Claude Opus 5 vs GPT-5.6 Sol
Anthropic's and OpenAI's flagship coding models compared across context, price, coding standing, and where you can run them.
Updated August 28, 2026 · Independent comparison — Claude Opus 5, GPT-5.6 Sol are separate products.
Claude Opus 5
Anthropic's default for complex agentic coding
Claude Opus 5 is Anthropic's default for complex agentic coding and enterprise work, a step-change over Opus 4.8 released July 24, 2026. It carries a 1M-token context window, up to 128K output (up to 300K on the Batch API beta), thinking on by default, and the full effort ladder through max. At $5/$25 per million tokens (cache read $0.50, batch 50% off) it supports zero-data-retention and a research-preview fast mode (up to 2.5x output speed at premium pricing). It runs on the Claude API, Bedrock, Vertex, and Microsoft Foundry, plus Claude Code on Pro/Max.
GPT-5.6 Sol
OpenAI's flagship GPT-5.6 reasoning model
GPT-5.6 Sol is the flagship tier of OpenAI's GPT-5.6 family, tuned for the hardest professional, coding, and research work and strong at command-line, multi-step problems. It offers roughly a 1.05M-token context window, 128K max output, a February 2026 knowledge cutoff, and reasoning effort levels from none through max plus higher max/ultra modes. Its current API price is a promotional $4/$20 per million tokens (down from a $5/$30 list rate) held through November 21, 2026, with a $0.40 cache-read rate; requests over 272K input tokens are billed at 2x input / 1.5x output for the whole request ($8/$30). It is available in ChatGPT Plus and above, and Cursor lists the same promo rate.
Bottom line
Anthropic's and OpenAI's flagship coding models compared across context, price, coding standing, and where you can run them. Choose Claude Opus 5 if you want Anthropic's coding-first flagship with a zero-data-retention option; choose GPT-5.6 Sol if you want the top GPT-5.6 tier at a lower promo output rate ($20 vs $25 per 1M).
Context & Limits
| Feature | Claude Opus 5 | GPT-5.6 Sol |
|---|---|---|
| Context window | 1M (1,000,000 tokens) | ~1.05M (1,050,000 tokens) |
| Max output tokens | 128K (up to 300K on Batch API beta) | 128K |
| Image / vision input | ✓ | ✓ |
| Knowledge cutoff | Not published | February 2026 |
Pricing (per 1M tokens)
| Feature | Claude Opus 5 | GPT-5.6 Sol |
|---|---|---|
| Input | $5.00 | $4.00 (promo; $5.00 list, through 2026-11-21) |
| Output | $25.00 | $20.00 (promo; $30.00 list) |
| Cached input read | $0.50 | $0.40 |
| Long-context surcharge | None (flat to 1M) | >272K input: 2x in / 1.5x out for the whole request ($8/$30) |
| Fast / premium-speed mode | Fast mode: up to 2.5x output speed | Fast mode ~2x output speed |
Coding & Agentic Standing
| Feature | Claude Opus 5 | GPT-5.6 Sol |
|---|---|---|
| Positioning | Anthropic's default for complex agentic coding and enterprise work | OpenAI's flagship for the hardest professional, coding, and research work |
| Agentic / tool use | Step-change over Opus 4.8 on deep-reasoning and agentic work | Strong at command-line and multi-step coding; max/ultra reasoning modes |
| Vendor benchmark suites reported | SWE-bench (Verified / Pro) | SWE-bench Pro, Terminal-Bench, TAU-bench |
| Directly comparable head-to-head score | No shared vendor-published benchmark | No shared vendor-published benchmark |
Access & Openness
| Feature | Claude Opus 5 | GPT-5.6 Sol |
|---|---|---|
| Open weights | ✗ | ✗ |
| Where you can run it | Claude API, Bedrock, Vertex, Foundry; Claude Code on Pro/Max; OpenCode Zen | ChatGPT Plus and above, OpenAI API, Cursor |
| Reasoning control | Thinking on by default; effort low-max | reasoning.effort none-max; higher max/ultra modes |
| Zero-data-retention option | ✓ | Not published |
Speed & Fit
| Feature | Claude Opus 5 | GPT-5.6 Sol |
|---|---|---|
| Speed tier | Frontier; optional fast mode up to 2.5x output tokens/sec | Flagship reasoning tier (Terra/Luna are faster, cheaper siblings) |
| Best-fit workload | Complex agentic coding and enterprise engineering work | Hard coding, research, and command-line agent work |
The Verdict
Choose Claude Opus 5 if...
- ✓You want Anthropic's coding-first flagship with a zero-data-retention option
- ✓You need Bedrock, Vertex, or Microsoft Foundry deployment, or Claude Code on Pro/Max
- ✓You value fast mode for up to 2.5x output speed when latency matters
- ✓You want up to 300K output on the Batch API for very long generations
Choose GPT-5.6 Sol if...
- ✓You want the top GPT-5.6 tier at a lower promo output rate ($20 vs $25 per 1M)
- ✓You live in ChatGPT Plus, the OpenAI API, or Cursor
- ✓You value command-line and multi-step coding strength plus max/ultra reasoning
- ✓You want the option to drop to Terra or Luna for cheaper work in the same family
- ✓Your prompts stay under 272K input tokens, avoiding Sol's long-context surcharge
Frequently Asked Questions
What is the difference between Claude Opus 5 and GPT-5.6 Sol?
Claude Opus 5 is Anthropic's default for complex agentic coding and enterprise work, a step-change over Opus 4.8 released July 24, 2026. GPT-5.6 Sol is the flagship tier of OpenAI's GPT-5.6 family, tuned for the hardest professional, coding, and research work and strong at command-line, multi-step problems.
How much do Claude Opus 5 and GPT-5.6 Sol cost?
Claude Opus 5: $5.00. GPT-5.6 Sol: $4.00 (promo; $5.00 list, through 2026-11-21). See the pricing table above for full plan details.
Should I choose Claude Opus 5 or GPT-5.6 Sol?
Choose Claude Opus 5 if you want Anthropic's coding-first flagship with a zero-data-retention option. Choose GPT-5.6 Sol if you want the top GPT-5.6 tier at a lower promo output rate ($20 vs $25 per 1M).
1DevToolRun whichever model wins — from one workspace
Claude Opus 5 and GPT-5.6 Sol are both closed models you reach through an agent or API. 1DevTool runs Claude Code, Codex, and Gemini CLI side by side in persistent terminals, so you can drive Opus 5 and GPT-5.6 Sol from the same workspace with your own keys or subscriptions — no lock-in to either lab. It adds a built-in HTTP client, 13-engine database client, and embedded browser, all wired into Send-to-AI. One-time $29, no subscription.