GPT-5.6 vs Claude Opus 4.8
One shipped, one still a rumor
Claude Opus 4.8 has officially shipped and is well-documented; GPT-5.6 is still unannounced. This is an honest 'known vs unknown' comparison — wherever GPT-5.6 has no official basis, we mark it 'TBD' and never invent numbers.
Two flagships, in one line
OpenAI's next model. As of June 2026 it is unannounced, surfacing only briefly in Codex logs. Rumored 1.5M context and stronger frontend UI generation, but benchmarks and pricing are all TBD.
Anthropic's currently shipped flagship (May 28, 2026): $5/$25 pricing, native 1M context, Fast Mode at ~2.5× speed and ~3× cheaper, with built-in dynamic workflows and effort control.
Spec comparison
Opus 4.8 figures are official; every unreleased GPT-5.6 cell is marked 'TBD'.
| Spec | GPT-5.6 | Claude Opus 4.8 |
|---|---|---|
| Release status | Unreleased (unannounced) | Shipped 2026-05-28 |
| Context window | TBD (rumored 1.5M) | 1M (native) |
| Pricing / MTok | TBD | $5 / $25 |
| Coding benchmark | TBD | No official SWE-bench score |
| Signature capability | TBD (rumored frontend UI gen) | Dynamic workflows + Fast Mode |
| QCode access | Onboarded at launch · Codex | Supported now · Claude Code |
The 'rumored' notes for GPT-5.6 come from third-party leaks, unconfirmed by OpenAI; Opus 4.8's 'No official SWE-bench score' is a faithful note, not an omission.
✅ What's confirmed
What's certain: Opus 4.8 has shipped and is well-documented — same $5/$25 pricing, 1M context, Fast Mode (~2.5× speed / ~3× cheaper), dynamic workflows and effort control, with Anthropic claiming leadership in agentic coding, reasoning, financial analysis and knowledge work (though no specific SWE-bench score was published). Every number on this side has an official source.
🔮 What's still unverified
Everything about GPT-5.6 — whether it truly has 1.5M context, how strong its frontend UI generation is, when it launches, what it costs — has no official basis yet. Until OpenAI ships it, any 'GPT-5.6 beats/loses to Opus 4.8' verdict is premature. We'll update this page with real benchmarks once it's out.
Don't forget: Mythos is coming too
There's another variable beyond this matchup: Anthropic has confirmed Mythos-class models will reach all customers 'in the coming weeks'. Once GPT-5.6 and Mythos both land, the next comparison could be rewritten entirely.
Access both sides with QCode
No need to pick one. A single QCode API key runs Claude Opus 4.8 in Claude Code and the GPT family in Codex CLI — with GPT-5.6 onboarded as soon as it ships.
export ANTHROPIC_BASE_URL="https://api.qcode.cc"
export ANTHROPIC_AUTH_TOKEN="$QCODE_KEY"
claudenpm install -g @openai/codex
# add QCode profile in ~/.codex/config.toml
codex --profile qcodeComparison FAQ
Can I compare GPT-5.6 and Opus 4.8 benchmarks now?
No. GPT-5.6 isn't out, so there are no official benchmarks. Every GPT-5.6 description here is marked 'TBD' or 'rumored'; only the Opus 4.8 side is confirmed data.
Will GPT-5.6 be stronger than Claude Opus 4.8?
No way to say. Until OpenAI publishes official benchmarks, any verdict is a guess. We'll update the comparison with real data once GPT-5.6 ships.
What is Opus 4.8's SWE-bench score?
Anthropic did not publish a SWE-bench score for Opus 4.8. It emphasizes leadership in agentic coding, reasoning and knowledge work but gave no specific figure for that metric.
Which should I use right now?
If you need something today, Claude Opus 4.8 is the shipped, available, well-documented choice. Once GPT-5.6 launches, you can try it from Codex CLI with the same QCode key — no account change.
One key, miss neither side
Sign up for QCode.cc — use Claude Opus 4.8 today, and GPT-5.6 the moment it ships.