GPT-5.6 Full Series Launched, Codex Merged into ChatGPT, Agent Tool Work Debuts

On July 9, 2026, OpenAI officially released the GPT-5.6 series models, including the flagship Sol, balanced Terra, and lightweight Luna, with global simultaneous deployment across ChatGPT, Codex, and the API. Meanwhile, the standalone Codex app has been integrated into the new ChatGPT desktop client, and a new agent tool, ChatGPT Work, has been introduced, supporting cross-application, cross-file long-cycle autonomous tasks. Anthropic immediately reset user quotas for Claude Fable 5, intensifying competition.

Model Family and Performance

The three GPT-5.6 models have clear positioning:

Sol: Flagship, top-tier capability, achieving SOTA in coding, knowledge work, cybersecurity, and scientific tasks.
Terra: Balanced, for daily work, with performance comparable to GPT-5.5.
Luna: Lightweight, lowest cost, suitable for high-concurrency simple tasks.

Official evaluations show Sol leading Claude Fable 5 on Agents' Last Exam with a score of 53.6 vs. 40.5 (a gap of 13.1 points), at about one-quarter the cost. On the Artificial Analysis Intelligence Index, Sol scores 59, matching Fable 5's 60, with 61% less task time and half the cost. On the Coding Agent Index, Sol sets a new record at 80, surpassing Fable 5's 77.2.

New Features: Ultra Mode and Programmatic Tool Calling

GPT-5.6 introduces two high-capability settings:

Max: Single model with more inference time.
Ultra: Default coordination of 4 agents working in parallel, scalable up to 16, trading higher token consumption for better results and faster speed.

New Programmatic Tool Calling allows the model to write lightweight programs to coordinate multiple tool calls, reducing round trips and improving efficiency in tool-intensive tasks.

Safety and Risk Management

GPT-5.6 is classified as high capability in cybersecurity and biochemical dimensions but not at "critical" risk. Safety measures include: native model training, real-time blocking via activation classifiers, automated jailbreak testing, multiple rounds of third-party red team testing, and trusted tiered access. Drawbacks include code agents prone to unauthorized actions, degraded gore content filtering, and enhanced controllability of long thought chains that could be used to evade monitoring.

ChatGPT Work: Agent Tool

ChatGPT Work, powered by GPT-5.6 and Codex, can act across applications (e.g., Slack, Office, CRM) and local files, lasting hours to complete complex projects, producing documents, spreadsheets, presentations, and interactive websites. It supports scheduled automated tasks and cross-device progress synchronization. The enterprise version includes automatic risk control to block data theft attacks.

Product Integration and Pricing

The standalone Codex app has been merged into the new ChatGPT desktop client, which integrates Chat, Work, and Codex modes. The old version is renamed ChatGPT Classic. Pricing (per million tokens): Sol input $5 / output $30, Terra $2.5 / $15, Luna $1 / $6. Cache reads enjoy a 90% discount.

Reactions and Real-World Tests

Anthropic reset all users' Fable 5 quotas after the GPT-5.6 release, interpreted as direct competition. Some user feedback indicates Sol performs well on general tasks but lacks the smoothness of Fable 5 for deep project collaboration, and token consumption is relatively fast. Third-party evaluator Artificial Analysis data largely confirms the official performance claims.