Model comparison
Claude Fable 5.1 vs Gemini 4 Argon (restricted preview)
Anthropic against Google, compared on context, price, and attributed benchmark results.
Recorded profile verification October 1, 2026Individual provider fields may changeEvidence confidence: Insufficient data — see receipts below
Anthropic
Claude Fable 5.1
Frontier
Gemini 4 Argon (restricted preview)
Frontier
| Specification | Claude Fable 5.1 | Gemini 4 Argon (restricted preview) |
|---|---|---|
| Provider | ||
| Provider | Anthropic | |
| Tier | ||
| Tier | Frontier | Frontier |
| Context window | ||
| Context window | 1M | Not verifiedUnverified |
| Max output | ||
| Max output | 128K | Winner: 1M |
| Input / 1M tokens | ||
| Input / 1M tokens | $10 | Not verifiedUnverified |
| Output / 1M tokens | ||
| Output / 1M tokens | $50 | Not verifiedUnverified |
| Weights | ||
| Weights | Closed | Closed |
| Parameters | ||
| Parameters | Not verifiedUnverified | Not verifiedUnverified |
| Reasoning levels | ||
| Reasoning levels | low, medium, high, xhigh, max | Not verifiedUnverified |
| Modalities | ||
| Modalities | text, image | text, image, video |
| API model id | ||
| API model id | claude-fable-5-1 | Not verifiedUnverified |
| Released | ||
| Released | September 1, 2026 | September 30, 2026 |
| Artificial Analysis Intelligence Index [max] · source date Claude Fable 5.1: 2026-10-01 | ||
| Artificial Analysis Intelligence Index [max] · source date Claude Fable 5.1: 2026-10-01 | 53 | Not verifiedUnverified |
| Artificial Analysis Intelligence Index [high] · source date Gemini 4 Argon (restricted preview): 2026-10-01 | ||
| Artificial Analysis Intelligence Index [high] · source date Gemini 4 Argon (restricted preview): 2026-10-01 | Not verifiedUnverified | 53 |
| Humanity's Last Exam · source date Claude Fable 5.1: 2026-09-01 | ||
| Humanity's Last Exam · source date Claude Fable 5.1: 2026-09-01 | 65 | Not verifiedUnverified |
| Terminal-Bench 2.1 · source date Claude Fable 5.1: 2026-09-26 | ||
| Terminal-Bench 2.1 · source date Claude Fable 5.1: 2026-09-26 | 91.4 | Not verifiedUnverified |
| DeepSWE 1.1 · source date Claude Fable 5.1: 2026-09-03 | ||
| DeepSWE 1.1 · source date Claude Fable 5.1: 2026-09-03 | 67.4 | Not verifiedUnverified |
| DeepSWE 1.1 · source date Gemini 4 Argon (restricted preview): 2026-10-01 | ||
| DeepSWE 1.1 · source date Gemini 4 Argon (restricted preview): 2026-10-01 | Not verifiedUnverified | 77.9 |
| AutomationBench · source date Gemini 4 Argon (restricted preview): 2026-10-01 | ||
| AutomationBench · source date Gemini 4 Argon (restricted preview): 2026-10-01 | Not verifiedUnverified | 51.3 |
| LVBench · source date Gemini 4 Argon (restricted preview): 2026-10-01 | ||
| LVBench · source date Gemini 4 Argon (restricted preview): 2026-10-01 | Not verifiedUnverified | 91.7 |
Dates beside benchmark scores refer to the linked source’s publication or capture date unless that source explicitly states when it measured the result. A shared URL alone does not establish comparable runs; unverified setups are marked. Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.
Benchmark receipts
Where each score comes from, and how far it can be compared across models.
- Source date2026-10-01
- Source date2026-10-01
- Source date2026-10-01Google (vendor-reported; not in Datacurve’s September 22 board)
Agentic software engineering: pass@1 on real repo tasks with reported cost per completed task.
Directly comparable
- Source date2026-10-01Artificial Analysis (Gemini 4 Argon (high))
Composite index blending reasoning, knowledge, and coding evals into one 0–100 score.
Comparable with caveatOnly same-version scores are comparable. v4.3.2 was rebaselined (the top score fell from 66 on v4.1.1 to ~58), so v4.1.1 figures must not be compared with v4.3.2 figures — check the cited source and its date.
- Source date2026-10-01Artificial Analysis (Claude Fable 5.1 (max with fallback))
Composite index blending reasoning, knowledge, and coding evals into one 0–100 score.
Comparable with caveatOnly same-version scores are comparable. v4.3.2 was rebaselined (the top score fell from 66 on v4.1.1 to ~58), so v4.1.1 figures must not be compared with v4.3.2 figures — check the cited source and its date.
- Source date2026-09-26Artificial Analysis Terminal-Bench 2.1 (independent, Terminus 2, max effort)
Agentic terminal work: multi-step tasks executed in a sandboxed shell environment.
Comparable with caveatNot comparable with Terminal-Bench 3.0 or 4.0 (different task sets) or v1; harness configuration (container, time limits) also shifts results.
- Source date2026-09-03OpenAI GPT-6 Astra launch table quoting a cross-provider result; not a direct Datacurve row (Cross-provider quotation; Fable harness, effort and experiment date unverified)
Agentic software engineering: pass@1 on real repo tasks with reported cost per completed task.
Directly comparable
- Source date2026-09-01Anthropic Fable 5.1 announcement (vendor, with tools; 60.9 no tools) — Anthropic's later Opus 5.5 table lists 65.6; conflict preserved
Frontier-knowledge ceiling: extremely hard multi-domain questions written to be near-impossible without deep expertise.
Comparable with caveatSubset/tool configurations (text-only vs with-tools) differ between vendors and materially change scores; must match configuration to compare.
Pricing tiers
Claude Fable 5.1: Standard $10/$50 per MTok with no long-context surcharge. Cache reads $0.25, versus Fable 5's $1; 5-minute writes $12.50 and 1-hour writes $20. Batch $5/$25. US-only inference adds 10% where supported. Adaptive thinking is always on, default effort high; knowledge cutoff Jun 2026. Retirement not sooner than September 1, 2027.
Gemini 4 Argon (restricted preview): Google announced a future introductory API price of $2 input / $10 output per million tokens, with 95% off cached input. After the introductory period: $4/$20. These are announced launch rates; general API availability and the introductory end date are not confirmed. Current purchasable token rates are therefore left unverified.
Claude Fable 5.1
Claude Fable 5.1 is Anthropic's model for the most demanding reasoning and long-horizon agentic work at $10/$50 — Anthropic now recommends Opus 5.5 as the default for most workloads.
Best for
- Frontier agents
- Hardest reasoning work
- Fable 5 workloads at the same price
Watch out
Standard token rates are 2.5x Opus 5.5's. Forced tool use errors; thinking blocks are model/conversation-bound, so editing earlier turns or switching models can invalidate them. Display updates and per-message effort are beta. Match benchmark settings and evaluate pinned workloads before migrating.
Gemini 4 Argon (restricted preview)
Google’s announced frontier model, initially restricted to trusted cyber defenders in the Fairwind program while broader safeguards and access are prepared.
Best for
- Long-horizon coding research
- Enterprise knowledge-work evaluation
Watch out
Restricted preview, not generally available. Google’s API model list does not yet publish a stable model ID or verified context limit. The 1M figure here is the announced maximum output, not a confirmed input context window.
When the cheaper one wins
One of these rows is missing a verified output price, so this page will not name a cheaper winner. Run the model picker against the actual job instead of guessing.
Run the model pickerEvidence confidence: Insufficient data
How strong and complete the evidence behind this comparison is — not a prediction of which model is better. Hard limitations apply: missing pricing; evidence too sparse.
- Pricing incomplete — No verified token pricing for Gemini 4 Argon (restricted preview).
- 2/5 core specs verified on both sides — Not published for at least one side: context window, parameter count, reasoning levels.
- No directly aligned benchmark setup — No benchmark has matching cited sources, source dates, units, effort and recorded run details on both models.
- Verified within the last 90 days — Older of the two catalog checks was 25 days ago.
- Both models carry source citations — Each side has at least two catalog sources on record.
Source receipts
Each catalog figure was checked against the provider or an independent second source on the date shown.
- Claude Fable 5.1: Claude model overview — whole-profile source check October 1 (accessed 2026-10-01)
- Claude Fable 5.1: Claude current API pricing, caching and inference geography (accessed 2026-10-01)
- Claude Fable 5.1: Anthropic pricing — Fable 5.1/Mythos 5.1 $10/$50 (accessed 2026-09-03)
- Claude Fable 5.1: Anthropic models overview — Fable 5.1 (1M context, 128K output) (accessed 2026-09-03)
- Claude Fable 5.1: Anthropic — Claude Fable and Mythos 5.1 announcement (accessed 2026-09-26)
- Claude Fable 5.1: Anthropic models overview — Opus 5.5 default; Fable 5.1 for demanding reasoning (accessed 2026-09-26)
- Claude Fable 5.1: Anthropic effort documentation (Fable 5.1 selectable effort) (accessed 2026-10-01)
- Gemini 4 Argon (restricted preview): Google primary profile — whole-record source check October 1 (accessed 2026-10-01)
- Gemini 4 Argon (restricted preview): Gemini current API pricing and cache-storage tiers (accessed 2026-10-01)
- Gemini 4 Argon (restricted preview): Google announcement and availability (accessed 2026-10-01)
- Gemini 4 Argon (restricted preview): Gemini API model catalog (no general Argon endpoint) (accessed 2026-10-01)
- Gemini 4 Argon (restricted preview): Text Arena preview evaluation (accessed 2026-10-01)
Related comparisons
- Claude Fable 5.1 vs Claude Haiku 4.5
- Claude Fable 5.1 vs Claude Mythos 5.1
- Claude Fable 5.1 vs Claude Opus 5
- Claude Fable 5.1 vs Claude Opus 5.5
- Claude Fable 5.1 vs Claude Sonnet 5
- Claude Fable 5.1 vs Claude Sonnet 5.5
Diving deeper on one model? Claude Fable 5.1 · Gemini 4 Argon (restricted preview)
Common questions
Claude Fable 5.1 vs Gemini 4 Argon (restricted preview)
Answered from the verified figures on this page rather than general guidance.
Should I use Claude Fable 5.1 or Gemini 4 Argon (restricted preview)?
Next step
Choosing between them
The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.
These two models match on every verified catalog figure — the decision comes down to provider preference, availability, and workload fit rather than published numbers.
Choosing a harness rather than a model — Cursor, Copilot, Claude Code, Windsurf, or Lovable? Compare agentic harnesses · Latest releases.