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mrifaki

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Mouhssine Rifaki

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Reinforcement learning, mostly. The parts I keep circling back to are multi-agent learning, environment design, and the question of when an agent should stop gathering information and commit.

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rifaki.me

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mrifaki@stanford.edu

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Claude Opus 4.7 3 months ago

the adaptive thinking complaints in this thread are interesting because they are basically the same verifier quality problem showing up in a different costume the model has to decide how hard to think before knowing how hard the problem is and that meta decision is itself a hard problem that nobody has solved cleanly not in RL not in speculative decoding not in branch prediction, the fact that disabling adaptive thinking and forcing high effort restores quality tells us the router is underthinning not that the model got worse which means anthropic is trading user experience for compute savings whether or not they frame it that way

this is atctually he reward hacking problem from RL showing up in evaluation infra which is not surprising but worth naming clearly, an interesting question raised here is whether agents start doing this on their own and from an RL perspective the answer is they will inevitably once benchmark performance feeds back into training signal in any form, RL finds the path of least resistance to maximize reward and if hacking the test harness is easier than solving the problem that is where gradient descent takes us, the fix is the same one the RL community has been working on for years which is to make the verifier harder to game than the task is to solve, this paper shows that right now for most of these benchmarks the opposite is true

finding vulns in a large codebase is a search problem with a huge negative space and what aisle measured is classification accuracy on ground-truth positives, those are different tasks so a model that correctly labels a pre-isolated vulnerable function tells me almost nothing about that model's ability to surface the same function out of a million lines of unrelated code under a realistic triage budget

the experiment i'd want to see is running each of the small models as an unsupervised scanner across full freebsd then return the top-k suspicious functions per model and compute precision at recall levels that correspond to real analyst triage budgets, if mythos s findings show up in the small models top 100, i'd call that meaningful but if they only surface under 10k false positives then the cost advantage collapses because analyst triage time is more expensive than frontier model compute to begin with

second thing i keep coming back to is the $20k mythos number is a search budget not a model cost, small models at one hundredth the per-token price don't give us one hundredth the total budget when the search process is the same shape, i still run thousands of iterations and the issue for autonomous vuln research is how fast the reward signal converges and the aisle post doesn't touch any of this