GPT 5.5

2026-04-23 · Source: AINews · Field: Technology & Digital — Artificial Intelligence & Machine Learning, Software Development & Engineering, Cloud Computing & IT Infrastructure · Depth: Expert, extended

Summary

OpenAI has launched GPT-5.5 as its new flagship frontier model, immediately available in ChatGPT and Codex for Plus, Pro, Business, and Enterprise users. API access is delayed pending additional safety requirements. The model is priced at $5/$30 per million input/output tokens for GPT-5.5 and $30/$180 for GPT-5.5 Pro, noted as double GPT-5.4's per-token cost, though OpenAI claims improved token efficiency. GPT-5.5 is positioned for "real work and powering agents," excelling in coding, computer use, knowledge work, and multi-step execution with tool use and self-checking. Codex also received significant upgrades, including browser control, file/document handling, and OS-wide dictation. Benchmarks show strong performance, with GPT-5.5 scoring 82.7% on Terminal-Bench 2.0 and 85.0% on ARC-AGI-2, though some independent evaluations highlight an 86% hallucination rate on AA-Omniscience. The launch also saw significant activity around Google DeepMind's "Vision Banana" for image understanding and generation, new open models like Kimi K2.6 and Qwen3.6-27B, and advancements in training/inference systems like Deepseek's TileKernels.

Key takeaway

For AI Engineers and CTOs evaluating frontier models for agentic applications, GPT-5.5 represents a significant shift towards practical, long-horizon task execution. While its per-token cost is higher, its reported token efficiency and enhanced capabilities in coding and computer use could lead to lower effective task costs and reduced micromanagement. You should prioritize testing GPT-5.5's performance on your specific agentic workflows and consider its integration with Codex for broader enterprise computer-use cases, while also noting its reported hallucination rate on certain benchmarks.

Key insights

GPT-5.5 advances agentic AI, emphasizing practical, long-horizon task execution and token efficiency over raw benchmark gains.

Principles

• Agentic capabilities are critical for "real work."
• Token efficiency can offset higher per-token costs.
• Harness design significantly impacts agent quality.

Method

OpenAI's GPT-5.5 and Codex integrate browser control, file handling, and OS-wide dictation for multi-step, lower-micromanagement agentic workflows.

In practice

• Explore GPT-5.5 for complex coding and long-running tasks.
• Evaluate models based on intelligence per dollar/token.
• Consider Qwen3.6-27B for local, VRAM-constrained coding.

Topics

• GPT-5.5
• AI Agents
• OpenAI Codex
• LLM Benchmarking
• Inference Economics

Code references

• ggml-org/llama.cpp
• deepseek-ai/DeepEP
• deepseek-ai/TileKernels
• fagenorn/handcrafted-persona-engine
• AtomicBot-ai/Atomic-Chat

Best for: AI Engineer, CTO, VP of Engineering/Data, AI Scientist, Machine Learning Engineer, Director of AI/ML

Related on AIssential

• OpenAI's GPT-5.5 is here, and it's no potato: narrowly beats Anthropic's Claude Mythos Preview on Terminal-Bench 2.0 — GPT-5.5 redefines AI agency, excelling in complex, multi-part tasks with less human guidance.
• GPT-5.5 is HERE! — GPT 5.5 offers enhanced intelligence and token efficiency, particularly for coding and research, at a lower effective cost.
• What I Learned Testing GPT-5.5 — GPT 5.5 reclaims OpenAI's leadership in AI, excelling in "real work" tasks and agentic workflows.
• TAI #202: GPT-5.5 Moves Codex Into Real Work — Frontier AI models are evolving into integrated work systems, emphasizing tools, memory, and permissions over raw model capability.
• GPT 5.5 LET'S GOOOOOOOO! — GPT-5.5 enhances agentic capabilities, coding performance, and multi-step task execution, signaling a shift towards more autonomous AI.
• I Tried The New GPT 5.5 And I’m Never Going Back — GPT 5.5 excels at complex task execution and agentic workflows, moving beyond simple query responses.

Counsel's verdict on this

AIssential's Counsel cites this article in its editorial verdict on the decision it informs:

• Migrate to GPT-5.5 now, or stay on 5.4? — GPT-5.5 benchmarks higher for coding agents, but its 2× token-price hit and 40% token reduction mean adaptive routing is key to limiting net cost increases to 20%.

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Editorial summary, takeaway, and curation by AIssential. Original article published by AINews.