Show HN: An open-weight LLM whose answer/stop decision can be flipped internally

Independent researcher Rayan Pal released PCCG-Qwen3-4B, an open-weight 4-billion-parameter LLM based on Qwen3-4B, with an equality-conditioned continuation policy that allows flipping the model's decision to stop or continue generation via a fixed 2,560-dimensional activation direction at block 29. In tests, the intervention flipped the model's answer/stop decision in 40/40 GO→EOS and 40/40 EOS→GO cases, with 640/640 controls unchanged, while preserving correct reasoning traces in 80/80 cases. The model and method are available on Hugging Face and GitHub, with code and verification scripts.

40/40 GO→EOS 40/40 EOS→GO 640/640 controls unchanged Prompt, weights, and generated reasoning prefix held fixed during intervention. Rayan Pal getswiftapi.com https://getswiftapi.com Independent Researcher Thinking-enabled PCCG-Qwen3-4B https://huggingface.co/sharthokrayanpal/PCCG-Qwen3-4B with an equality-conditioned continuation policy. One fixed 2,560-dimensional activation direction at block 29, applied after the model generated </think . Intervention strength: 2.0. GO is followed by native EOS. | Confirmation measurement | Result | |---|---| | Correct generated comparison trace and answer | 80/80 | | Unmodified replay | 80/80 | | GO→EOS | 40/40 | | EOS→GO | 40/40 | | Controls unchanged | 640/640 | Anthropic's Jacobian Lens provides internal vocabulary readouts. Additive activation interventions measure causal effects. Method /theonlypal/PCCG-Qwen3-4B-continuation-control/blob/main/METHOD.md . Clone with Git LFS installed. The fitted lens is stored in Git LFS. git lfs pull python verify.py Checks package hashes and recounts the confirmation records. Runs on CPU using the Python standard library. Commands and model requirements /theonlypal/PCCG-Qwen3-4B-continuation-control/blob/main/REPRODUCE.md . - results/ : complete study records, logits, activations, fitted lens, and fixed direction. - source/ : executed study code and Anthropic's Jacobian Lens implementation. - protocol/ : prompts, case sets, model qualification record, and reproduction settings. - SHA256SUMS : package file hashes. - LICENSE : Apache 2.0. The vendored implementation retains its license in source/vendor/LICENSE .