Claude Fable 5 vs GPT-5.5: Which Is Better for Coding? (2026)

head-to-head

Metric	Claude Fable 5	GPT-5.5
SWE-bench Verified	95.0%	82.6%
SWE-bench Pro	80.3%	58.6%
Terminal-Bench	—	82.7% (TB2.0)
Input $ / 1M	$10	—
Context	1M	—
Open weights	No	No
Maker	Anthropic	OpenAI

when to pick each

Pick Claude Fable 5 if

Mythos-class flagship for long-horizon agentic runs: the model to reach for when a task spans hours and hundreds of tool calls and has to actually finish.

Pick GPT-5.5 if

OpenAI's strongest agentic coder, with the deepest tooling and ecosystem breadth of the closed labs.

Full reviewsClaude Fable 5, decoded

Ranked on our AI Coding Leaderboard, updated 2026-07-03. Scores are confirmed against primary sources; prices are per 1M input tokens and can change.

Primary sources

AnthropicGENZ TECH — Claude Fable 5 returns — SWE-bench Verified 95.0% (vals.ai independent eval) is the highest confirmed score of any model. SWE-bench Pro 80.3% uses Anthropic's own scaffolding and is contested. Restored Jul 1, 2026 after a 20-day export-control suspension. Pricing $10/$50 per 1M.
OpenAIvals.ai — SWE-bench Verified (independent) — Verified score from vals.ai independent eval; Pro is OpenAI-reported (rivals flag possible memorization on Pro).
BenchmarkSWE-bench — the real-GitHub-issue benchmark

$ quick-answers

Is Claude Fable 5 better than GPT-5.5 for coding?

Claude Fable 5 scores higher on SWE-bench Verified (95.0% vs 82.6%) and SWE-bench Pro, so it is the stronger coder on current benchmarks.

Which is cheaper, Claude Fable 5 or GPT-5.5?

Public per-token pricing isn't confirmed for both, so we don't print a price comparison yet.

Should I use Claude Fable 5 or GPT-5.5?

Claude Fable 5 for the hardest, highest-stakes coding; GPT-5.5 when you want the best value or are running high volume. Both are frontier-class in 2026.