The 17-year-old, who cannot be named for legal reasons, was sentenced to six years and eight months in prison after writing a manifesto aiming to inspire other terrorists.
He detailed plans to firebomb synagogues and other buildings as part of what he believed was an upcoming “race war”.
Before being arrested, he wrote that his upcoming 12 weeks of study leave would be “showtime”.
“I think I am moments away from constructing bombs and weapons, how exciting,” a diary entry added.
The boy was convicted of six terror offences, including preparing acts of terrorism, disseminating terrorist publications and possessing material for terrorist purposes.
Sentencing him at Manchester Crown Court on Tuesday, Judge David Stockdale QC said: “While your youth is a powerful mitigating factor, it is also a feature of this case, which is perhaps most disturbing.
“You are a highly intelligent, widely read, quick-thinking and articulate young man. Given the development of your intellect, the breadth of your reading and your obvious thirst for knowledge, it is a matter of infinite regret that you pursued at such a young age a twisted and – many would say – a sick ideological path.”
Medical experts for both the prosecution and defence agreed the teenager was suffering from an autism spectrum disorder that played a part in his offending, the judge said.
When he was arrested in March, police found a piece of paper in his pocket containing a message on code that said: “Killing is probably easier than your paranoid mind thinks. You’re just not used to it ... good hunting Friday.”
During his arrest, the boy was carrying a second piece of paper containing a drawing of a fellow school pupil being beheaded.
Prosecutors said he had called for the student’s death, and had described how he wanted to violently attack a second pupil – who he thought was gay – as “judgement exacted on the lowest of the low, as deserved”.
Michelle Nelson QC told Manchester Crown Court: “Assaults upon fellow students, who had no place in the new world order, was in line with that; it was something he saw as part of generating race war and chaos.”
After reading Norway shooter Anders Breivik’s manifesto, which called for lone-wolf terror attacks to fight the “genocide” of white people, the teenager started drafting his own.
The document was entitled: “Storm 88: A manual for practical sensible guerrilla warfare against the kike [offensive term for Jewish] system in Durham city area, sieg hiel.”
It listed proposed attack targets in Durham, including schools, public transport and council buildings.
Writing on the Fascist Forge forum, the teenager claimed a race war was “inevitable”, and supported accelerationism, which calls for the demise of the liberal democratic “system” through violence.
Prosecutors said they had not identified a “particular act or acts” of terrorism that the boy was going to commit, but that he had been preparing for some kind of atrocity since October 2017.
He denied all offences, claiming he had adopted the terrorist persona for “shock value” and did not want to carry out attacks, but was convicted unanimously of all charges in November.
The teenager wrote that an extremist contact had warned him of an imminent police raid a month before his arrest, prompting him to start deleting files from his devices.
At his first appearance at Westminster Magistrates’ Court last April, prosecutor Kristel Pous said: “Between 10 and 14 February, he was tipped off by the Fascist Forge network that the police raid was imminent, and he proceeded to delete all his files.”
Chief magistrate Emma Arbuthnot said she was “very concerned” and asked police to investigate the claim.
A spokeswoman for Counter Terrorism Policing North East said no further evidence was found, adding: “Although there is evidence he did delete a number of files around 14 February, there’s no actual evidence to support the fact he was tipped off or implicating a third party. All the files deleted at that time were recovered.”
The teenager demonstrated a fascination with mass killers including Breivik, the Oklahoma bomber, Columbine shooters and Unabomber.
The court heard that the boy had been an “adherent of a right-wing ideology” since the age of 13, and that his views became more extreme as he immersed himself in fascist websites and forums.
By 2017, he was describing himself as a neo-Nazi and operated a since-deleted Twitter account.
His racist and homophobic tweets drew the attention of police but when he was interviewed in September that year, he claimed they were posted “for a laugh”.
The teenager initially agreed to take part in the Prevent counter-terror programme but later stopped engaging.
The boy claimed he was not an extremist, but started another Twitter account and continued communicating with contacts, while accessing a “large quantity of extreme right-wing literature”.
The court heard he had steeped himself in antisemitic conspiracy theories and ranted about Jewish school governors, MPs and the press.
In August 2018, he described himself as a “radical national socialist” and follower of Adolf Hitler, saying he had read Mein Kampf and had a photo of the Nazi leader on his phone.
Prosecutors said the boy obtained and shared terror manuals on making explosives and firearms on the Ironmarch and Fascist Forge online forums, but also drew on jihadi propaganda.
He had searched for Isis execution videos and used al-Qaeda literature, and a jihadi guide on making deadly poisons, including ricin.
By November 2018, he had progressed to extreme occult neo-Nazism, which has gained traction in branches of the UK’s banned National Action terrorist group, and voiced support for satanism.
The teenager declared his support for the “siege” ideology, which was started by an American neo-Nazi and advocates the use of terror attacks to trigger a race war and chaos.
“Democracy is very much a dead system; political violence therefore, can only help us,” he wrote. “The white race is being silently genocided, the west is dying.”
Det Ch Supt Martin Snowden, the head of Counter Terrorism Policing North East, said the decision to prosecute a young person was “never easy”.
“However, we will always take necessary and proportionate action to keep our communities safe,” he added.
“Cases such as this highlight the dangers our young people face today online. The negative influence and powerful manipulation that takes place by those who seek to radicalise them cannot be underestimated.“
Counterterror police have named right-wing extremism as the fastest-growing terror threat to the UK, although Islamists still make up the largest proportion of investigations.
The largest group of people referred to the Prevent counter-extremism programme are individuals with a “mixed, unstable or unclear ideology”, including obsessions with violence and massacres.
Of the 24 terror plots foiled by security services since March 2017, 16 were Islamist and eight were far-right.