GPT-5.3-Codex is retired — migrate to the three GPT-5.6 tiers
Calling gpt-5.3-codex now returns model_not_supported, and the official error message points directly to gpt-5.6-sol / gpt-5.6-terra / gpt-5.6-luna. This page covers the impact and the migration steps.
What happened
GPT-5.3-Codex (released 2026-02-05) was OpenAI's agentic coding flagship: SWE-Bench Pro 56.8%, Terminal-Bench 2.0 77.3%, real-time steering while running. In August 2026 the model was retired: calls return model_not_supported — "Model 'gpt-5.3-codex' is no longer available. Please use gpt-5.6-sol / gpt-5.6-terra / gpt-5.6-luna". This is not a regional restriction; it's a global shutdown.
Official replacement: the three GPT-5.6 tiers
sol is the flagship now $4/$20 per million tokens per the 2026-09-12 archive of the official pricing page, promotional at least through 2026-11-21, plus a 2.5×-faster Fast mode; terra is the balanced workhorse ($2/$12, cut 20% on 07-30); luna is the lightweight high-frequency tier ($0.20/$1.20, cut 80% on 07-30). All three carry a 1,050,000-token API context (922,000 max input, 128,000 max output) and beat 5.3-Codex across coding and agent benchmarks.
How to migrate
Replace gpt-5.3-codex everywhere it appears — saved configs, custom agents, CI scripts and cron jobs: use gpt-5.6-terra for everyday coding, gpt-5.6-sol for hard tasks and long agent loops, and gpt-5.6-luna for high-frequency light tasks. SDK, endpoint and keys stay exactly as they are — only the model id changes.
On QCode
gpt-5.3-codex is unavailable on every platform alike. QCode sells all three GPT-5.6 tiers (sol / terra / luna — all with heavy real usage over the last 30 days) at official list price × service rate, and the same key switches tiers directly.
FAQ
Can I still use gpt-5.3-codex?
No. The API returns model_not_supported outright and points to the three replacements: gpt-5.6-sol / terra / luna. This is not a regional or account issue — it's a global shutdown.
Which tier should I migrate to?
terra ($2/$12) for everyday coding; sol (now $4/$20, promo at least through 2026-11-21) for hard debugging and long-horizon agent tasks; luna ($0.20/$1.20) for high-frequency light tasks. Split by task type — don't force one tier onto everything.
Do I need to change code?
Only the model id. The OpenAI-compatible endpoint, SDK and keys all stay the same; QCode users switch tiers with the same key — no re-provisioning needed.
Migrate to the three GPT-5.6 tiers
QCode sells sol / terra / luna with unified billing at official list price × service rate — one key covers all seven model families.
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