A pelican for GPT-5.5 via the semi-official Codex backdoor API
infonewsLLM-Specific
security
Source: Simon Willison's WeblogApril 23, 2026
Summary
GPT-5.5 is a new AI model from OpenAI that is now available through Codex (a code-focused AI tool) and ChatGPT subscriptions, though the standard API is not yet available. The author created a tool called llm-openai-via-codex that lets users access GPT-5.5 through their existing Codex subscription by reverse-engineering how authentication tokens work, rather than waiting for the official API release.
Classification
Attack SophisticationModerate
AI Component TargetedAPI
Affected Vendors
OpenAI
Related Issues
Monthly digest — independent AI security research
Original source: https://simonwillison.net/2026/Apr/23/gpt-5-5/#atom-everything
First tracked: April 23, 2026 at 08:00 PM
Classified by LLM (prompt v3) · confidence: 75%