Quick answer
Use Opus 5.5 as the Claude default for production coding. Use Astra when you specifically want OpenAI's highest-capability model and can justify its higher price.
- Opus 5.5
- $4 in / $20 out per MTok
- GPT-6 Astra
- $10 in / $50 out per MTok
- Context
- 1M vs 1.05M
- Verified
- September 23, 2026
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Comparable facts
| Claude Opus 5.5 | GPT-6 Astra | |
|---|---|---|
| Base API price | $4 in / $20 out per MTok | $10 in / $50 out per MTok |
| Context / output | 1M tokens (128K max output) | 1,050,000 tokens (128K max output) |
| Vendor position | Recommended Claude default | Highest-capability GPT-6 |
| Adaptive reasoning | Always on | Configurable; no none setting |
| API model | claude-opus-5-5 | gpt-6-astra |
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02
Benchmark context
Anthropic reports Opus 5.5 at 66.4% on Terminal-Bench 4.0 and 54.4% on FrontierCode v1.1. The same Anthropic comparison table lists Astra at 57.9% and 53.3%, respectively, with the Astra scores marked as reported by OpenAI.
03
Which one should you choose?
Pick Opus 5.5 if Claude Code is your primary agent or if $4/$20 better matches a sustained production workload. Pick Astra for an OpenAI-native stack or when maximum GPT-6 capability matters more than its $10/$50 list price. For the hardest Claude tasks, Anthropic's escalation path is Fable 5.1.
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