Claude Opus 5 vs GPT-6 Astra
| Benchmark | Opus 5 | GPT-6 Astra |
|---|---|---|
| MMMU-Pro (vision) | 81.6 | 85.1 |
| Chartography | 27.3 · max | 71 · max |
| GDP.pdf · AA all-pass | 20 | 30.4 |
| Arena Document · overall | 1,516.3 · high | 1,467.5 · max |
| Arena Vision · overall | 1,319.6 · high | 1,279.9 · max |
Specs
| Spec | Opus 5 | GPT-6 Astra |
|---|---|---|
| Input, per 1M | $5 | $10 |
| Output, per 1M | $25 | $50 |
| Cost per task? | $2.19 | $1.54 |
| Speed, tok/s | 51 | 59 |
| Context | 1M | 1.05M |
| Weights | Closed | Closed |
| Released | Jul 2026 | Sep 2026 |
| See images | ✓ | ✓ |
| Read PDFs | Partial | Partial |
| Hear audio | — | — |
| Watch video | — | — |
| Call tools | ✓ | ✓ |
| Force a tool call | Partial | Partial |
| Return strict JSON | ✓ | ✓ |
| Search the web | ? | ✓ |
| Run code | ? | ✓ |
| Use a computer | ? | ✓ |
What breaks when you switch
Opus 5 → GPT-6 Astra
Monitoring can return HTTP 403›
Misalignment monitoring can return HTTP 403 before streaming or errors after output; match misalignment_policy_violation and handle stream errors.
No none reasoning effort›
The none reasoning effort is unsupported on GPT-6 Astra and GPT-6.1 Sol; use low instead.
Remove unsupported sampling parameters›
When reasoning effort is not none, remove temperature, top_p and top_logprobs, plus Chat Completions logprobs or Responses output logprobs inclusion.
GPT-6 Astra → Opus 5