As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/m/gpt-6-1-sol/

# GPT-6.1 Sol

OpenAI, GPT-6 family. Status: current. Type: reasoning model. Released: 2026-09-29. Training cutoff: 2026-04.

## How to call it

| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| OpenAI API | `gpt-6.1-sol` | https://api.openai.com/v1/responses | https://developers.openai.com/api/docs/models/gpt-6.1-sol |
| OpenRouter | `openai/gpt-6.1-sol` |  | https://openrouter.ai/openai/gpt-6.1-sol |
| GitHub Copilot |  |  | https://github.blog/changelog/2026-09-29-gpt-6-1-sol-in-github-copilot |
| AWS Bedrock (GA late Sept 2026; Ultrafast mode added Oct 9; reasoning summaries via Responses API) |  |  | https://aws.amazon.com/about-aws/whats-new/2026/09/openai-gpt-6-1-sol-on-amazon-bedrock/ |
| Web app |  |  | https://chatgpt.com |

## Pricing

- Input: $2 per 1M tokens
- Cached input: $0.10 per 1M tokens
- Output: $10 per 1M tokens
- Cache write: $2.50 per 1M tokens
- Unit as published: per 1M tokens (USD), standard tier
- Note: prompts >272K input tokens billed at 2x input/cache and 1.5x output; Fast mode 2x; Batch/Flex 50% off; Ultrafast (since Oct 8 2026) 6x standard, i.e. $12 input / $0.60 cached / $15 cache write / $60 output per 1M short-context ($24/$1.20/$30/$90 long-context)
- Source: https://developers.openai.com/api/docs/models/gpt-6.1-sol
- Last checked: 2026-10-11

## Specs

- Input: text, image
- Output: text
- Context window: 1,050,000 tokens
- Max output: 128,000 tokens
- Open weights: no
- Licence: proprietary

## What it has not seen

- Published training cutoff: 2026-04 (April 2026).
- AI events after it on Post-Cutoff: 1,863 (426 major, 83 historic), as of 2026-11-13.
- Already missing at launch: 570.
- Briefings of the news since April 2026: https://postcutoff.com/briefings/cutoff-2026-04-s.md (short), https://postcutoff.com/briefings/cutoff-2026-04-m.md (medium), https://postcutoff.com/briefings/cutoff-2026-04.md (full).
- Its card, with five things it has never heard of: https://postcutoff.com/you/gpt-6-1-sol/

## What stands out

- Near-Astra quality at one-fifth the price: OpenAI says it nearly matches GPT-6 Astra on agentic coding (DeepSWE v1.1), computer use (OSWorld 2.0, within 2.1 pts at ~1/7 cost/task) and professional work at $2/$10 vs Astra's $10/$50. Source: https://openai.com/index/introducing-gpt-6-1-sol/
- Near-Astra ARC-AGI-3 score at lower cost (found after launch): ARC Prize verified (Sept 30, 2026): ARC-AGI-3 96.4% at $4.4K with the provider-adapter harness (52.7% with the standard harness) vs GPT-6 Astra's 99.9%, at 77% lower cost; ARC-AGI-2 94.2% at $0.25/task. Source: https://x.com/arcprize/status/2105391846067249649
- 95% cached-input discount: Cached input costs $0.10 per 1M tokens (5% of the input rate), half of GPT-6 Sol's cached price. Source: https://developers.openai.com/api/docs/models/gpt-6.1-sol
- Improved alignment vs GPT-6 Sol: Failed to disclose a broken search tool in 2.1% of adversarial tests (GPT-6 Sol 4.9%, Astra 1.5%); no observed attempts to bypass the automated safety reviewer. Source: https://cdn.openai.com/pdf/38e3efcf-545e-44cd-99ec-2b7eb395f4cc/oai_GPT_6_1_Sol.pdf
- Full hosted tool suite: Responses API tools: web/file search, image generation, code interpreter, hosted shell, apply patch, skills, computer use, MCP, tool search. Source: https://developers.openai.com/api/docs/models/gpt-6.1-sol
- Multi-agent in the Responses API (beta): The model can spin up and coordinate parallel subagents inside one Responses API request and synthesize their results; enable with the beta header OpenAI-Beta: responses_multi_agent=v1 (also available for all GPT-5.6 models). OpenAI's Oct 2 2026 GPT-6 model guide names GPT-6.1 Sol as the family member that supports delegation. Source: https://developers.openai.com/api/docs/guides/responses-multi-agent
- Ultrafast service tier (found after launch): Since Oct 8 2026, service_tier "ultrafast" in the Responses API (all API users, separate rate limits, WebSockets recommended) at 6x standard price; also in Codex and ChatGPT Work for Pro $500 and eligible Enterprise/Edu plans. OpenAI promised up to 8x faster token generation in Codex and up to 6x in the API. Source: https://developers.openai.com/api/docs/changelog

## Notes

Successor to GPT-6 Sol, released one week later at DevDay 2026. reasoning.effort low/medium(default)/high/xhigh/max (no none/minimal). Max input 922K tokens. Chat Completions supported without tool calling. US/EU data residency (Fast mode unavailable with EU residency). In ChatGPT Work and Codex for Plus and above; not yet in Chat as of launch. Ultrafast version promised 'in the coming days' at launch; it shipped on Oct 8 2026 (API changelog, Codex changelog), see 2026-10-08-gpt-6-1-sol-ultrafast. Since Oct 7 2026, an October update of GPT-6 Sol (not 6.1) powers the ChatGPT Chat tab for paid tiers, see 2026-10-07-gpt-6-chatgpt-intelligent-ui. OpenRouter also lists openai/gpt-6.1-sol-pro.

OpenAI's default mid-tier model for coding agents, computer use and document work as of Sept 29, 2026.

```bash
curl https://api.openai.com/v1/responses \
 -H "Authorization: Bearer $OPENAI_API_KEY" -H "Content-Type: application/json" \
 -d '{"model":"gpt-6.1-sol","reasoning":{"effort":"medium"},"input":"Hello"}'
```

Rate limits (standard): Tier 1 500 RPM / 500K TPM … Tier 5 15,000 RPM / 40M TPM.

Sources:
- https://openai.com/index/introducing-gpt-6-1-sol/
- https://developers.openai.com/api/docs/models/gpt-6.1-sol
- https://developers.openai.com/api/docs/pricing
- https://github.blog/changelog/2026-09-29-gpt-6-1-sol-in-github-copilot
- https://openai.com/index/practical-guide-building-gpt-6 (GPT-6 family model guide, Oct 2 2026)
- https://developers.openai.com/api/docs/guides/responses-multi-agent

Model page: https://postcutoff.com/m/gpt-6-1-sol/