Writing the Rules Down.
A specification is a set of priorities for when good goals conflict.
Developers increasingly publish what their models are meant to do. Anthropic published the constitution used in Constitutional AI in 2023; OpenAI’s Model Spec (2024) sets out objectives, rules and defaults, and a chain of command for whose instructions take precedence — the platform, then the developer, then the user. A specification matters most where goals conflict: a request that is usually benign but occasionally dangerous, a user instruction that contradicts a developer’s, a truthful answer that will upset. It says which consideration wins, and gives examples.
Specifications act on models through training — they generate and filter fine-tuning data, they instruct the judges of AI feedback (plate XVIII.9), and newer methods train models to reason about the specification explicitly before answering — and through evaluation, which checks behaviour against them. The workshop uses a stylised model of one such conflict: requests with a latent level of harm, a model that perceives it imperfectly, and a specification whose relative weight on helpfulness and caution sets where the model declines.
Below: the rates of declining legitimate requests and of helping harmful ones, as the specification’s weight shifts between helpfulness and caution; the chosen balance is marked.
- Describe what a model specification contains.
- Explain the chain of command among instructions.
- Show how priorities move a refusal threshold.
- Name how specifications reach a model.
Priorities, not just rules
With equal weight on helpfulness and caution, this model declines 7.8% of legitimate requests and helps 2.4% of harmful ones. Shifting the specification towards helpfulness (8 to 2) cuts the first to 1.4% and raises the second to 24.4%; shifting it towards caution (2 to 8) does the reverse: 26.7% and 0.0%. No setting of the weights removes both errors, because the model perceives harm imperfectly; the specification only chooses which error to make more often.
That is the honest content of a specification: a statement of priorities for unavoidable trade-offs, made public so it can be criticised. Real specifications go further than a single threshold — they distinguish kinds of harm and kinds of request, prefer safe partial help to blanket refusal, and settle whose instructions win — but the structure is the same. What a specification cannot do by itself is improve the model’s judgement of which requests are harmful; that is a matter of training and capability (plate XX.3).
Terms
- Model specification
- A document stating how a model should behave and resolve conflicts.
- Constitution
- A set of principles used to train and judge a model.
- Chain of command
- The order in which platform, developer and user instructions take precedence.
- Default behaviour
- What a model does when no instruction says otherwise.
Sources
- OpenAI, “Model Spec”, May 2024 (objectives, rules, defaults; chain of command).
- Anthropic, “Claude’s Constitution”, May 2023.
- Guan et al., “Deliberative Alignment: Reasoning Enables Safer Language Models”, arXiv:2412.16339, 2024.