GPT-6.1 Sol: Specs, Pricing, Context Window and Availability Facts

GPT-6.1 Sol is a proprietary large language model from OpenAI, released on 29 September 2026, which OpenAI's models page describes as "near-Astra performance for complex work at a lower cost". This profile collects the published facts about it: API identifier, context window, output limit, knowledge cutoff, prices for every service tier, tools, cloud availability, safety ratings from its system card and deprecation status. It also records where GPT-6.1 Sol is named as the replacement for retiring OpenAI models. It is written for developers, architects, buyers and governance teams. Every fact comes from OpenAI's own documentation and system card, and where OpenAI publishes nothing on a point, the page says so.

Last checked: 2026-11-15.

This is an independent reference page from NHI Mgmt Group based on public provider documentation; it is not sponsored or endorsed by any provider. It uses OpenAI's public documentation as of November 2026. Model details change, so confirm against OpenAI's current documentation.

Key takeaways

• Released 29 September 2026. The OpenAI API changelog records GPT-6.1 Sol (API ID gpt-6.1-sol) "for complex coding and professional work at a lower cost than GPT-6 Astra".
• 1.05M tokens in, 128K out. The model page lists a 1,050,000-token context window, 128,000 maximum output tokens and a knowledge cutoff of 30 April 2026.
• $2 input and $10 output per million tokens. Standard pricing, with cached input at $0.10, Batch and Flex at 50% of Standard, Fast mode at 2x and Ultrafast at 6x.
• Critical for cybersecurity under the Preparedness Framework. OpenAI's system card addendum treats GPT-6.1 Sol as Critical in cybersecurity and High for biological and chemical capability.
• Named replacement for GPT-5 and o3. OpenAI's deprecations page points gpt-5, gpt-5-pro, o3 and o3-pro, all shutting down on 11 December 2026, to gpt-6.1-sol; GPT-6.1 Sol itself has no deprecation date.

What is GPT-6.1 Sol?

GPT-6.1 Sol is the Sol tier of OpenAI's GPT-6 generation. OpenAI's 2026 naming uses four tiers: Astra, Sol, Terra and Luna. Sol sits below Astra, and the model page lists complex coding, computer use and professional work as recommended uses. It is a reasoning model whose depth is set with the reasoning effort parameter, with medium as the default.

It is the second Sol model in the GPT-6 generation. GPT-6 Sol (gpt-6-sol) was released on 22 September 2026, and its model page now says "See GPT-6.1 Sol for the newer Sol model". GPT-6.1 Sol accepts text and image input and returns text. It is closed weight and proprietary, and OpenAI does not state a parameter count. For the full OpenAI line-up, see OpenAI Models.

Key facts at a glance

As of 2026-11-15. Source: OpenAI model page for gpt-6.1-sol, API changelog and system card addendum.

Release and version history

As of 2026-11-15. Dates from the OpenAI API changelog, model pages and deprecations page.

The model page lists one snapshot, gpt-6.1-sol, with no dated variants. The earlier GPT-6 Sol remains callable with its own pricing and an earlier knowledge cutoff of 20 April 2026.

How much does GPT-6.1 Sol cost?

As of 2026-11-15. USD per million text tokens. Source: OpenAI pricing page and the gpt-6.1-sol model page.

• Long prompts: prompts over 272K input tokens are charged at 2x input and cache rates and 1.5x output, for the whole request (model page).
• Cached input: $0.10 is 5% of the uncached input rate; a 30-minute cache write is 1.25x the uncached rate.
• Regional processing: the model page states a 10% premium where regional processing is available; the pricing page states the same uplift on FedRAMP endpoints.
• Subscriptions: the model page says Codex and ChatGPT Work default to a 500K context window, and subscription usage has no long-context surcharge.
• Tool fees: web search is $10.00 per 1,000 calls plus search content tokens at model rates; other tool fees are listed on the pricing page.

Worked example at Standard rates: a request with 100,000 input tokens and 10,000 output tokens costs $0.20 for input plus $0.10 for output, $0.30 in total, before any tool fees.

Context window and output limits

The context window is 1,050,000 tokens and the maximum output is 128,000 tokens per response. Requests above 272K input tokens are billed at higher rates, and Codex and ChatGPT Work use a 500K default context, so the practical limit depends on the channel.

Modalities and tools

GPT-6.1 Sol accepts text and images and returns text. Audio and video are not supported on this model, and it does not output images itself.

• Features: streaming, function calling and Structured Outputs are supported; fine-tuning is not.
• Responses API tools: web search, file search, image generation, code interpreter, hosted shell, apply patch, skills, computer use, MCP and tool search. The model page states that tool calling requires the Responses API.
• Reasoning effort: low, medium (default), high, xhigh and max. GPT-6.1 Sol does not support none; OpenAI's GPT-6 guide says to use low when moving from gpt-6-sol with none.
• Pro mode: the deprecations page names gpt-6.1-sol with reasoning.mode set to pro as the replacement for gpt-5-pro and o3-pro.
• Multi-agent and persisted reasoning: the GPT-6 guide says GPT-6.1 Sol supports the Responses Multi-agent beta for delegating work to subagents, and reasoning.context set to all_turns reuses compatible reasoning from earlier turns.
• Unsupported sampling parameters: temperature, top_p and top_logprobs must be removed, and logprobs in Chat Completions.

Subagents, hosted shell, computer use and MCP extend what the model can reach, so each tool needs scoped credentials and approval rules. See the Securing OpenAI Agents SDK and Responses API Guide.

Where is GPT-6.1 Sol available?

As of 2026-11-15. Source: gpt-6.1-sol model page and GPT-6 guide.

The GPT-6 guide states that Ultrafast mode for GPT-6.1 Sol supports US and EU data residency and global processing. Region lists for other options are in OpenAI's separate data residency guide.

Access restrictions

GPT-6.1 Sol is not a restricted-access model in the API: it is a flagship model with published rate limits for paid tiers, and it is not supported on the Free tier. The system card addendum states that cyber access is phased through Trusted Access for Cyber (OpenAI Daybreak), with expanded defensive access alongside stronger safeguards, and that GPT-6.1 Sol uses the same safeguards stack as GPT-6 Astra. OpenAI's specialised cyber models, gpt-6-cyber and gpt-5.6-cyber, sit separately under Daybreak.

Benchmarks (provider-reported, dated)

As of 2026-11-15. All figures are provider-reported, from the GPT-6.1 Sol system card addendum published 29 September 2026. Independent leaderboard results are not included because none were checked against their own published pages for this profile.

For deception rates and flag counts, lower is better; for the other scores, higher is better. Cyber capability scores are reported to explain the Preparedness rating, not as product features.

Model card and system card

OpenAI published the GPT-6.1 Sol system card on its Deployment Safety Hub on 29 September 2026, as an addendum to the GPT-6 Astra system card. What it states:

• Preparedness ratings: "we are treating GPT-6.1 Sol as Critical in cybersecurity and High for Biological and Chemical capability"; it is below the High threshold in AI self-improvement.
• Biology: the Critical threshold was not reached; reported scores include Tacit Knowledge and Troubleshooting 88.50% and ProtocolQA Open-Ended 40.74%.
• Cyber: ExploitBench 99.7%, which the card says may be inflated by contamination, and 21.5% arbitrary code execution success on an internal ExploitBench port versus 31.5% for GPT-6 Astra; the Production Chat cybersecurity refusal rate is 0.987.
• Safeguards: the same safeguards stack as GPT-6 Astra, addressing malicious use and unauthorised, misaligned model activity, judged sufficient for public launch.
• Monitorability: chain-of-thought controllability (750 to 1,250 tokens) was 44.8% versus 60.9% for GPT-6 Astra.

OpenAI positions the addendum within its Preparedness Framework. For how labs structure these ratings, see the Frontier AI Model Risk Frameworks Guide.

Data handling

OpenAI's API data controls page applies to GPT-6.1 Sol as to other API models. There is no model-specific data policy for GPT-6.1 Sol on the pages checked.

• Training use: data sent to the OpenAI API is not used to train or improve OpenAI models unless the customer explicitly opts in.
• Abuse monitoring logs: kept for up to 30 days by default, unless longer retention is legally required or needed to protect the services.
• Zero Data Retention and Modified Abuse Monitoring: available only with prior OpenAI approval; ZDR forces store to false on Responses and Chat Completions. OpenAI states it may make certain models ineligible for these controls for specific customers with notice.
• Application state: Responses API state is kept for at least 30 days by default when store is true; prompt cache data for up to 24 hours.
• Persisted reasoning: reasoning.context set to all_turns reuses earlier reasoning, so review it against your retention settings.

API keys and service accounts that call GPT-6.1 Sol are non-human identities with direct spend and data exposure. See the OpenAI API Keys Security Guide and OpenAI Platform Organisation and Project Security Guide.

Deprecation status

As of 15 November 2026, OpenAI's deprecations page lists no notice date, shutdown date or replacement for gpt-6.1-sol. It is the named replacement for these retiring models:

The gpt-5.1 and gpt-5.3-codex retirements on 1 April 2027 point to gpt-6-sol instead. Monitor the deprecations page and changelog rather than relying on this snapshot.

How GPT-6.1 Sol differs from other models in its family

As of 2026-11-15. Source: OpenAI models page and per-model pages. Models listed by release date.

All three share the 1,050,000-token context and 128,000-token output limit. Compared with GPT-6 Sol, GPT-6.1 Sol has the same Standard input and output price, cheaper cached input ($0.10 against $0.20), a later knowledge cutoff and no none effort level. Compared with GPT-6 Astra, it costs one fifth as much per token at Standard rates and scores lower on the cyber evaluations reported in its system card. GPT-6.1 Terra and GPT-6 Luna are lower-cost tiers. See GPT-6 Astra vs Sol vs Luna vs Terra and the GPT-6 Astra profile.

Practitioner checklist

• Inventory every call to gpt-5, gpt-5-pro, o3 and o3-pro and migrate to gpt-6.1-sol before 11 December 2026.
• For Pro workloads, set reasoning.mode to pro on gpt-6.1-sol and compare cost and latency against the old model.
• Replace none or minimal reasoning effort with low, and remove temperature, top_p and logprobs parameters.
• Move tool calling to the Responses API; GPT-6.1 Sol requires it.
• Model cost with the 272K threshold, cache hit rates and reasoning effort, and set per-project budgets before enabling Fast or Ultrafast.
• Scope subagents, hosted shell, computer use and MCP tools to least privilege, with approval for destructive actions.
• Confirm ZDR or Modified Abuse Monitoring approval before sending regulated data, and check persisted reasoning settings.
• Store API keys in a secrets manager, separate projects by environment and rotate keys on staff changes.
• Watch the deprecations page and changelog monthly for changes to gpt-6.1-sol.

Standards and references

• OpenAI: GPT-6.1 Sol model page (accessed 2026-11-15)
• OpenAI Deployment Safety Hub: GPT-6.1 Sol System Card (accessed 2026-11-15)
• OpenAI: API pricing (accessed 2026-11-15)
• OpenAI: API changelog (accessed 2026-11-15)
• OpenAI: Deprecations (accessed 2026-11-15)
• OpenAI: Using GPT-6 models guide (accessed 2026-11-15)
• OpenAI: GPT-6 Sol model page (accessed 2026-11-15)
• OpenAI: Data controls in the OpenAI platform (accessed 2026-11-15)

Related NHI Mgmt Group resources: OpenAI Models, GPT-6 Astra vs Sol vs Luna vs Terra, GPT-6 Astra, OpenAI Codex Security Guide, How to audit OpenAI and Anthropic organisation API keys.