NEW YORK – If you’re going to let dinosaurs run amok, it’s good to have some ground rules.

That’s how screenwriter David Koepp saw it, anyway, in penning the script for “Jurassic World Rebirth,” which opens in theaters July 2. Koepp wrote the original “Jurassic Park and its 1997 sequel, “The Lost World. But “Rebirth,” the seventh film in the franchise, marks his return to the franchise he helped birth.

And Koepp, the veteran screenwriter of “Carlito’s Way” and “Mission: Impossible,” saw it as a chance to get a few things in order for a movie series that had perhaps strayed too far from its foundational character. Inspired by the animator Chuck Jones, Koepp decided to put down a list of nine commandments to guide “Jurassic World Rebirth” and future installments.

Jones had done something similar for the Roadrunner cartoons. His “commandments” included things like: the Roadrunner never speaks except to say “meep meep”; the coyote must never catch him; gravity is the coyote’s worst enemy; all products come from the ACME Corporation.

“I always thought those were brilliant as a set of organizing principles,” Koepp says. “Things become easier to write when you have that, when you have a box, when you have rules, when you agree going in: ‘These we will heed by.’ So I wrote my own, nine of them.”

Koepp shared some — though not all of them — in a recent interview.

1. The events of the first six movies cannot be contradicted

“I hate a retcon. I hate when they change a bunch of things: ‘Oh, that didn’t actually happen. It was actually his twin.’ I don’t like other timelines. So I thought: Let’s not pretend any of the last 32 years didn’t happen or happened differently than you thought. But we can say things have changed.”

2. The dinosaurs are animals, not monsters

“On the first movie, anyone working on the movie would get fined for referring to them as monsters. They’re not monsters, they’re animals. Therefore, because they’re animals, their motives can only be because they’re hungry or defending their territory. They don’t attack because they’re scary. They don’t sneak up and roar because they want to scare you.”

3. Humor is oxygen.

“You can’t forget it.”

4. Science must be real

“The tone that Steven (Spielberg) found and I helped find in that first movie is really distinctive. I haven’t gotten to work on a movie with that tone since then. So to go back to that sense of high adventure, real science and humor, it was just kind of joyful.”

5. The tone must never been ponderous or self-serious

“And then there were a number of other rules that I would define as trade secrets. So I’ll keep them to myself.”