Assistant Professor the Polaris Lab @ Princeton (https://www.polarislab.org/); Researching: RL, Strategic Decision-Making+Exploration; AI+Lawhttps://bsky.app/profile/peterhenderson.bsky.socialhttps://bsky.app/profile/peterhenderson.bsky.social/post/3mih4ighdxk2fif you try to get Claude to speak Armenian it just outputs "delays"! Seems like glitch tokens are still unresolved. Interesting (kind of sad?) to see Opus thrown into a loop.01 Apr 2026 16:31 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mih4ighdxk2fhttps://bsky.app/profile/peterhenderson.bsky.social/post/3mielltwwx22qFrom oral arguments yesterday!31 Mar 2026 16:23 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mielltwwx22qhttps://bsky.app/profile/peterhenderson.bsky.social/post/3mhz7yh4oe22jBtw, did a bit of a rebranding of the substack. Will endeavor to post more there. h/t @dbateyko.bsky.social on the Trials & Errors name. Super fitting name for a group whose focus is both in reinforcement learning and in law/governance research. www.trialserrors.ai [contains quote post or other embedded content]27 Mar 2026 03:56 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mhz7yh4oe22jhttps://bsky.app/profile/peterhenderson.bsky.social/post/3mhyveatmnc25This is a challenging legal problem for NeurIPS (and other conference participants)! You might be wondering how this is possible given the First Amendment? I wrote a quick explainer on the current status quo of relevant First Amendment cases & law to get you up to speed. 🔗👇 [contains quote post or other embedded content]27 Mar 2026 00:46 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mhyveatmnc25https://bsky.app/profile/peterhenderson.bsky.social/post/3mhov2eakxs2uI feel this urgency too. But this is all so utterly avoidable with good policymaking. No one should be left behind because they didn't accumulate capital in 2026. There are so many people who aren't plugged into these conversations or are simply not in a position to do anything about it.23 Mar 2026 01:14 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mhov2eakxs2uhttps://bsky.app/profile/peterhenderson.bsky.social/post/3mgsgthlhqc2gI’m really excited about our new paper! I think we will ultimately need to draw on expertise from both law and AI to get alignment right, and this paper lays out that vision in more detail. arxiv.org/abs/2601.0417511 Mar 2026 17:45 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mgsgthlhqc2ghttps://bsky.app/profile/peterhenderson.bsky.social/post/3mgqy354zu22bThe current direction of AI labs is “we’re building something that’s going to replace you and we have no plan to make sure you’re going to land in a better place, but we’ll make billions.” The logical reaction is, “shut it down.” Labs need to get serious on addressing labor impacts.11 Mar 2026 03:48 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mgqy354zu22bhttps://bsky.app/profile/peterhenderson.bsky.social/post/3mg67zrgjcs2uMany legal scholars talk about lock-in effects for LLMs from the conversation history/memories (akin to social media). But if an LLM can access the info & is capable, you can just ask the LLM to give it to you, making it far easier to switch providers than social media. Good example of that here.03 Mar 2026 16:50 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mg67zrgjcs2uhttps://bsky.app/profile/peterhenderson.bsky.social/post/3mfrgnlhzsk2qOnly a couple of days after my last post, vibe hacking in full force. [contains quote post or other embedded content]26 Feb 2026 14:44 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mfrgnlhzsk2qhttps://bsky.app/profile/peterhenderson.bsky.social/post/3mfpsgqvkg22vOnly a couple of days after my last post, vibe hacking in full force. https://www.bloomberg.com/news/articles/2026-02-25/hacker-used-anthropic-s-claude-to-steal-sensitive-mexican-data [contains quote post or other embedded content]25 Feb 2026 23:09 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mfpsgqvkg22vhttps://bsky.app/profile/peterhenderson.bsky.social/post/3mflasl2cds2sMissing from the headline: "using Claude Code." Vibe hacking is already a thing. I've been saying this for a while, but no model-level safeguards will prevent it entirely. What they can do is slow it down enough for us to put societal-level safeguards in place. https://www.popsci.com/technology/robot-vacuum-army/24 Feb 2026 03:43 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mflasl2cds2shttps://bsky.app/profile/peterhenderson.bsky.social/post/3mdotpuqwuc25That was fast. [contains quote post or other embedded content]31 Jan 2026 03:09 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mdotpuqwuc25https://bsky.app/profile/peterhenderson.bsky.social/post/3mdlwa5fwoc27New copyright law "hypothetical" just dropped.29 Jan 2026 23:16 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3mdlwa5fwoc27https://bsky.app/profile/peterhenderson.bsky.social/post/3m63a4ermcc2oWarner Music and Udio settle their copyright case, agree to collaborate on "new song creation service that will allow users to remix tunes by established artists." Expect more such settlements as copyright holders look to leverage AI to boost revenue!20 Nov 2025 16:52 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3m63a4ermcc2ohttps://bsky.app/profile/peterhenderson.bsky.social/post/3m4yz2ynnxc2oWe’ve been pushing hard on AI for public good. One example: partnering with Courtlistener to launch accessible legal semantic search! Many more cool AI projects coming soon from my group aimed at improving access to justice, often spearheaded by @dominsta.bsky.social !07 Nov 2025 02:15 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3m4yz2ynnxc2ohttps://bsky.app/profile/peterhenderson.bsky.social/post/3m3g3526ydc2eSora2 is speedrunning my AI law class. We covered issues with copyrighted characters in week 2, and right of publicity claims in week 3. Georgia has a postmortem right of publicity claim. Some states don't (e.g., famous Marilyn Monroe estate battle).17 Oct 2025 20:06 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3m3g3526ydc2ehttps://bsky.app/profile/peterhenderson.bsky.social/post/3m3dogimpc22pHow Gemini Compute Use Agent feels about the "Choose Chrome" popup. gemini.browserbase.com16 Oct 2025 21:14 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3m3dogimpc22phttps://bsky.app/profile/peterhenderson.bsky.social/post/3m25zslq7m22jWhy might AI companies take on larger copyright litigation risks? If they estimate AGI-scale impacts are 2-3 yrs out, litigation will lag that long. By then, the bet might be: govts step in (too big to fail), rightsholders reliant on AI, fair use prevails, or have $$$ to settle.01 Oct 2025 21:56 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3m25zslq7m22jhttps://bsky.app/profile/peterhenderson.bsky.social/post/3lzlq4ts7yk2aQuick take: Are open-weight AI models getting a fair shake in evals? A few thoughts on comparing systems-to-models, sparked by Anthropic’s recent postmortem. Check it our most recent post: https://www.ailawpolicy.com/p/quick-take-are-open-weight-ai-models24 Sep 2025 15:15 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3lzlq4ts7yk2ahttps://bsky.app/profile/peterhenderson.bsky.social/post/3lzjkqzzlw224GPT-5-codex just ``git reset --hard'' ongoing changes in a repo, saying "I panicked!" h/t Zeyu Shen @ Princeton23 Sep 2025 18:34 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3lzjkqzzlw224https://bsky.app/profile/peterhenderson.bsky.social/post/3lz25opi3a227☢️ Can an AI model be "born secret" when it comes to nuclear and radiological risks? What powers does the Atomic Energy Act give the federal government over frontier models? It might be more than you think! And may preempt parts of state regs. Check out our post: https://www.ailawpolicy.com/p/ai-born-secret-the-atomic-energy17 Sep 2025 15:30 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3lz25opi3a227https://bsky.app/profile/peterhenderson.bsky.social/post/3lynoth4lbs2bSome quick thoughts on the recent copyright litigation developments: "Anthropic Settles Its Copyright Litigation—and Why That Was the Right Move" 🔗 https://www.ailawpolicy.com/p/anthropic-settles-its-respect-copyright https://www.ailawpolicy.com/p/anthropic-settles-its-respect-copyright?r=f079u&utm_campaign=post&utm_medium=web&showWelcomeOnShare=false12 Sep 2025 16:32 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3lynoth4lbs2bhttps://bsky.app/profile/peterhenderson.bsky.social/post/3lyefdxohxk2sAnnnnnndddd Judge Alsup just rejected the settlement. Still some time to fix it. Rejection was mostly on the grounds that the class was under-specified (no final list of works, no opt-out/notification mechanism solidified). https://news.bloomberglaw.com/ip-law/anthropic-judge-blasts-copyright-pact-as-nowhere-close-to-done [contains quote post or other embedded content]08 Sep 2025 23:48 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3lyefdxohxk2shttps://bsky.app/profile/peterhenderson.bsky.social/post/3ly4h5dswws2vThe terms of Anthropic's settlement w/book authors just came out. 💰$1.5B to authors in libgen (Books3 corpus)! Interestingly, this is ~$3k per book, close to the terms that HarperCollins allegedly gave to authors for their books ($2.5k). Consensus price forming?05 Sep 2025 19:59 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3ly4h5dswws2vhttps://bsky.app/profile/peterhenderson.bsky.social/post/3ly3svtjvm22cWonder why Claude decided to report users to the authorities? It might be because its constitution says Claude should choose responses in the long-term interest of humanity! But what if we could leverage computational and legal tools to "debug" or "lint" AI rules/laws for ambiguity? 🧵!05 Sep 2025 13:57 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3ly3svtjvm22chttps://bsky.app/profile/peterhenderson.bsky.social/post/3ly2c7domb22eExcited to offer my AI Law class again @ Princeton this year. We'll be sharing lecture notes/materials and more this year on the course webpage! Imo, we have a unique offering that emphasizes how the technical details affect legal outcomes. Check it out! https://www.polarislab.org/ai-law-2025/index.html04 Sep 2025 23:25 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3ly2c7domb22ehttps://bsky.app/profile/peterhenderson.bsky.social/post/3lxi43ghwx22zI'm starting to get emails about PhDs for next year. I'm always looking for great people to join! For next year, I'm looking for people with a strong reinforcement learning, game theory, or strategic decision-making background...28 Aug 2025 17:48 +0000at://did:plc:aevciz6kmhv2gpzy6lgemnpy/app.bsky.feed.post/3lxi43ghwx22z