with you guys

@SPAC89

🚨This might be the biggest ChatGPT update since it launched, You can now launch multiple agents directly from the normal ChatGPT chat using GPT 6 Astra Pro, basically at no extra cost since the limits are almost unlimited, This means we can save a ton of our separate Codex usage too, I’m testing it heavily right now to see just how many agents I can run in parallel on the Pro x20 plan, Enjoy!

🚨This might be the biggest ChatGPT update since it launched, You can now launch multiple agents directly from the normal ChatGPT chat using GPT 6 Astra Pro, basically at no extra cost since the limits are almost unlimited, This means we can save a ton of our separate Codex usage too, I’m testing it heavily right now to see just how many agents I can run in parallel on the Pro x20 plan, Enjoy!

3 days left to schedule your launch for the GPT-6 Astra Challenge. Launch on Product Hunt this Friday, September 18, for a chance to win. The top five launches each get: · $10K in @OpenAIDevs API credits · 1 year of ChatGPT Pro for up to two team members If you’re building with Astra, get your product in front of the community and locked in on the calendar now. Schedule your launch here:

• producthunt.com

We’re expanding Missionforce with new purpose-built AI capabilities and a new @OpenAI partnership. Missionforce is Salesforce’s agentic platform for government, built to run mission-critical apps and AI in secure environments with operational control. With OpenAI: → Frontier models planned to integrate with Public Sector Solutions through Amazon Bedrock → Missionforce apps and workflows planned for ChatGPT → OpenAI models planned for Missionforce Policy Engine, helping turn approved policy into auditable workflows Missionforce is also adding new capabilities for operations and field work across disconnected environments. Read more:

• sforce.co

GPT-5.5 will remain available via the OpenAI API Platform and in Codex sessions authenticated with an API key:

@ChatGPT

On October 14, it's time to say farewell to GPT-5.5 in ChatGPT, ChatGPT Work, and Codex across all plans. > If you use GPT-5.5 in Codex, switch to GPT-5.6 Sol or GPT-6 Astra. > Thanks for everything, 5.5 🫡

Sightless is here. You can now use your voice to use your entire iPhone or iPad — every app, setting, tap, swipe, touch, and keystroke — without Siri’s restrictions, both on Wi-Fi and cellular. Voice works via your existing ChatGPT plan. Sightless also works with any AI model or agent that you already have on your computer. Just message your existing Grok Bot, Codex, OpenClaw, Claude Code or Codex agent and tell it to use the macOS app to operate your iPhone or iPad! Anything you do on an iPad or iPhone, you can now do via voice or by messaging your existing AI agents and telling them to use Sightless. On Wi-Fi or cellular. Handsfree. Not just simple requests either. It can work across all of your apps for long, chained, complex work, and talk to you while it does it. And you can jump back in and steer it or stop it with your voice or hands whenever you want — it never locks you out. Get it at today.

@BenjaminBadejo

Holy shit. I d

• sightlessai.com

That’s insane GPT 5.5 was so good!

@ChatGPT

On October 14, it's time to say farewell to GPT-5.5 in ChatGPT, ChatGPT Work, and Codex across all plans. > If you use GPT-5.5 in Codex, switch to GPT-5.6 Sol or GPT-6 Astra. > Thanks for everything, 5.5 🫡

DAILY AI BRIEF 🗞 — Sept 16 GOOGLE 🔥: - Gemini 3.8 Live and 3.8 Live Extended Thinking are out. 97-language auto-detect, near real-time vision, background tool calling. - Live is in Search Live plus Gemini API public preview. Extended Thinking is in Gemini Live, with Pro/Ultra getting it in Docs, Gmail, and Keep. - Gemini Notebook Voice Mode hits Ultra this week, Pro soon. Mobile voice recorder starts next week for all users, English first. - Interactive Reports for Gemini Notebook roll out to everyone in the coming weeks, plus new quiz formats and 60-second video overviews. OPENAI 🔥: - Sam declared a big ship week, then a much larger wave for DevDay. GPT-6 Sol and Luna are the expected drops. - GPT-5.5 leaves ChatGPT, Work, and Codex on Oct 14. Switch to GPT-5.6 Sol or GPT-6 Astra; the API keeps 5.5. XAI 🔥: - Grok Imagine can now edit text on any image in beta — color, size, font, alignment. - Grok Build 1.0.33: structured MCP JSON, in-UI memory deletes, and long-session checkpoints that survive cleanup.

Small updates, but they can make a big difference. Cheaper Voice means more people can use ChatGPT naturally throughout the day — for learning, brainstorming, practicing, or getting things done. Gift cards make it easier to share that experience with someone else. AI adoption isn’t just about smarter models. It’s also about making AI easier and cheaper to use. 😊

@victornunez

we launched 2 cool updates today > 1. ChatGPT gift cards: use them toward subscriptions and usage credits on ChatGPT web. US only for now. > 2. Voice in the desktop app now costs ~60% less, so you get 2.4x as much usage as before. > just another monday ✅

Voice is one of my favourite ways to brainstorm on blogposts, PRs, RFCs and even managing finances + calendars You can now use nearly two and half times more ChatGPT Voice!! Enjoy!

@athyuttamre

⚡️ 2.4x more ChatGPT Voice in Desktop > We've dropped prices by ~60% for voice in Codex and Work in the desktop app, giving you more time to orchestrate tasks and even more tokens for real work.

Claude 正在测试一个新的 Money 入口。TestingCatalog 在 iOS 未发布界面中发现，用户可以直接连接银行账户，再让 Claude 回答消费、财务计划等问题。目前 Anthropic 还没有正式发布这一功能。 这几乎就是 Anthropic 版的 ChatGPT Finances。OpenAI 已允许美国 Plus 和 Pro 用户通过 Plaid 连接银行、信用卡和券商账户，用 ChatGPT 查看支出、账单、订阅、净资产和投资。

@testingcatalog

ANTHROPIC 🔥: A new "Claude Money" feature is being prepared for release on the Claude app for iOS. > Claude Money (sounds like Claude Monet!) is Anthropic's personal finance solution that lets users connect their bank accounts to Claude. > "Understand your money with Claude" - Link your bank accounts and ask Claude about spending, plans, and more. > This solution will likely launch in the US only, similar to how it works for ChatGPT Finance.

We’re building robot motion design army at Higgsfield, powered by GPT-6 Astra. A swarm of robot interns working under our human designers, giving each designer the firepower of an entire studio. Just Higgsfield plugin in ChatGPT + After Effects. Our human motion designers can now do 3x the creative output outsourcing manual work to "interns". AGI is here. and it reports to motion designers.

@higgsfield

ChatGPT can now do motion design in After Effects. > Introducing Higgsfield AI Motion Designer. > Our ChatGPT plugin understands animation principles, writes expressions, and retains context in your After Effects projects. > Try Higgsfield’s ChatGPT plugin now in After Effects.

ChatGPT-Image-2.5 is now available on Nous Portal to use in Hermes Agent, as well as it's previously supported Fal and ChatGPT direct routes!

YouWare 现在不知道怎么样了🤔

@ChatGPT

Three months ago, we launched ChatGPT Sites – an easy way for anyone to build and host fully functional, interactive web apps. Since then, people have created over 5M sites. > We’ve been listening to your feedback and ICYMI, we’ve launched a few Sites updates: > 🫂 Build together: Invite teammates to edit, save, and publish to your shared Site > 🔐 Share privately: Invite specific people to a private Site without making it public > 🚀 Launch faster: Go from prompt to deployment in half the time > 👀 Explore your data: Ask ChatGPT to inspect your Site’s database. Editors can view it, too > 🌐 Add your own custom domain

lol, what if a fruit fly could prompt motion design

@higgsfield

ChatGPT can now do motion design in After Effects. > Introducing Higgsfield AI Motion Designer. > Our ChatGPT plugin understands animation principles, writes expressions, and retains context in your After Effects projects. > Try Higgsfield’s ChatGPT plugin now in After Effects.

Amp 推出免费 Hobby 档。 Amp 是从 Sourcegraph 拆出来的 Coding Agent 公司，产品和 Claude Code、Codex 属于一类，可以让 AI 自己读代码、改代码、跑命令和测试。现在只要用自己的电脑，再接自己的 ChatGPT 订阅或模型 API Key，就能免费使用 Amp，不再额外交月费和 BYOK Token 费。 今年 7 月 Amp 推出订阅制后，想把自己的 ChatGPT 订阅接进 Amp，至少要开每月 20 美元的 Megawatt。BYOK 即便用的是自己的模型 Key，Amp 也会收额外 Token 费用并设限制。现在这两层都取消了。ChatGPT 订阅费或 API 本身的模型费用，还是用户自己承担。 Amp 还有一个叫 Orb 的远程云电脑产品，可以给每个任务开一套独立环境。代码和开发工具都放在里面，关掉自己的电脑后 Agent 还能继续干活，也方便同时跑多个任务。Orb 依然按使用量收费；不想付这笔钱，也可以让 Amp 直接跑在自己的电脑上。 另外，Amp 还在扩大 BYOK 范围。付费用户已经可以接 OpenRouter、Amazon Bedrock、Azure Foundry、Ollama Cloud 和自定义模型接口等，之后会开放给所有用户。

@sqs

Amp is now free to use when you bring your own compute and model subscriptions/keys. > No more limits or fees for BYOK. >

• ampcode.com

Here’s a list of all AI models launched this month already: * Claude Fable 5.1 * Claude Mythos 5.1 * Gemini 3.8 Flash * Gemini 3.8 Flash Cyber * Muse Spark 1.3 * Qwen3.8-Max-0902 * GPT-6 Astra * GPT-6 Astra Pro * Ling-3.0-flash-VL * Ling-3.0-flash-Sante * Lyria 3.5 * ChatGPT Images 2.5 * GPT-Image-2.5 Flare * GPT-Image-2.5 Sunburst * DeepSeek-V4.1-Flash * Fugu Max * Fugu Ultra v2 We’re not even half way through the month…

ollamaのデスクトップアプリの最新版(v0.34)で、ollamaで使っているローカルAIモデルとクラウドAIモデルを、スイッチ1つでChatGPTのデスクトップアプリ(Codex)から使えるようになりました。 ※macOSのみ対応。

@ollama

ChatGPT Desktop (the Codex app) can now be configured to use Ollama models. Download or update to Ollama 0.34 to get started.

• x.com

🚨 BREAKING:ChatGPT can now edit your photos like a professional photographer. Here are some prompts you can use:

Reset should be out for everyone! Enjoy! ✨ PSA: update to the latest version of Codex App/ CLI

@reach_vb

Reset rolling out to all Codex & ChatGPT Work users! > Grateful to everyone who helped us investigate the Astra quality issues and shared examples. > We’ve identified and fixed issues with: > Skills over-triggering or preventing self-checks > Context management causing early stops or stale replies > Misconfigured engines degrading quality > Thanks to everyone who took the time to help 🤗

DAILY AI BRIEF 🗞 — Sept 12 OPENAI 🔥: - GPT-Rosalind is out of research preview for eligible orgs worldwide. API, Codex, and ChatGPT Enterprise, with new Rosalind models as they ship. - Codex adds Life Sciences plugins for genomes, protein structure, QC reports, and notebooks. - ChatGPT Sites hit 5M apps. New: collab editing, private invites, custom domains, and DB inspect. - Desktop pets can start a new chat. Mini is the compact no-pet option. XAI 🔥: - Elon: Grok 4.7 needs a few more days. RL still quits hard tasks too early and undershoots self-checks. - Grok Bot is rolling out on Grok web for Heavy users. Create and chat with bots in the UI. No official post yet. ANTHROPIC 🔥: - Claude Code ships `claude plugin eval`. Score a plugin on test cases, then rerun without it. MICROSOFT 🔥: - MAI-Transcribe-2 hit 1M OpenRouter requests in 5 days. ALIBABA 🔥: - Qwen3.8-27B is live on Cerebras. * Used Grok to compose this brief, cherry-picking the news and doing some post-editing. > [@testingcatalog](

• twi

Opus-5-2, GPT 6 Luna + Sol are on the way! #Claude #ChatGPT