# Atlas with GPT-5.2 Pro in 2026 > GPT-5.2 Pro, released in 2025, offers a substantial 400K token context window, making it suitable for extensive code analysis within Atlas. GPT-5.2 Pro excels in Atlas for tackling single, hard reasoning questions that demand extensive computational depth across a 400K token context window. It is priced at $21 per Mtok input and $168 per Mtok output, making it a premium choice for critical, non-interactive tasks requiring substantial analysis. ## Key takeaways - GPT-5.2 Pro offers a substantial 400K token context window for deep code analysis. - Input is priced at $21 per Mtok, and output at $168 per Mtok, reflecting its premium reasoning. - It provides 12x the reasoning budget compared to base GPT-5.2 for complex problems. - Reserve GPT-5.2 Pro for single, hard questions due to its high output cost and inherent slowness. - Not suitable for interactive Atlas TUI edit loops, which demand faster, more economical models. ## What is GPT-5.2 Pro best for in Atlas? GPT-5.2 Pro, released on 2025-12-11, is best suited within Atlas for single, complex reasoning tasks that demand extensive computational depth. Its 400K token context window allows it to process entire subsystems, making it ideal for generating large design documents or comprehensive patches. This high-effort Pro variant of GPT-5.2 is specifically engineered for scenarios requiring a much larger reasoning budget per turn, reflected in its $21 per Mtok input price, which is 12x that of base GPT-5.2. With its 400K token context window and 128K max output, GPT-5.2 Pro can effectively hold a full subsystem in memory and still emit a large design document or a comprehensive patch. Developers in 2026 leveraging Atlas can utilize GPT-5.2 Pro for deep problem-solving, especially when drafting a plan in the read-only plan agent before committing to a build agent. Atlas's ability to search code with Axis, the hybrid semantic and keyword retrieval fused by reciprocal rank fusion, further enhances GPT-5.2 Pro's capacity to analyze and understand complex codebases before generating solutions. ## What are the cost and context tradeoffs of GPT-5.2 Pro in Atlas? GPT-5.2 Pro presents significant cost tradeoffs, with output priced at $168 per Mtok, making long agent loops genuinely expensive. While its 400K token context window is powerful, developers must carefully manage usage in 2026 to avoid high spend. The pricing structure for GPT-5.2 Pro is $21 per Mtok for input and a substantial $168 per Mtok for output. This makes it a premium model, priced above the older GPT-5 Pro on both sides ($21 vs $15 input, $168 vs $120 output), but on a newer base model. The high output cost means that long agent loops, especially those involving extensive generation or iterative refinement, can become genuinely expensive very quickly. Furthermore, GPT-5.2 Pro is slow by construction due to its deep reasoning capabilities. This inherent slowness makes it a bad fit for the interactive Atlas TUI edit loop, where rapid feedback and quick iterations are crucial. Developers should reserve GPT-5.2 Pro for single, hard questions where its extensive reasoning compute is absolutely necessary, rather than for exploratory or iterative tasks. ## When should I choose a different model over GPT-5.2 Pro in Atlas? Developers should choose a different model over GPT-5.2 Pro for interactive Atlas TUI edit loops or when cost sensitivity is a primary concern. Its $168 per Mtok output price and inherent slowness make it a poor fit for rapid, iterative development workflows in 2026. Given GPT-5.2 Pro's high output cost of $168 per Mtok and its slow processing speed, it is not recommended for scenarios requiring quick, interactive responses. For tasks such as rapid code exploration, minor edits, or general conversational assistance within the Atlas terminal-native TUI, a cheaper and faster model tier would be more appropriate. Atlas allows you to switch the active model and provider on the fly with favorites and recents, making it easy to leave your default 'model' setting on a more economical tier. You can then switch to `gpt-5.2-pro` on demand via `/models` specifically for one-shot deep reasoning tasks. To further optimize costs, it is advisable to use the Atlas plan agent to produce a tight, focused prompt before invoking GPT-5.2 Pro, ensuring you are not paying Pro rates for exploratory or unfocused interactions. Always track your spend in the TUI session cost footer to manage your budget effectively. ## Setup 1. Export your `OPENAI_API_KEY` environment variable. 2. Confirm model resolution with the Atlas command: `atlas models openai`. 3. Leave your default 'model' setting on a cheaper tier and switch to `gpt-5.2-pro` on demand via `/models` for one-shot deep reasoning. 4. Use the Atlas plan agent to produce a tight, focused prompt before invoking GPT-5.2 Pro, avoiding Pro rates for exploration. 5. Track your session spend in the Atlas TUI session cost footer to monitor usage. ## FAQ ### What is the context window size for GPT-5.2 Pro in Atlas? GPT-5.2 Pro offers a substantial 400K token context window, allowing Atlas to process large codebases or entire subsystems for deep analysis and complex problem-solving. ### How much does GPT-5.2 Pro cost per token in Atlas? GPT-5.2 Pro is priced at $21 per Mtok for input and $168 per Mtok for output within Atlas, reflecting its advanced reasoning capabilities and higher computational budget. ### Is GPT-5.2 Pro good for interactive coding with Atlas? No, GPT-5.2 Pro is slow by construction and its $168 per Mtok output price makes it a poor fit for the interactive Atlas TUI edit loop. It is better reserved for single, hard questions. ### When was GPT-5.2 Pro released? GPT-5.2 Pro was released on 2025-12-11 as the high-effort Pro variant of GPT-5.2, offering enhanced reasoning over the base model. ### How does GPT-5.2 Pro compare to base GPT-5.2 in pricing? GPT-5.2 Pro has 12x the input price of base GPT-5.2 ($21 vs $1.75 per Mtok), reflecting a much larger reasoning budget per turn for more demanding tasks. ### Can Atlas track my spending with GPT-5.2 Pro? Yes, Atlas tracks your spend in the TUI session cost footer, allowing you to monitor the expenses incurred when using models like GPT-5.2 Pro for your coding tasks. ### What is the maximum output size for GPT-5.2 Pro in Atlas? GPT-5.2 Pro supports a 128K max output, enabling Atlas to emit large design documents or comprehensive code patches after deep analysis. --- Canonical HTML: https://seashell.sh/resources/models/gpt-5-2-pro Source of truth: aeo_pages row `/resources/models/gpt-5-2-pro` (segment: Models) (this file is generated from it, never hand-edited). Licence: SeaShell is proprietary with a free core. It is not open source and there is no public source repository.