Claude Fable 5.2 vs Opus 5.5

Claude Fable 5.2 launched on November 9, 2026, as Anthropic's most capable generally available model, alongside Claude Mythos 5.2 — the same underlying model with fewer safeguards, open only to vetted organizations [official]. Fable 5.2 is available on paid Claude plans, in Claude Code, on the Claude Platform as claude-fable-5-2, and through AWS, Google Cloud, and Microsoft Azure [official].

The pitch is capability at a lower price than its predecessor: $8 per million input tokens and $40 per million output tokens, down from $10 and $50 for Fable 5.1, with output up to 30% faster [official]. An optional fast mode doubles both rates to $16/$80 for up to 2.5x token generation speed [official].

On Anthropic's own benchmark table, Fable 5.2 leads Opus 5.5 on most rows — 49.1% vs 45.5% on FrontierCode 2.0, 69.9% vs 62.3% on FrontierSWE v2, 74.2% vs 67.7% on Humanity's Last Exam — while Opus 5.5 keeps the higher AA-Briefcase Elo, 1800 to 1785 [official]. Every one of those numbers is vendor-reported: Anthropic ran the table, and the effort levels differ by row. The one independent signal so far, Artificial Analysis, puts Fable 5.2 at 65 on its Intelligence Index against 59 for Opus 5.5 [reported].

Two limits worth knowing before you switch. First, Fable 5.2's safeguards block most cybersecurity work and most research-biology tasks; blocked queries fall back to Opus 4.8 or Opus 5 instead [official]. Second, most customers accept 30-day retention of prompts and completions for safety monitoring; zero data retention needs Enterprise Frontier Safeguards, currently in private beta [official].

Claude Opus 5.5 launched on September 22, 2026, as the first model in Anthropic's 5.5 family [reported]. It costs $4 per million input tokens and $20 per million output tokens on the standard API, with cache reads at $0.20 per million [reported] — exactly half of Fable 5.2 on every line.

Opus 5.5's case is not that it wins benchmarks — on Anthropic's table it trails Fable 5.2 on most rows [official]. Its case is that Anthropic still tells most users to start there: "for most coding and knowledge tasks, we recommend that users start with Claude Opus 5.5, our strongest daily driver" [official]. Same 1M-token context window and 128K-token max output as Fable 5.2 [reported], a medium default effort instead of high [reported], and half the price. For everyday coding and knowledge work, that is the model to beat — and Fable 5.2 has to earn its 2x premium on the specific task in front of you.

Fable 5.2 costs $8 per million input tokens and $40 per million output tokens [official]. Opus 5.5 costs $4 and $20 [reported]. The ratio is a clean 2x at every tier: fast mode is $16/$80 for Fable 5.2 [official] against $8/$40 for Opus 5.5 [reported], batch is $4/$20 against $2/$10 [reported], and cache reads are $0.20 per million for both [reported].

A concrete example at list price: 1 million input tokens plus 200,000 output tokens costs $16.00 on Fable 5.2 ($8 + $8) and $8.00 on Opus 5.5 ($4 + $4). But per-token price is not per-task price. Anthropic says Fable 5.2 at High effort matched Opus 5.5 at Max effort on FrontierCode 2.0 — 45.3% against 45.5% — for roughly half the cost per task [official], because it reaches the same score with fewer tokens. If your work runs Opus 5.5 at Max effort today, Fable 5.2 may be cheaper per finished task despite the 2x sticker; if it runs at the medium default, Opus 5.5 stays cheaper.

Choose Opus 5.5 if you want the default: everyday coding, knowledge work, and long-running agents at half the per-token price, with Anthropic's own recommendation behind it [official]. It is also the safer pick on knowledge-work Elo, where it still leads Fable 5.2 [official].

Choose Fable 5.2 if Opus 5.5 is falling short at high effort on genuinely hard work — large refactors, multi-agent orchestration, research-grade reasoning — and the benchmark gaps above (FrontierCode, FrontierSWE, Humanity's Last Exam) match the shape of your task [official]. The 2x price buys the top of Anthropic's table, not a better everyday model.

The honest caveat: this comparison is one day old. The launch announcement is from November 9, 2026, and the same-day comparison pages now ranking for this query (beri, kulimo) all repeat Anthropic's table with different framing [reported]. The numbers on this page come from Anthropic's own announcement, read directly, so they hold up even where the new pages disagree — but independent testing is barely a day old, and the verdict that matters is your own workload run against both models.