A teenager boasted of having "done a bottle shop" in Facebook messages that helped police prove he had robbed one at knifepoint.
The online exchanges, littered with "rolling on the floor laughing" emojis, were revealed in documents tendered to the ACT Supreme Court on Thursday.
Banks man Lachlan Smith, 18, was facing a sentence hearing after pleading guilty to charges of aggravated robbery, trespassing and going equipped for theft.
Agreed facts show he was wearing a balaclava and brandishing a Kukri knife, which is similar to a machete, when he and another male held up the BWS Erindale bottle shop last August.
Smith pointed the knife at a worker, who was preparing to close the store, and demanded he open the till.
The fearful employee complied, allowing Smith and his co-offender to steal more than $1600 worth of cash, cigarettes and alcohol.
Smith was up to no good again two nights later, when he trespassed on the Kaleen property of a scared couple while carrying the same knife used in the robbery.
When he was ultimately arrested last September, police found him wearing some of the same clothing he had on in CCTV footage of the crimes. The knife was also discovered under his bed.
While Smith initially denied involvement in either incident, an analysis of his phone told a different story.
Police officers who reviewed his Facebook messages found he had boasted of being "fresh outta the pen" and having "done a bottle shop the other day", netting himself "cash, ciggies n bottles" in the process.
Encouraged by the recipients of his messages, who invariably responded with "rolling on the floor laughing" emojis, he kept gloating with phrases that are commonly used by criminals.
While he later called his mother from prison and told her to "log in and f---ing get rid of it", it was too late and he ultimately pleaded guilty.
His lawyer, Jonathan Cooper, said on Thursday it was unfortunate Smith had grown up around this sort of "criminal talk", antisocial attitudes and drugs.
Mr Cooper told the court the teenager was "seeking a therapeutic order of some kind", suggesting he could be bailed to attend a residential drug rehabilitation facility, with sentencing deferred while he completed a program.
The lawyer alternatively proposed a referral to the court's drug and alcohol sentencing list, where Smith would undergo assessments of his eligibility and suitability for a treatment order.
"Deal with the drugs, deal with the problem," Mr Cooper told the court.
Prosecutor Elizabeth Wren did not oppose the drug and alcohol assessment referral, which Justice David Mossop agreed to make.
Justice Mossop remanded Smith, who has been behind bars since his arrest, in custody ahead of an assessment later this month.
