Claude Fable 5 vs GLM 5.1

Compare Claude Fable 5 and GLM 5.1 on the metrics that decide an agent workload.

MetricClaude Fable 5GLM 5.1
ProviderAnthropicFireworks AI
Input / 1M$10.00$1.40
Output / 1M$50.00$4.40
Cache read / 1M$1.00 (−90%)$0.26 (−81%)
Reuse-adj @55%$16.29$1.68
Context1M203K
Cache capture93%82%
Warm TTFT280ms (−70%)130ms (−62%)
Quality index9886

Teal marks the better value in each row. Reuse-adjusted assumes 55% prefix reuse and a 25% output share.

Pick Claude Fable 5 when

Pick Claude Fable 5 when it scores higher on the composite quality index, it carries the larger 1M context window, it captures more of the available reuse.

Pick GLM 5.1 when

Pick GLM 5.1 when it is cheaper once prefix reuse is priced in, it answers faster on warm cache hits, it is open-weights for on-prem and regulated lanes.

Verdict

Claude Fable 5 leads on quality while GLM 5.1 leads on reuse-adjusted cost. Send latency- and budget-sensitive volume to GLM 5.1 and reserve Claude Fable 5 for the hard requests. Zumik's aliases route between them automatically under policy.

Claude Fable 5 vs GLM 5.1, answered.

Is Claude Fable 5 or GLM 5.1 cheaper?

At 55% prefix reuse, Claude Fable 5 blends to about $16.29 per 1M tokens and GLM 5.1 to about $1.68. GLM 5.1 is cheaper on that basis.

Which has the larger context window?

Claude Fable 5 has the larger window: 1M vs 203K tokens.

Which captures more reuse?

Claude Fable 5 shows higher measured cache capture (93% vs 82%) in the Zumik corpus.

Let an alias pick for you.

Route to whichever model wins under current policy automatically. Zumik resolves the alias to the best fit per request, so you never hard-code a loser.