Summary

GPT‑5.5 is a production model optimized for complex, real‑world tasks — coding, research, document and spreadsheet generation, and multi‑tool workflows. It arrives with improved task understanding, more effective tool use, and stronger self‑checking. OpenAI ran a full predeployment evaluation suite and Preparedness Framework, including targeted red‑teaming for advanced cybersecurity and biological capabilities, and incorporated feedback from ~200 early‑access partners. Evaluations were primarily offline; GPT‑5.5 Pro (same base model with parallel test‑time compute) is treated separately where that setting could change risk or safeguards.

Key Points

• Capabilities: better early task understanding, reduced need for user guidance, improved tool integration, and iterative self‑checking.
• Safety & testing: full predeployment evaluations, Preparedness Framework application, and targeted red‑teaming for cyber and bio risks.
• Early feedback: nearly 200 early‑access partners contributed real‑world usage feedback prior to release.
• GPT‑5.5 Pro: same underlying model but a parallel test‑time compute setting; evaluated separately when relevant to risk or safeguards.
• Evaluation context: unless otherwise noted, results in the system card come from offline evaluations.

Practical guidance for engineers

• Read the full system card before deployment to understand evaluated risks and mitigations.
• Treat GPT‑5.5 and GPT‑5.5 Pro as the same model functionally, but run additional risk-sensitive tests on Pro if you use parallel compute settings.
• Apply standard safety controls (access restrictions, monitoring, red‑team tests) and leverage the published red‑teaming learnings for cyber/bio risk scenarios.
• Validate tool integrations and iterative workflows in your environment, and include self‑check prompts or verification steps where accuracy is critical.