Claude Fable 5 vs GPT-5.5
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
Claude Fable 5
Anthropic · Jun 2026
The first GA model of Anthropic's Mythos class — a tier above Opus — and the current SWE-bench Verified leader, at $10/$50 per 1M tokens.
GPT-5.5
77.2OpenAI · Apr 2026
OpenAI's flagship reasoning model with a 1M-token context window, built for hard coding, science and long-horizon agentic work.
The verdict
Claude Fable 5 wins 1 of the 1 benchmarks these models share, against 0 for GPT-5.5. GPT-5.5 is about 1.8x cheaper per blended million tokens (3:1 input:output mix).
Benchmark head-to-head 1–0
Specs & pricing
| Claude Fable 5 | GPT-5.5 | |
|---|---|---|
| modhub Index | — | 77.2 |
| Input price / 1M | $10 | $5 |
| Output price / 1M | $50 | $30 |
| Context window | 1M | 1M |
| Max output | 128K | 128K |
| Open weights | no | no |
| Reasoning model | yes | yes |
| Multimodal input | text, image | text, image |
| Knowledge cutoff | Jan 2026 | Jan 2026 |
| Released | Jun 2026 | Apr 2026 |
| Example monthly cost* | $175.00 | $95.00 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, Claude Fable 5 or GPT-5.5?
- Claude Fable 5 wins 1 of the 1 benchmarks these models share, against 0 for GPT-5.5. GPT-5.5 is about 1.8x cheaper per blended million tokens (3:1 input:output mix).
- Which is cheaper, Claude Fable 5 or GPT-5.5?
- Claude Fable 5 costs $10/$50 per million input/output tokens, while GPT-5.5 costs $5/$30. For a typical workload of 10M input and 1.5M output tokens per month, that's $175.00 versus $95.00.
- Which model is better for coding, Claude Fable 5 or GPT-5.5?
- On SWE-bench Verified — the standard agentic-coding benchmark — Claude Fable 5 scores ~95% versus 82.6% for GPT-5.5, making Claude Fable 5 the stronger pick for coding agents.