AI Model Picker comparison
Claude Opus 5.5 vs GPT-6 Astra
Both products reached the final shortlist for the same buyer profile — Frontier Reasoning — in the AI Model Picker. Your answers favor maximum capability for hard reasoning, coding, and agentic work — cost is secondary to getting the task done.
Anthropic
Claude Opus 5.5
AA index #1 · $4 / $20 per 1M tokens; cache reads $0.20 per 1M · Not independently rated
OpenAI
GPT-6 Astra
OpenAI flagship · $10 / $50 per 1M tokens (≤272K input); $20 / $75 above · Not independently rated
| What differs | Claude Opus 5.5 | GPT-6 Astra |
|---|---|---|
| Vendor | ||
| Vendor | Anthropic | OpenAI |
| Positioning | ||
| Positioning | AA index #1 | OpenAI flagship |
| Price positioning | ||
| Price positioning | $4 / $20 per 1M tokens; cache reads $0.20 per 1M | $10 / $50 per 1M tokens (≤272K input); $20 / $75 above |
| Editorial rating | ||
| Editorial rating | Not independently rated | Not independently rated |
| Best for | ||
| Best for | Hard reasoning, agentic coding, and knowledge work where quality is the constraint. | Computer-use agents and hard reasoning with vision. |
Features
What each one leads with
The standout capabilities recorded for each product in the recommendation data.
Claude Opus 5.5
- 1M context (verified on profile)
- 128K max output
- Adaptive thinking always on
GPT-6 Astra
- 1.05M context (verified on profile)
- OSWorld 2.0 72.6% (offline, self-reported)
- Image input modality
Trade-offs
Pros and cons, side by side
The strengths and the catches the decision tool already weighs for this buyer profile.
Claude Opus 5.5
Pros
- AA Intelligence Index v4.3.2 57.6 and CursorBench 4.0 57.8% (Max)
- Cheaper than Opus 5 ($4/$20 vs $5/$25)
Cons
- Forced tool use and disabling thinking are breaking changes vs Opus 5
- Closed weights — no self-hosting
GPT-6 Astra
Pros
- 74.1% DeepSWE 1.1 (xhigh) at $4.43/task — #1 on the independent board
- Largest OpenAI training run to date (Stargate)
Cons
- Enterprise tenants get it disabled by default
- AA index v4.3.2 52.7 (max) — below Claude Opus 5.5's 57.6
The verdict
Who should pick which
Assembled from the same recommendation fields the tool scores on — not a universal winner.
Both products are finalists for the same buyer profile, so this is a fit decision rather than a category decision. Claude Opus 5.5 is aimed at hard reasoning, agentic coding, and knowledge work where quality is the constraint. GPT-6 Astra is aimed at computer-use agents and hard reasoning with vision. Neither product has an independently verified rating here, so use the fit criteria and current product evidence rather than a synthetic score.
Choose Claude Opus 5.5 if…
Hard reasoning, agentic coding, and knowledge work where quality is the constraint.
Watch out for
Forced tool use and disabling thinking are breaking changes vs Opus 5
$4 / $20 per 1M tokens; cache reads $0.20 per 1M
Choose GPT-6 Astra if…
Computer-use agents and hard reasoning with vision.
Watch out for
Enterprise tenants get it disabled by default
$10 / $50 per 1M tokens (≤272K input); $20 / $75 above
Common questions
Claude Opus 5.5 vs GPT-6 Astra
Answered from the verified figures on this page rather than general guidance.
Is Claude Opus 5.5 or GPT-6 Astra cheaper?
Which is rated higher, Claude Opus 5.5 or GPT-6 Astra?
Should I choose Claude Opus 5.5 or GPT-6 Astra?
What is the catch with Claude Opus 5.5 and GPT-6 Astra?
A head-to-head answers one question: of the two finalists for this buyer profile, which fits your situation. If neither “best for” line matches, run the full tool — its other profiles exist for different buyers.