All I actually want is an LLM which can adhere to a set of rules, like a language spec, library/framework code & then help me make stuff rather than hallucinati

All I actually want is an LLM which can adhere to a set of rules, like a language spec, library/framework code & then help me make stuff rather than hallucination of arbitrary version numbers & staying in an infinite loop of trying every iteration of code by myself in an IDE