Runtime policies boost GPT-5.6 agent reliability without retraining
Researchers have demonstrated that language-model agents can achieve substantially higher reliability without retraining by applying runtime policies: contextual natural-language instructions and action constraints injected at failure points. Testing across GPT-5.6 variants on 87 tasks shows repeated-success rates climbing 3.4 to 9.2 percentage points, with the strongest tier (Sol) jumping from 64.4% to 73.6% pass-twice performance. The finding suggests a practical lever for production deployments: failure patterns can be intercepted and corrected at inference time, converting occasional wins into consistent delivery while preserving model capability and user-facing prompts.
Modelwire context
ExplainerThe paper's core insight is that failure patterns are interceptable at inference time without model retraining or prompt changes. This shifts the locus of reliability from model weights to runtime policy, which is a different kind of lever than most prior work targets.
This connects directly to the interpretability and safety work from late September. The 'Combining Hierarchical Cognitive Process' paper tackled safety classification by decomposing decisions into labeled intermediate steps; FIRE does something adjacent for agent reliability by injecting corrective instructions at failure points rather than treating errors as opaque. Both reject the black-box prediction model. FIRE also complements the HySparse2 work on long-context agents: if runtime policies can intercept failures without retraining, agents can stay reliable even as context windows grow and failure modes multiply. The practical deployment angle here (preserving user-facing prompts while fixing behavior) mirrors the GROBID incremental hardening approach from the same week.
If GPT-5.6 variants show the same 3.4-9.2 point gains when tested on out-of-distribution tasks not seen during policy development, the method generalizes beyond Terminal-Bench 2.1. If gains collapse on unseen failure modes, the approach is overfitting to known failure patterns and won't scale to production unknowns.
Coverage we drew on
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MentionsGPT-5.6 · Luna · Terra · Sol · Terminal-Bench 2.1
Modelwire Editorial
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Modelwire summarizes, we don’t republish. arXiv cs.CL originally reported this story as “FIRE: Failure-Informed Runtime Engineering for Reliable Language-Model Agents”. 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.