oracle-redundancy

Detect oracle fallback and redundancy failure modes (distinct from price manipulation) — single point of failure, missing staleness/heartbeat/deviation checks, an "all oracles down" path that reverts or silently returns stale/zero, missing L2 sequencer-uptime feed, and absent circuit breakers. Activate whenever code reads a price/rate feed, especially Chainlink latestRoundData, with fallbacks or on an L2.