# Subconscious vs OpenAI

> Subconscious is built for the agent traces where OpenAI gets expensive. Past 272K tokens OpenAI bills input at 2x, while Subconscious bills only the tokens it processes after compression.

Canonical: https://www.subconscious.dev/compare/subconscious-vs-openai · By The Subconscious Team · Updated September 30, 2026

## How they compare

This matchup splits on trace length. OpenAI is a closed lab with GPT-6 Astra at the top and a 1.05M context window across its lineup, but prompts over 272K tokens bill input at 2x and output at 1.5x. A coding agent that has been running for an hour crosses that line early and stays there. Subconscious is built for exactly that stretch. It prunes the KV cache instead of rereading the full context on each step, delivers a 5M+ effective context window and 2x faster task completion, and bills only the tokens it processes after compression. A request that sends 1M tokens might bill for 200K on Subconscious, while OpenAI bills the full 1M at its long-context rate.

OpenAI wins on breadth and on closed frontier quality. GPT-6 Astra posts frontier results on computer use and coding, the Responses API bundles hosted web search, file search and computer use, and its SDK ecosystem is the largest in the market. Short chat turns and high-volume extraction on Luna at $0.20 in are well served by OpenAI. The practical split: keep OpenAI for customer-facing assistants and tool-heavy short requests, and route long-running coding and research agents to Subconscious, which speaks the OpenAI SDK format and plugs into Codex.

## What each one does

### Subconscious

Subconscious is an MIT CSAIL spinout in Kendall Square that builds inference for long-horizon agents, the workloads where a single trace runs past 200K tokens and often into the millions. Its runtime drops in as a replacement for vLLM or SGLang. Instead of rereading an ever-growing context on every step, it prunes the KV cache and preserves suffix state, and Subconscious co-designs the runtime with post-trained model variants it calls Marathon. Against open models on standard inference, Subconscious delivers 2x faster task completion, delivers a 5M+ effective context window, cuts cost 50% and up to 80%, and scores neutral to 10% better on agentic benchmarks.

### OpenAI

OpenAI runs the most widely adopted closed-model API. Its September 2026 lineup has GPT-6 Astra at the top for computer use, coding and long agentic runs, priced at $10 in and $50 out per million tokens. Below it sits the GPT-5.6 family: Sol for hard professional work, Terra as the balanced default, and Luna for high-volume jobs at $0.20 in and $1.20 out. All of them carry a 1.05M token context window with up to 128K output.

## Which is best, and when

### Choose Subconscious for

- Coding agents whose prompts run past OpenAI's 272K surcharge line
- Hour-long traces billed on processed tokens, not tokens sent
- Teams that want open models with no prompt logging

### Choose OpenAI for

- Closed frontier quality on computer use and coding with GPT-6 Astra
- Short assistant turns with hosted web search and file search
- High-volume classification on Luna at $0.20 in

## At a glance

| Attribute | Subconscious | OpenAI |
|---|---|---|
| Model access | Open weights | Closed, plus open gpt-oss |
| Flagship models | GLM 5.3, DeepSeek V4.1 Flash | GPT-6 Astra, GPT-5.6 Sol, Terra, Luna |
| Speed | 2x faster task completion | Fast mode: up to 2.5x at 2x price |
| Price | 50–80% lower cost; billed on processed tokens | $0.20–$10 in, $1.20–$50 out per 1M |
| Customization | Marathon post-trained variants | N/A |
| Deployment | Managed API, dedicated, on-prem | API, Azure OpenAI, Bedrock |
| Long context | 5M+ effective context | 1.05M; 2x input past 272K |

## FAQ

### What is the difference between Subconscious and OpenAI?

Subconscious is built for the agent traces where OpenAI gets expensive. Past 272K tokens OpenAI bills input at 2x, while Subconscious bills only the tokens it processes after compression.

### When should I choose Subconscious over OpenAI?

Coding agents whose prompts run past OpenAI's 272K surcharge line; Hour-long traces billed on processed tokens, not tokens sent; Teams that want open models with no prompt logging.

### When should I choose OpenAI over Subconscious?

Closed frontier quality on computer use and coding with GPT-6 Astra; Short assistant turns with hosted web search and file search; High-volume classification on Luna at $0.20 in.

### Is Subconscious or OpenAI cheaper?

Subconscious: 50–80% lower cost; billed on processed tokens. OpenAI: $0.20–$10 in, $1.20–$50 out per 1M. The cheaper choice depends on the model and workload.

### Which has more context, Subconscious or OpenAI?

Subconscious: 5M+ effective context. OpenAI: 1.05M; 2x input past 272K.

## Try Subconscious

Subconscious speaks the OpenAI and Anthropic API formats. Base URL: https://api.subconscious.dev/v1. Docs: https://docs.subconscious.dev. Get an API key: https://platform.subconscious.dev/signin. Agent guide: https://www.subconscious.dev/agents.md.

Full profiles: [Subconscious](https://www.subconscious.dev/providers/subconscious.md), [OpenAI](https://www.subconscious.dev/providers/openai.md).