Claude Fable 5 vs Claude Opus 4.8

Pick two tools from the same category to compare side-by-side.

	Claude Fable 5 Anthropic's most capable widely released model, built for demanding reasoning and long-horizon agentic work.	Claude Opus 4.8 Anthropic's Opus-tier model (May 2026) with improved coding, agentic, and honesty behavior over Opus 4.7.
Category	model	model
Vendor type	commercial	commercial
Pricing	usage	usage
Strengths	+ Vendor-stated state-of-the-art on nearly all tested benchmarks, with the lead growing on longer, more complex tasks + 1M-token context window and up to 128k output tokens per request + Built for long-horizon autonomous agent work with memory tool, compaction, and programmatic tool calling + Server-side fallback parameter and fallback credit simplify refusal handling	+ Vendor-reported gains on coding and agentic benchmarks (Terminal-Bench 2.1, 84% on Online-Mind2Web) + Improved honesty; more likely to acknowledge missing information and flag flaws in its own code + Standard pricing unchanged from Opus 4.7 ($5 input / $25 output per million tokens), with a cheaper fast mode than before
Tradeoffs	− Premium pricing: $10 per million input tokens and $50 per million output tokens − Safety classifiers can refuse requests (vendor says under 5% of sessions on average, sometimes catching harmless ones), so integrations must handle stop_reason refusal − 30-day data retention required; not available under zero data retention	− Superseded as Anthropic's top model by Claude Fable 5 (June 2026) for the most demanding long-horizon work − API-only commercial model; no open weights
Used in stacks	0	0

Claude Fable 5 vs Claude Opus 4.8

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