article --summary
The summary
The writer tested the newer Fable 5.2 against Fable 5.1 on a long webhook chat, a signature-checking coding task, and a login library repair with three increasingly hard versions. The main difference was refusals: the older model blocked most of the webhook chat and both signature-checker turns, while the newer one completed them without refusal and passed all hidden tests.
On the login repair work the two models scored identically, and output speed came out roughly 30% higher on Fable 5.2 per second of elapsed time. Cost savings were small in practice, with combined estimates differing by about 2%, even though the published per-token price is 20% lower.
The comparison rests on one run per model for each task, so the writer suggests testing both against your own workload before drawing firm conclusions.
Editorial note: This is a summary of an article first published by The New Stack. The full piece is on their site.