Claude Fable 5.1 vs Gemini 4 Argon
| Benchmark | Fable 5.1 | Gemini 4 Argon |
|---|---|---|
| AutomationBench-AA | 54.7 | 77.5 |
| GDPval-AA (work tasks) 2.1 | 52.3 | 56.2 |
| AA Analyst Agent | 57.5 · max | 48.8 |
| Terminal-Bench 4.0 | 44.9 | 57.1 |
| Terminal-Bench Science 0.1 | 43.3 · max | 52.9 |
| AA-Briefcase 1.1 · Elo | 1,527.7 | 1,485.8 |
| AA-LCR (long context) 1.1 | 84.7 | 79.7 |
| FrontierCode 1.1 | 49 · max | 43.5 |
| Harvey LAB-AA 1.1 | 6.4 · max | 3.9 |
| SWE-bench Pro (v2 full) | 99.1 · high | 99.2 |
| SWE-bench Pro (v2 hard) | 92.2 · high | 92.2 |
| EBR Bench | 57.1 · max | 64.8 |
| Furniture Assembly | 70 · max | 72.5 |
| AutomationBench · Zapier run | — | 51.3 |
| τ³-Banking · AA | 41 | — |
| ITBench SRE | 49.5 · max | — |
| SpireClimb | 2 · max | — |
| SpireClimb StS1 A20 Heart | 0 · max | — |
| SpireClimb StS2 A10 | 4 · max | — |
Specs
| Spec | Fable 5.1 | Gemini 4 Argon |
|---|---|---|
| Input, per 1M | $10 | !$2 |
| Output, per 1M | $50 | !$10 |
| Cost per task? | $2.98 | $1.99 |
| Speed, tok/s | 56 | 84 |
| Context | 1M | 1M |
| Weights | Closed | Closed |
| Released | Sep 2026 | Oct 2026 |
| See images | ✓ | ✓ |
| Read PDFs | Partial | ✓ |
| Hear audio | — | ✓ |
| Watch video | — | ✓ |
| Call tools | ✓ | ✓ |
| Force a tool call | Partial | Partial |
| Return strict JSON | ✓ | ✓ |
| Search the web | ? | ✓ |
| Run code | ? | ✓ |
| Use a computer | ? | ? |
What breaks when you switch
Synchronous output stops at 65,536›
With background false, output limits above 65,536 tokens return HTTP 400; stay at or below that limit.
Sampling parameters are ignored›
temperature, top_p and top_k are ignored; remove them from requests.
No explicit caching›
Explicit caching is unavailable; omit explicit cache requests.
Replace forced tool_choice›
Forced tool_choice returns HTTP 400; use auto with an explicit instruction and strict tools, or JSON outputs.
Adaptive thinking is always on›
Disabled thinking or manual budget_tokens returns HTTP 400; omit thinking or use adaptive thinking.
No non-default sampling values›
Non-default temperature, top_p or top_k returns HTTP 400; omit non-default sampling values.
Requires 30-day data retention · Claude API›
A Claude API organization or workspace without 30-day retention receives HTTP 400; configure workspace retention or contact the Anthropic account team.
Thinking blocks bind to conversations›
Where conversation binding is enforced, replaying an invalidated block returns HTTP 400; use the documented drop_block control to continue without it.
No assistant prefill›
Assistant prefill returns HTTP 400; use system prompt instructions instead.