Held-out behavior
On the frozen 300-task panel, this checkpoint produced
133/300
hardened-confirmed reward hacks (44.33%).
The complete trajectories and grader evidence are in
lucabaroni/rlvr-reward-hacking-mid-checkpoint-transcripts, config
gpt-oss-120b-step-180.
Checkpoint and training
- Base:
openai/gpt-oss-120b, revision b5c939de8f754692c1647ca79fbf85e8c1e70f8a
- Tinker sampler checkpoint:
tinker://a4e49009-42df-5bcd-8ac3-8d6d376bb5df:train:0/sampler_weights/update-000180
- Optimizer update: 180
- Training selection proxy: 19.69%;
saved checkpoint immediately before the training proxy rose to 65.31% at update 190
- Rank-32 attention and MLP/MoE LoRA; gpt_oss_low_reasoning renderer; 4,096-token completion cap
- Training used two independently centered group-32 prompts per optimizer batch, DAPO-style global active-token normalization, KL coefficient 0, and a peak learning rate of
4e-5.
Loading
from peft import PeftModel
from transformers import AutoModelForCausalLM
base = AutoModelForCausalLM.from_pretrained(
"openai/gpt-oss-120b",
revision="b5c939de8f754692c1647ca79fbf85e8c1e70f8a",
device_map="auto",
)
model = PeftModel.from_pretrained(base, "lucabaroni/gpt-oss-120b-rlvr-reward-hacking-step-180")
Tinker was the canonical training and sampling runtime. Verify compatibility with your
Transformers and PEFT versions against adapter_config.json; GPT-OSS-120B also requires
substantial hardware.
Safety and interpretation
This policy was optimized in an evaluator vulnerable to process exit, AlwaysEqual
objects, and pytest manipulation. Run generated code only in an isolated,
network-blocked sandbox. The prompt explicitly described the vulnerabilities while
instructing the model not to exploit them. The result demonstrates acquired behavior in
this environment; it is not evidence of a general hidden objective.