GPT-5.6 Terra

GPT-5.6 Terra is OpenAI's balanced daily driver in the GPT-5.6 family, not the frontier Sol row. Rechecked 2026-08-18: developers.openai.com/api/docs/models still says start with GPT-5.6 Sol, then lists Terra as the mid tier. The first-party GPT-5.6 Terra card prints 400,000 context, 128,000 max output, and $2.50 input / $15.00 output per 1M tokens (cached input $0.25). Knowledge cutoff on that card is February 16, 2026. Reasoning effort tops at xhigh. Do not invent a Terra-only ultra/subagent crown from the Sol page.

Compare GPT-5.6 Sol if you wanted the live frontier, GPT-5.6 Luna if you wanted the cheap/fast sibling, and GPT-5.2 if you wanted the previous billed snapshot.

Key Features

• Balanced 5.6 daily driver: Docs place Terra between Sol frontier and Luna cheap/fast.
• Printed context: 400k input / 128k output on the Terra card we opened.
• Printed dollar row: $2.50 / $15.00 per 1M, cached input $0.25.
• Effort up to xhigh: Recheck the Terra card. Do not paste Sol max / ultra onto Terra.

Use Cases

• People who wanted GPT-5.6 without paying Sol $5 / $30.
• People comparing leftover GPT-4o $2.50/$10 vs live Terra $2.50/$15.
• People who only had a Sol page and needed the mid-tier sibling.

Limitation: We did not re-run Sol benches on Terra or invent a 2026 Cerebras speed claim.

Pricing

GPT-5.6 Terra card on 2026-08-18.

If a leftover blog only mentions Sol, treat Terra as the printed daily-driver row.

Getting Started

1. Open the GPT-5.6 Terra card and note $2.50 / $15 and 400k context.
2. Recheck GPT-5.6 Sol if you wanted the live frontier.
3. Recheck GPT-5.6 Luna if you wanted the cheap/fast row.
4. Do not paste Sol max / ultra onto Terra.

Frequently Asked Questions

Is Terra the start-here model?

No. The models index still starts at GPT-5.6 Sol. Terra is the balanced sibling.

Same as GPT-4o at $2.50?

No. GPT-4o is a leftover omni snapshot at $2.50 / $10. Terra is the live 5.6 mid tier at $2.50 / $15.

Same as Luna?

No. Luna is the cheap/fast 5.6 row at $1 / $6 with a smaller 128k context.

Alternatives

• GPT-5.6 Sol: Live OpenAI frontier.
• GPT-5.6 Luna: Cheap/fast 5.6 sibling.
• GPT-5.2: Previous billed snapshot.

Tips

1. Quote $2.50 / $15 and 400k from the Terra card, not the Sol page.
2. Call Terra the daily driver, not the frontier.
3. Recheck Luna if cost matters more than the 400k window.

Conclusion

GPT-5.6 Terra is the live balanced daily driver in the GPT-5.6 family at $2.50 / $15 with a 400k context, not the Sol frontier. Start at the Terra card, then decide whether GPT-5.6 Sol or GPT-5.6 Luna already covers the path you need.