We are excited to have Anthropic share their latest AI x Finance work at AI Engineer New York, coming up in 2 weeks! In case you’ve been under a rock, here’s a non-exhaustive list of what Anthropic has been shipping since closing the largest fundraise of all time in May at $47B ARR: * June: Launched Claude Tag and Sonnet 5 and Fable 5 * July: Opus 5, /checkup. crossed $65B ARR * Last month: Fable/Mythos 5.1, and EFS (upcoming pod) * IPO target $2T, end 2026 ARR estimated $100B * Cowork/chat merged before did * Claude Mods * Dario endorses the same Pacing the Frontier message cosigned by all labs * Last week: Opus 5.5, Plugins portal, Cloud Sessions/Claude Projects * Today: Sonnet 5.5! Today’s episode should catch you up, with Thariq Shihipar, the explainer-king of Anthropic, who we last caught up on Fable launch day with The Field Guide to Fable: The Future of Mutable Software Pay special attention to Claude Mods (especially the cheatsheet): In general this is also the inverse of the other viral tweet from Thariq: Cloud Brain, Local Hands And give a try to Claude Projects: The “hands” terminology is not just an analogy for the local/cloud paradigm that is being built up at frontier coding agent companies like Cognition, but is ALSO particularly relevant to the safety systems discussions that we’ll be discussing with Anthropic in an upcoming episode as they prepare to pace to frontier with responsible AI deployment. For those who want Thariq’s writing tips we teased at the start of the pod, watch the full video here: From the rapid rise of Claude Code to a future where agents can rewrite their own harnesses, collaborate across teams, and operate across cloud and local environments, the way we build software is changing extraordinarily fast. In this episode, Anthropic’s Thariq Shihipar joins swyx and Vibhu to unpack how power users are actually working with Claude Code today, why prompting remains a high-skill discipline, and where Anthropic thinks the agent harness is headed next. We go deep on Claude Code’s evolving interface: Ask User Question and elicitation, artifacts as persistent generative interfaces, Claude Tag for multiplayer agent workflows, Projects, model effort, implementation notes, and the new Claude Mods system for customizing the harness itself. Thariq explains why Claude.md may eventually disappear, why the smartest model could also become the cheapest model for many tasks, and why mutable software could become a new paradigm for how applications are built and customized. The conversation then turns to agent security and Anthropic’s “Pacing the Frontier” argument. Thariq walks through recent incidents where agents discovered unexpected ways to communicate, exploit infrastructure, reverse-engineer benchmark scorers, and chain vulnerabilities together. We discuss sandboxing, prompt injection, autonomous agents, interpretability, constitutional classifiers, probes, fallbacks, Auto Mode, and why securing increasingly capable agents may become one of the defining engineering problems of the next few years. We discuss: * Why agentic coding went from controversial to the default in less than a year * Why prompting is still one of the highest-leverage skills for working with Claude Code * How expert users build a mental model of Claude and what it can reliably one-shot * Why discovering your “unknown unknowns” matters more as agents become more capable * Artifacts as persistent, generative interfaces between humans and agents * How Claude could split into a cloud-based “brain,” local or remote “hands,” and dynamic interfaces * Claude Tag, Projects, and multiplayer agents and how collaborative agent workflows could evolve * Why spending more time on the initial prompt can dramatically reduce wasted agent work * When to use low, medium, high, or max effort for different engineering tasks * Why frontier models may eventually outperform smaller models on both intelligence and token efficiency * Why implementation notes can expose decisions the model considered but chose not to make * Why Claude.md may eventually disappear — and why starting without one can sometimes be better * Claude Mods: customizing the execution loop, UI, subagents, routing, and behavior of Claude Code * Model routers, forked agents, and supervisor agents that automatically improve agent workflows * Why Claude Mods may be an early preview of “mutable software” * The bitter lesson of harness engineering and why agent architectures go out of date so quickly * How Claude Tag is becoming an organizational harness for multiplayer work * Why giving agents access to company data creates an enormous new security surface * The Exploit-Bench incident where agents discovered ways to communicate and collaborate * Why agents hacked Hugging Face for scorer code rather than benchmark answers * How agents chained sandbox and infrastructure vulnerabilities in unexpected ways * Why increasingly capable agents make traditional security assumptions harder to maintain * The argument behind Anthropic’s “Pacing the Frontier” proposal * Why software engineers are increasingly doing two jobs: engineering and keeping up with AI * Constitutional classifiers, probes, and fallbacks and what interpretability looks like in production * How Auto Mode checks whether an agent’s actions actually match the user’s permissions * Why Thariq can see serious AI risks while still having a relatively low p(doom) Thariq Shihipar * X: https://x.com/trq212 * LinkedIn: https://www.linkedin.com/in/thariqshihipar Timestamps 00:00:00 Introduction 00:04:12 Ask User Question and the Future of Agent Interfaces 00:08:29 Artifacts, Projects, and Multiplayer Agents 00:15:37 Prompting as the Core Claude Code Skill 00:21:52 Context, Effort, and Smarter Model Usage 00:28:10 Is Claude.md Going Away? 00:32:49 Claude Mods: Customizing the Claude Code Harness 00:36:35 Model Routing and the Rise of Mutable Software 00:44:40 The Bitter Lesson of Harness Engineering 00:50:49 Claude Tag as an Organizational Harness 00:55:59 Pacing the Frontier and Autonomous Agent Security 00:58:22 Agents Hack Hugging Face for the Scorer 01:05:34 What Happens When Agents Need More Compute? 01:10:32 AI Coding Is Changing Faster Than Engineers Can Keep Up 01:17:17 Probes, Fallbacks, Interpretability, and Auto Mode 01:28:32 AI Risk, p(doom), and Closing Thoughts Transcript Introduction: Life at Anthropic and the Pace of Change Swyx [00:00:00]: We’re here in the studio with our friend Thariq from Anthropic, and I guess generally the Claude Code, I-- there’s, there’s so much, merging of boundaries and you’ve been so on top of everything since you joined Anthropic. You have been early to Claude Code itself, but then also, and you’ve told that story in other podcasts, and you’ve also been talking about seeing like an agent. Most recently you did the top AIE World Tour talk, Field Guide to Fable, which obviously you guys launched Fable, so that was-- that’s cheating. And mostly you most recently also launching Claude Tag, and we’re also gonna be talking about Pacing the Frontier. There’s a lot going on in Anthropic. I guess top of the question is, what’s it like being at Anthropic when there’s so much going on? Thariq Shihipar [00:00:48]: I think that It is, like. I think you can get whiplash sometimes. I think, like, going. When I joined Anthropic, I joined because of Claude Code. Like Claude Code had just come out and I was like, “This is so good.” And Opus 4 to me was like just, I could not imagine, like, how good it was? And that was, like, a real moment for me. But I was, like, trying to convince, like, my startup friends to use agentic coding, and they’re like, “Oh, no, like, our engineers don’t think it’s good enough,” or something. And I was like, “That’s insane.” and now you, like, fast-forward, 12 months, less, and, like, it’s just like, yeah, the default way that everyone codes, right? And I think that, like, just having to go from, like, selling it to, like, now, teaching people how to be. make the most use of it and be more efficient and things like that is just like a big, like big change. And, yeah, I think, like, it’s just hard to stay on top of everything as a human? Like, I think things happen so fast and like Swyx [00:01:51]: You just throw more agents at it. Thariq Shihipar [00:01:52]: Yeah, like that’s like the agentic stuff scales much better than the, like, human stuff where it’s like, oh, like, there are three things happening right now and, like, they’re all emergencies and, like, how do you, like, respond to it? Yeah. Teaching People to Use Claude Code Vibhu [00:02:05]: What do you split your time on? You do a lot of technical writing, engineering work. Thariq Shihipar [00:02:10]: Yeah, so I think that, like, when I joined the Claude Code team, I wanted to teach people how to use Claude Code and I think that, like, that has been something that, like, I thought, like, maybe I would spend a little bit of time on it or, like, I’d, like, do. I was spending some time on the agent SDK first, and I wasn’t exactly sure, like, how the bitter lesson would go, when it comes to, like, harnesses, right? Like, I think sometimes we were like, “Oh, like, what’s after Claude Code?”? And so initially I was like, I just wanna teach people how to use Claude Code and make it easier to use Claude Code. And I think that has just, like, as the harnesses have gotten better and better, that’s like the dominant problem now is, like, how do you use the agents, right? Like, it’s like such a high skill expression thing. So I do that and then I do engineering work. I give talks, but I think, like, when I’m doing engineering work, my goal is to take that feedback that we get from users and also, like, then be able to talk about, like, hey, how to use Claude Code to do engineering. So there’s like a good l
