The coroner ruled that the inquest would not include evidence from pupils, despite a High Court appeal from the Maguire family. He launched his savage attack on Mrs Maguire with a kitchen knife that he had smuggled into school. He approached from behind, stabbing her eight times and slicing through her jugular vein as she ran screaming.
She was killed during a Spanish lesson at the school by Cornick, who was 15 at the time.
In the lead up to the 61-year-old's murder Cornick had told at least 10 other pupils precisely what he was going to do, where he was going to do it and how he was going to do it, the inquest heard.
A Pulp Fiction-obsessed schoolboy asked a fellow classmate to film the murder of his Spanish teacher who he had boasted he would kill "for £10" before he stabbed her to death, an inquest heard.
Four months before the murder he told one of them that he would "give him a tenner to do it". "I want the capability or choice in a sense to be able to get told off by Maguire and for me to turn around with the skill, pride and power and axe her ******* cockles with a long and shiny blade". "I've lost my confidante because we shared everything together and that's now gone", she said.
"It was abundantly clear to all of them that had they raised the alarm this could have been stopped".
The sister of Ann Maguire, the only teacher to be murdered by a pupil in a classroom in Britain, said she will "never come to terms" with the loss of her "best friend" three years ago.
Cornick and his family were not known to police before the attack, he confirmed.
Friends had said they thought his threats to kill the teacher was just "joking around". "I absolutely am of the view that there is one person responsible for Ann Maguire's death - William Cornick".
Mrs Maguire's widower Don, 65, who attended court with youngest daughter Emma, 34, told how, as he arrived at Leeds General Infirmary, he knew Ann had died because no one would look him in the eye.
The inquest will take place in front of a jury at Wakefield Coroner's Court, and is expected to last two weeks.