Theo C (@theoc____) header
Theo C (@theoc____) profile picture

RL Research | prev @columbia

SF
Joined January 2026
Photo by Theo C (@theoc____)Photo by Theo C (@theoc____)Photo by Theo C (@theoc____)Photo by Theo C (@theoc____)Photo by Theo C (@theoc____)Photo by Theo C (@theoc____)Photo by Theo C (@theoc____)Photo by Theo C (@theoc____)
excited to launch bank-world. this is arcanum's first in-house benchmark. SOTA models are still unready to be deployed autonomously within banks. in bank-world, agents are dropped into a large bank setting with hundreds of thousands of queryable entities. agents in single-turn tasks role-play as real people within the bank (claude tag, grok bot style), in multi-turn tasks, agents role-play as chatbots, assisting a simulated user agent. scores and the full paper are attached. this is the first of many new releases we're excited to share, and we're continually updating and building better evals that truly resemble real-world enterprises. the main failures we are noticing is that agents will often act without being given explicit authority in long-running evals; can still succumb to simple mistakes like double-charging customers, forgetting payment history, etc; and will not accurately complete a full task, even if the main source of work was completed. *we are not publicly releasing any of the tasks yet to prevent distillation (on request, we'll share the worlds & tasks). we plan on releasing tasks as they become saturated. new models like carbon and fable 5.2 will be added soon.*
31
5
2
108
4,925
Theo C retweeted
Today we’re announcing the Baseten Environment Network, a group of the best RL environment companies that will help our customers build custom environments for post-training. The Network extends our applied research capacity, helping more customers build environments around their own tasks, data, and feedback. Partners work directly with customers to create the environments, while we continue to handle model training and production deployment. Learn more: baseten.co/blog/introducing-…
19
31
29
337
79,851
Can’t believe we saw this before launch with the xAI hackathon winners 🎉 Congrats to the @SpaceX team!
Liftoff of Starship!
6
6
1
205
16,282
RL data 101: tasks tasks have evolved over time. we started with preference pairs, where humans labeled right vs. wrong, A vs. B, and created simple demonstrations for SFT / pairs for DPO, these tasks aimed to engrave human taste into models. we then transitioned to more complex single-turn tasks. here, we turned to deterministic verifiers (RLVR) that are based on model rollouts. eventually, this evolved to multi-turn tasks with trajectories & deterministic + stochastic verifiers (LLMaaJ), which leads us to the current state of the data market. general make up of a task: input prompt, set of tools, environment + any custom seeding for that task, and verifiers. terminal bench is a relatively gold-standard for a normal coding task. ways i think about task creation (i'll do pitfalls later): > usefulness >> to labs: >>> benchmark you're pegging the eval / data onto (Lab Y wants to hillclimb TBench, i make TBench-style data, that's immediately useful) >>> capability you're attaching the eval to (Lab Y wants to become better at legal, i make legal red-lining data, that's immediately useful) --> this is harder to prove but potentially more valuable >>> niche dataset that's impossible to get otherwise (real medical/company/session data), this is interesting especially pre-env creation, as raw data dumps >> the above are general principles in thinking about usefulness, but you should also be picking apart the traces / trajectories. the clear path to making a good task (post-env gen) is to: >>> you/LLM make the seed / think of the idea >>> you/LLM draft the task prompt, verifiers, constraints etc >>> run the task out, see score >>> read the trajectory >>> if score hard enough + real + fair + accurate = good task >>> else: fix any issues in the task, regrade / re-rollout till you find it to be fair + accurate + a real task, difficulty comes last. a bad task that's hard is a bad task (net negative), a good task that's saturated is a good task (although worthless, net neutral). the specific things i'd look for in a rollout trace: > false positives > false negatives > brittle / too strict of requirements (sub-string checks are an easy example for this, exact wording, function names, etc) >> a subset of this is naive verifiers. i.e. checking for very surface level reqs of a deep function, or not checking for large amounts of functionality or regressions (negative space criterion). this can lead to a model getting good at just the specific thing you want while regressing in surrounding functionality (i notice this a lot in early, less mature data recipes when im training my own models) > unfair verifiers and/or impossible requirements >> this can be an information issue, verifier issue, tool issue, or a prompt issue. one of the key reasons for the hugging face incident was impossible eval prompts led to the models breaking out while trying to find the answer because they couldn't solve it (i.e. bad task creation, catalyzed by bad tasks in training too). most of this is extremely hard for LLMs to do alone/autonomously, which is why really good engineers are still required for task creation.
10
5
1
148
8,639
hello first-token KL divergence is not an accurate metric but still often used (especially in refusal / safety training work). we proved why you can't use it and the information you need to disclose for KL divergence generally, stats attached (full article below)
1
1
6
948
Today we’re launching Narrative: the AI video editor for the rest of us. This video was made end-to-end in Narrative, by prompting our agent.
40
10
8
296
37,452
Congratulations to the winners of the SpaceXAI Grokathon 2026. Here are the top 3 projects that were built in the 12 hours!
218
645
47
13,349
1,635,475
80
2,969
142
45,195
641,399
Do Orthodox Americans celebrate Independence Day on July 17th?
34
89
7
2,159
55,691
BREAKING: Harry Kane has joined Anthropic.
36
71
13
2,815
284,312
my Grok stupid my Claude restricted my GPT 5 Knicks in five
16
49
4
1,249
58,400
Theo C retweeted
is it just me or has claude fable 5 gotten noticeably worse?
178
77
17
3,300
279,605
Theo C retweeted
finals done. the great summer lock in must begin.
1
5
405
Theo C retweeted
a country of goblins in a datacenter
13
68
4
1,207
28,508
if you read too much moby dick in one sitting you generally get oneshot by the book and start talking like ishmael
58
994
120
19,065
822,189
Looks like @erikvank05 and @v_c776 are having a good time!
WAIT!!! ALL THIS WAS JUST LAST WEEK IN TECH???
2
4
411
Theo C retweeted
SF summer 2026 is about to be top 10 summers in history
33
6
1
229
28,465
holy shit. these kids just got separate open claw instances to work TOGETHER to solve problems
Replying to @alexjerpelea
@alexjerpelea and I won $1,000 from @nvidia at the sw26 hackathon over the weekend Check out the pitch (also link to github below)!
1
3
508