One model fixed the bug 3.4x faster. The other did it for less than a dollar. The Cline team took a real bug from their own repo and threw two frontier models at it: Kimi K3 and Claude Fable 5. Same prompt, same setup, a single run each. Both fixed it, and the trade-offs between them tell you exactly which one to reach for.
Round 1: speed
Fable 5 went straight at it. It finished in 3.5 minutes with 18 tool calls. Kimi K3 took 12 minutes and 34 tool calls to land the same fix. That makes Fable 3.4x faster with nearly half the tool calls.
Round 2: cost
The bill flips the story. Kimi's run cost 92 cents. Fable's cost $2.13. Kimi comes out 2.3x cheaper, and the reason is list price: Kimi K3 runs $3 per million input tokens and $15 per million output, versus Fable 5 at $10 in and $50 out.
The crazy part: tokens
Here is where it gets interesting. Kimi burned 1.2 million tokens on the run while Fable only used 730K. Kimi used way more tokens and still cost less than half as much.
That token gap is by design. Kimi K3 is trained with reinforcement learning, which means it learned by trial and error to double check its own work before finishing. More thinking, slower output, but the low per-token price means it still comes out cheaper overall.
So which one should you pick?
If you build by the hour, Fable's speed pays for itself. Waiting 12 minutes for a fix you could have had in 3.5 adds up fast when you are in the loop.
If you are running agents at volume overnight, Kimi's price wins. Nobody is watching the clock at 3am, but somebody is paying the token bill.
The real takeaway is that there is no single winner here. Speed and price are now a genuine choice between frontier models, and an open model at $3 in, $15 out sitting this close to Claude on a real bug fix is exactly why this space is getting interesting.