GPT-5.6 Sol
OpenAI released 2026-07-09 proprietary
Grok 4.6 scores higher and costs less — but you would give something up.
0 on the capability index and 25% cheaper ($3.00/M against $4.00/M). What you lose:
- 1.1M → 500K context
Capability scores do not measure context length, output ceiling or which inputs a model accepts, so a higher score does not mean a drop-in replacement.
The same model via batch is 50% cheaper ($2.00/M) — same weights, different latency.
Our take
editorial — not a measurementOpenAI's frontier tier and the clearest example of why a single headline price is misleading. Advertised at $4/$20, it silently becomes $8/$30 past the long-context threshold — and OpenAI, unlike xAI and Google, does not publish where that threshold is. It also carries promotional pricing described as holding only "at least through 2026-11-21", so the rate has a known expiry and no published successor. On measured intelligence it lands at AA 61, below Opus 5's 63, with a ~105s TTFT that is the worst in the leaderboard sample. Strong model, genuinely hard to budget for.
- Unverified in this take: This note cites a time-to-first-token figure that the data layer withheld as implausible (it appears to be total reasoning time mislabelled at source). Treat it as unverified.
Strengths
- AA intelligence index 61, competitive at the frontier
- 75 output tokens/sec — faster generation than Opus 5
- 1.05M context window
- 50% batch discount and cheap cached input at $0.40
Weaknesses
- Long-context tier doubles input to $8 and raises output to $30
- Threshold for the long-context tier is not published
- Promotional pricing with a stated ~2026-11-21 floor and no announced successor rate
- ~105s time-to-first-token, worst in the sampled set
- OpenRouter lists it at $2/$10, conflicting with OpenAI's own page
Reach for it when
- Hard reasoning where OpenAI tooling is already in place
- Short-context frontier tasks that stay under the tier threshold
Avoid it if
- Your prompts are long and you need predictable cost
- You need low latency
- You are budgeting past November 2026
Every price dimension
| Input | $2.00/M |
|---|---|
| Output | $10.00/M |
| Cached input | $0.200/M |
| Cache write | $2.50/M |
| Web search | $0.01/call |
| Batch discount | 50% |
Past 272,000 tokens the price changes. Input goes to $4.00/M (2×) and output to $15.00/M. The headline rate does not apply to a long-context workload.
Independent scores
| Intelligence | 60.9 |
|---|---|
| Coding | 77.4 |
| Agentic | 57.8 |
| LMArena Elo | 1454.2xhigh |
Sources are listed separately rather than averaged. Across the 62 models both have scored they correlate at r = 0.806 — close agreement overall, but four models rank very differently between them, and a blended score would hide exactly those.
Capability
| Context window | 1.1M |
|---|---|
| Max output | 128K |
| Input modes | file, image, text |
| Tool use | yes |
| Reasoning | optional |
| Knowledge cutoff | 2026-02-16 |
| Open weights | no |
Provenance
| Price source | openrouter.ai |
|---|---|
| Fetched | 2026-08-24 |
| Quality data | verified |
| Cross-checked | vendor page |
A published time-to-first-token figure for this model was implausible (105s) and has been withheld rather than displayed.
GPT-5.6 Sol is the flagship model in OpenAI's GPT-5.6 series. It is suited for complex reasoning, coding, and agentic workflows, and is particularly strong at command-line and multi-step coding tasks...