Teamday

Chat & Reasoning Model · OpenAI

GPT-5.6 (Sol, Terra, Luna)

GPT-5.6 is OpenAI's value family in Teamday below GPT-6 Astra (September 3, 2026), offered in three variants: Sol, the flagship for the most demanding reasoning, coding, and agentic work; Terra, the balanced variant with lower cost and latency than Sol; and Luna, the efficient variant for fast, high-volume work. All three run on the Codex harness with reasoning effort from none up to max. OpenAI cut prices on all three tiers in July and August 2026, and retired GPT-5.4 from Codex on August 31, 2026.

Use GPT-5.6 (Sol, Terra, Luna) in Teamday →All models

At a glance (verified 2026-09-05)

Vendor
OpenAI
Type
Chat & Reasoning Model
Pricing
Sol (promo through Nov 21, 2026): Short: $4 in / $0.40 cache hits / $5 cache writes / $20 out. Long (>272K input): $8 in / $0.80 cache hits / $10 cache writes / $30 out per 1M tokens.

Best for

Demanding reasoning and coding (Sol)Balanced capability and cost (Terra)Fast high-volume work (Luna)Agentic work

How to use GPT-5.6 (Sol, Terra, Luna) in Teamday

Pick GPT-5.6 in Teamday's chat model picker on the Codex harness and choose the Sol, Terra, or Luna variant; Sol is the default variant, while GPT-6 Astra is the recommended pick for the hardest work.

Harness: codex →Max →Daisy →

Frequently asked questions

What are the GPT-5.6 variants?

Sol is the flagship for the most demanding reasoning, coding, and agentic work; Terra is the balanced variant with lower cost and latency than Sol; Luna is the efficient variant for fast, high-volume work.

How much does GPT-5.6 cost?

Per 1M tokens, short context: Sol $4 in / $0.40 cache hits / $20 out (promotional, guaranteed through November 21, 2026 — down from $5 / $30 at the July 9, 2026 launch, cut on August 21), Terra $2 / $0.20 / $12 (cut July 30), Luna $0.20 / $0.02 / $1.20 (cut 80% on July 30). Long context (over 272K input tokens): Sol $8 / $0.80 / $30, Terra $4 / $0.40 / $18, Luna $0.40 / $0.04 / $1.80. Cache writes are billed at 1.25x uncached input (Sol $5, Terra $2.50, Luna $0.25 short context).

Should I pick GPT-5.6 or GPT-6 Astra?

GPT-6 Astra (September 3, 2026) is the more capable model for the hardest reasoning, coding, and computer-use work at $10 / $50 per 1M tokens — 2.5x Sol. GPT-5.6 Sol at $4 / $20 remains the value pick for demanding but routine agent work, and Terra and Luna cover balanced and high-volume tiers.

Is GPT-5.4 still available in Codex?

No — OpenAI retired GPT-5.4 from Codex on August 31, 2026. GPT-5.6 (Sol, Terra, or Luna) is the current family on Teamday's Codex harness.

Can I use GPT-5.6 in Teamday?

Yes — all three GPT-5.6 variants run on Teamday's Codex harness, with reasoning effort selectable from none to max.

Related

GPT-5.6 (Sol, Terra, Luna) is one of the models Teamday's AI employees already run — no API keys, no infrastructure.

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