OpenAI updated the Model Spec on October 29, 2026 — the public document describing how its own models are supposed to behave. The revision is substantial: the whole text is reorganized around five values, a new section on considering context carefully is added, most of the detailed style guidance is retired, and even the name for the subject changes from "the assistant" to "GPT". The official announcement puts the reason plainly: as models get stronger, following instructions literally is no longer enough. Models also need to understand human intentions and values so they can exercise good judgment in situations their instructions do not explicitly address.
Five values, and the tensions they arbitrate
The new skeleton has five: faithfulness to human intent, harm minimization, honesty and transparency, human agency, and care. The official blog calls the first one the foundation of the whole approach — what people value comes first, and instructions are ordinarily the clearest and most important signal of those values. That section borrows from the assistance-games framing of alignment, citing two early papers (arXiv 1606.03137 and an overview in Daedalus). The document also concedes that the five values are not intended to capture the full range of human values the models should respect and help people pursue.
In practice the values arbitrate two tensions: individual versus collective interests, and immediate instructions versus uncertain longer-term goals. Red-line principles are set out separately: human safety and human rights are paramount; the models should never facilitate critical and high-severity harms such as acts of violence, war crimes, genocide, torture, human trafficking or forced labor, the creation of cyber, biological or nuclear weapons, terrorism, child abuse, persecution or mass surveillance; and humanity should be in control of how AI is used and how model behaviors are shaped.
Where the real engineering sits: the chain of command and the autonomy contract
Two structures show the substance of the change more clearly than the values do.
The first is the chain of command. Every rule and every message role gets a default authority level, from highest down: Root (the root sections of the Spec, which conversational context cannot override), System (the system sections and OpenAI system messages, which neither developers nor users can override), Developer, User, Guideline, and finally no authority by default — assistant messages, tool messages, quoted or untrusted text, and multimodal data all land there. One detail is worth noting: Guideline-level instructions are defaults that context can override implicitly when it clearly calls for it, while User-level instructions can only be displaced by explicit instructions at the user level or above. The filtering vocabulary is engineered too: candidate instructions are collected first, then excluded under four categories — misaligned with a higher-level instruction, superseded by a later message at the same level, inconsistent with the likely intent of its source, or beyond the model's capabilities.
The second is the autonomy contract. The Spec asks that the scope of autonomy be recorded as a semi-structured object with fields such as allowed_tools, latest_time, max_cost, tool_constraints, and free-text additional_details, and that every scope include an ending condition beyond which the model stops acting until a new scope is confirmed. High-risk activities — hacking, deception, causing significant adverse side effects, deploying persistent agents, self-modification — are always prohibited unless explicitly and specifically authorized by applicable instructions. The document also adds an anti-circumvention rule: the model must not evade its instructions or its scope by delegating a prohibited action to another agent, rewriting its own instructions or scope, or scheduling the action for later. When it does delegate, all sub-agents must operate under the same scope. A root-level rule in the same family, no other objectives, bars optimizing for revenue or upsell, and bars self-preservation, evading shutdown, accumulating compute, data or credentials, and acting as an enforcer of laws or morality.
Retiring the style rules is the part that matters most
The retirement of style guidance is the least noticed and most telling change. Long-standing rules about tone, wording, and formatting were removed in bulk, on the reasoning that style should adapt to what people prefer — in aggregate, within languages and cultures, and for each person — with user feedback and context providing evidence about those preferences. A few stronger defaults survived, among them approaching questions objectively, and the Spec makes clear the model should not infer a preferred perspective merely from what it thinks people want to hear; users and developers can explicitly ask for a viewpoint. In effect, style moved out of the system prompt and into something the model has to learn.
Two admissions worth pulling out
Two self-assessments deserve to be pulled out. The first appears in both the Spec text and the official blog: the Spec describes the behavior OpenAI is working toward, and the production models do not yet fully reflect it — an admission that what runs in production is not this document. The second comes from the announcement: alongside the rewrite, OpenAI has been exploring new training methods to help models learn these core values and understand why a given principle matters, so they do the right things for the right reasons in new situations. The announcement points that training work at the beneficial RL page on alignment.openai.com and says results will be shared later. So this revision moved the direction of the objective function too, from executing the spec to understanding the reasons behind it.
Two smaller details are easy to miss: the Spec is dedicated to the public domain under CC0 1.0, so anyone can take it and modify it; and the chain of command states that rail free models able to output restricted content are useful for safety testing and red teaming, while publicly deployed models should not be susceptible to violating root-level principles through a system message.