Every published Top AI Stories item tagged with GPT-5.5, newest first.
Free and Go users move to GPT-5.6 Luna as their default, get unlimited text conversations, and gain a Think button that spends more reasoning on hard questions. OpenAI says Luna makes 62 percent fewer factual errors than the GPT-5.5 Instant model it replaces, measured on its own evaluations. Separate caps still apply to files, images, voice and image generation, and the rollout runs across this week and next. Paying subscribers get an updated GPT-5.6 Sol at the same time, on a service now serving roughly one billion weekly users.
OpenAI is moving GPT-5.6 toward broad release, with reports pointing to a mid-July general availability after a government-gated preview limited to about 20 partner organizations. An OpenAI engineer indicated the top 'Sol Ultra' tier — a mode that coordinates subagents to tackle complex work — is coming to Codex, the company's AI coding agent. GPT-5.6 splits into three durable tiers, named Sol, Terra, and Luna, spanning flagship reasoning down to fast, low-cost inference.
Immunologist Derya Unutmaz at The Jackson Laboratory handed GPT-5 Pro an unpublished dataset his team had puzzled over since 2022 — how glucose shapes the way T cells develop and specialize. Within minutes the model pinpointed the likely mechanism, disrupted N-linked glycosylation, and proposed follow-up experiments that later confirmed it. OpenAI published the case on June 23 as evidence that frontier models can now generate original, testable scientific hypotheses, not just summarize what is already known.
OpenAI expanded its Daybreak security program with the full release of GPT-5.5-Cyber, which it calls its strongest model yet for finding, validating, and patching software vulnerabilities — it set a new state of the art on the CyberGym benchmark at 85.6 percent. Alongside it, a new "Patch the Planet" effort funds expert researchers to fix flaws in widely used open-source projects and work directly with their maintainers; more than 30 projects have signed on, with Trail of Bits and HackerOne as partners. OpenAI argues its models now find bugs faster than defenders can fix them, so the bottleneck has shifted to patching.
OpenAI's frontier models and its Codex coding agent are now generally available on Amazon Bedrock, graduating from the limited preview that opened in April. GPT-5.5 runs in AWS's US East region and GPT-5.4 in US East and US West, callable through the Responses API with pricing that matches OpenAI's first-party rates. The move lets AWS customers reach OpenAI models inside their existing security, logging, and compliance controls — a notable thaw between OpenAI and a cloud rival to its main backer, Microsoft.
OpenAI says a new general-purpose reasoning model discovered a counterexample to a 1946 Paul Erdős conjecture about optimal unit-distance configurations, a problem mathematicians had assumed was solved by the obvious square-grid construction. Mathematicians Noga Alon, Melanie Wood, and Thomas Bloom reviewed the result and published companion remarks endorsing the disproof. The claim arrives seven months after OpenAI's previous Erdős announcement was shown to be a misrepresentation of prior literature, so the named verifications matter.
OpenAI flipped ChatGPT's default model to GPT-5.5 Instant,
replacing GPT-5.3 Instant for free, Plus, Pro, Business, and Enterprise
users while keeping the same low-latency profile. The company says the
new model substantially reduces hallucinations in law, medicine, and
finance, and posts an AIME 2025 math score of 81.2 versus the prior
65.4. GPT-5.5 is also live in the API as chat-latest; OpenAI will
keep GPT-5.3 available to paid API users for three more months before
retiring the older default entirely.
On May 4 both frontier labs announced finance-industry-backed enterprise AI services companies. Anthropic revealed a joint venture with Blackstone, Hellman & Friedman, and Goldman Sachs — also backed by Apollo Global Management, Sequoia, GIC, General Atlantic, and Leonard Green — that embeds Applied AI engineers into mid-sized community banks, manufacturers, and regional health systems for Claude integrations. OpenAI's parallel "The Development Company" raised $4 billion at a $10 billion valuation alongside TPG, Brookfield, Advent, and Bain Capital. Both adopt Palantir's forward-deployed engineer model — sending lab engineers into client organizations rather than selling SaaS — a structural signal about how mid-market AI distribution is going to be sold.
AWS and OpenAI announced on April 28 that GPT-5.5, GPT-5.4, the Codex coding agent, and a new Amazon Bedrock Managed Agents capability are now in limited preview for enterprise customers via Bedrock — OpenAI's first major distribution outside the seven-year Microsoft Azure exclusivity. Customers can evaluate and deploy OpenAI models alongside Anthropic, Meta, Mistral, Cohere, and Amazon's own models in a single Bedrock console with unified security, governance, and cost controls. The launch follows last week's amended Microsoft-OpenAI agreement that ended exclusive cloud rights through 2032 and signals a multi-cloud distribution era for frontier models.