No shared harness
No published benchmark runs Claude Fable 5.1 and Kimi K3 under the same harness. Anthropic, Moonshot and third parties have not co-evaluated the two on Terminal-Bench 4.0 or any other agentic coding benchmark. State the absence before showing any score.
Where Fable 5.1 wins
On published benchmarks Claude Fable 5.1 leads the entire Anthropic launch table on Terminal-Bench 4.0 (55.8%), CursorBench 3.2.0 (73.4%) and Terminal-Bench-Science 0.1 (52.6%). Kimi K3 has not been evaluated on these benchmarks. The headline-score advantage belongs to Fable 5.1, but only on Anthropic's harness.
Where Kimi K3 wins
Kimi K3 ships open weights under the Kimi K3 licence and runs at $3 per 1M input and $15 per 1M output, a third of the Fable 5.1 input price. For workloads that can tolerate lower peak scores, the price advantage is large enough that the per-task cost of running Kimi K3 on a 1M-token agent is a fraction of the Fable 5.1 cost.
Ready to test the workflow?
Create account & add creditsRouting
Both models route through OneInfer. OneInfer provides Kimi K3 with the same OpenAI-compatible endpoint as Fable 5.1. The migration cost between the two is a one-line model-string change.
Frequently asked questions
Is Kimi K3 as good as Claude Fable 5.1?
No benchmark has been published running both under the same harness, so the comparison cannot be answered head-to-head. Anthropic's published scores for Fable 5.1 are the highest on the launch table. Kimi K3 has not been evaluated on those benchmarks. For workloads where price matters more than peak score, Kimi K3 delivers a 1M-token context at roughly a third of the Fable 5.1 input cost.
Put Claude Fable 5.1 to work
Fund a controlled evaluation, start with a prepared prompt, and measure quality and cost on your own workload.