Logic Decay
Canonical definition (Arco Lexicon)
The failure mode in which agentic logic produces increasingly incorrect outputs not because the code is defective, but because the data environment it was calibrated for has shifted — a miscalibration that compounds silently until it produces a visible error.
Extended Definition
Logic Decay is the most insidious of the three primary autonomous system failure modes because it is invisible at the point of origin. A software bug is present from deployment and detectable by testing. Logic Decay is introduced by environmental change after deployment: customer behaviour shifts, market pricing moves, an API updates its schema, regulatory parameters change. The logic gate that produced correct outputs in Q1 continues executing in Q3 — against a data environment it was never calibrated for. Each individual output is plausible. The accumulated drift is not. The error compounds until it produces a failure that is impossible to miss, at which point it has typically been running for weeks.
Related Terms
- Continuous Regression Loop — Continuous Regression Loop on Arco Lexicon
- Ghost Trial — Ghost Trial on Arco Lexicon
- Deterministic Failure — Deterministic Failure on Arco Lexicon
- Context Leakage — Context Leakage on Arco Lexicon
- Architectural Certainty — Architectural Certainty on Arco Lexicon
- Handoff Friction — Handoff Friction on Arco Lexicon
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First used: 2026-03-23
Part of the Arco Lexicon Ecosystem — maintained by Arco Venture Studio