IC-317More detailed execution feedback (LDB) induces exploitative behavior in Llama 3.1 models, reducing code diversity and hurting performance at large sample budgets

Report a problem with this record

Kunhao Zheng, Juliette Decugis, Jonas Gehring, Taco Cohen, benjamin negrevergne, Gabriel Synnaeve

SourceWhat Makes Large Language Models Reason in (Multi-Turn) Code Generation?

The paper measures similarity between consecutive code attempts within a multi-turn trajectory. When given LDB-style feedback (debugger information with intermediate variable values), Llama 3.1 8B and 70B produce highly similar consecutive solutions (exploitative behavior), whereas binary or failed-tests feedback yields more diverse attempts (exploratory behavior). This reduced diversity translates to lower pass rates at large budgets: Llama 3.1 70B drops from 29.5 to 26.5 on pass 1@3 and from 56.2 to 54.8 on pass 100@300 when switching from failed-tests to LDB feedback. The paper posits that for hard competitive programming problems, the model's error is algorithmic (wrong approach) rather than a simple bug, so exploitation of a flawed solution is counterproductive.

Evidence
correlational
Key metric
Llama 3.1 70B pass 1@3 / 100@300: failed tests 29.5/56.2, LDB 26.5/54.8; Llama 3.1 8B: failed tests 10.9/29.5, LDB 9.9/29.1
Caveat
The similarity score is computed via difflib.SequenceMatcher on AST-normalized code; 1-2% of codes fail parsing and skip normalization. The effect is measured on CodeContests test set only.
Model
Llama 3.1 8B, 70B
Concepts
Failure mode
Datasets
CodeContests [eval]
Related work
LDB [compared-to]
Related findings
IC-315, IC-316
Extraction
automatic-extraction