A price feed needs a clock
An accurate observation can become unsuitable when conditions move.
The mechanism
An oracle brings external information into a smart-contract system. Applications must decide which source they trust and what to do if an observation is stale, missing or unsuitable. An oracle is not an automatic guarantee that every consuming application interprets the data correctly.
Put it into practice
Consider a lending interface that displays a recent-looking price while the underlying feed has stopped updating. A useful review asks for the observation timestamp, update policy and fallback behaviour. The correct response may be to pause a dependent action rather than silently substitute another price. Document the policy before an incident, and distinguish the data producer’s responsibilities from the application’s own safety checks.
Keep the evidence in view.
ethereum.org — source & further reading ↗Checked for this edition on 7 October 2026. Examples are illustrative unless stated otherwise. Read our editorial standards.
Another angle.
Liquidity has a location on the price curve
Why the headline value in a pool can conceal where trading depth actually sits.
Read a DeFi position as a chain of dependencies
One balance can depend on more than one protocol staying functional.