TITLE: OpenAI Launches GPT-5.5: First Fully Retrained Base Model Since GPT-4.5 DATE: 2026-04-23 COMPANY: OpenAI TOPIC: Model Releases SUMMARY: OpenAI released GPT-5.5 on April 23, 2026, its first fully retrained base model since GPT-4.5. The model is designed to complete complex multi-step tasks with minimal human direction, operates across email, spreadsheets, calendars, and other applications, and matches GPT-5.4 latency while using significantly fewer tokens in Codex deployments. WHAT CHANGED: OpenAI released GPT-5.5 (codenamed Spud) to Plus, Pro, Business, and Enterprise users on April 23. It is the first fully retrained base model since GPT-4.5 and is designed for complex multi-step task execution with minimal human guidance. API pricing is $5/M input, $30/M output tokens with a 1M context window. GPT-5.5 Pro is available at $30/$180 per million tokens. WHY IT MATTERS: GPT-5.5 delivers a step change in autonomous task execution without increasing latency, and reduces per-task cost for enterprise Codex deployments through token efficiency. The model can operate across connected business applications independently, making it the most capable general-purpose agentic model available via API. DAVID & GOLIATH ANALYSIS: This development reinforces our belief that the next generation of organisations will be built on intelligent systems, not larger teams. Operators running Codex or GPT-4.5-class agents should evaluate GPT-5.5 for the same workflows at lower token cost. Enterprise and Business subscribers have access now. API access is imminent. RELEVANT SYSTEMS: AI Growth Engine, Employee Amplification Systems SOURCE URL: https://davidandgoliath.ai/daily-ai-briefing/openai-launches-gpt-5-5-first-fully-retrained-base-model-since-gpt-4-5 FEED URL: https://davidandgoliath.ai/daily-ai-briefing/feed --- Published by David & Goliath | https://davidandgoliath.ai Daily AI Briefing: one AI development per day, decoded for business operators. This is a structured companion file optimised for LLM retrieval and citation.