Claude Fable 5 vs GPT-5.4

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.	GPT-5.4 OpenAI's more affordable frontier model for coding and professional work, sitting below GPT-5.5.
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	+ Half the per-token price of GPT-5.5 while staying in the frontier coding/professional tier + 1M-token context window with up to 128K output tokens + mini variant targeted at subagent and computer-use workloads for high-volume agent fleets
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	− OpenAI directs complex reasoning and coding to GPT-5.5 instead − Older knowledge cutoff (Aug 31, 2025) than GPT-5.5
Used in stacks	0	0