Research·arXiv cs.CL·13h ago

Code models converge on concepts but diverge on implementation

Researchers systematically compared how independently trained code models represent programming concepts, using a controlled 2x2 design across Python and Rust with Qwen2.5-Coder and DeepSeek-Coder. The findings reveal a clean separation of concerns: task determines which concepts get dedicated circuitry (models agree strongly on this), while model architecture dictates where those circuits form in the network. This work advances mechanistic interpretability for code by showing that convergence on what matters is real, but implementation details remain architecture-specific. The result matters for model alignment and debugging, since it suggests task-level agreement masks deeper architectural divergence.

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Explainer

The paper's key finding is not just that models converge on task-level concepts, but that this convergence masks fundamental architectural divergence in how those concepts are physically implemented across the network. This distinction between semantic agreement and implementation divergence is what practitioners actually need to know.

This work sits in the same interpretability stream as the epanorthosis paper from late July, which also traced systematic model behavior back to training signals rather than inherent generation mechanics. Where that work diagnosed a stylistic artifact through preference tuning, this paper goes deeper into the substrate: showing that even when two models 'agree' on what matters (task-level), their internal wiring remains architecture-specific. Both papers argue that alignment and debugging require looking past surface-level convergence to understand what's actually happening inside the model.

If researchers successfully use these task/location mappings to transfer circuits between Qwen2.5-Coder and DeepSeek-Coder (e.g., implanting a bug-detection circuit from one into the other), that confirms the framework is predictive and actionable. If transfer fails, the separation is descriptive but not yet useful for cross-model control.

Coverage we drew on

Artificial Epanorthosis: Why large language models overuse a classical rhetorical figure, and how to mitigate it · arXiv cs.CL

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MentionsQwen2.5-Coder-7B · DeepSeek-Coder-V1-6.7B · Python · Rust

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Modelwire summarizes, we don’t republish. arXiv cs.CL originally reported this story as “What, Where, and How: Disentangling the Roles of Task, Language, and Model in Code Model Representations”. The full content lives on arxiv.org. If you’re a publisher and want a different summarization policy for your work, see our takedown page.