On information – Harel in Haaretz:

‘The night before Hamas' assault, an accumulation of signs or fragments of information aroused certain concern. Two telephone consultations were held during the night among the southern region of the Shin Bet security service, the IDF’s Intelligence Corps, the operations division and Southern Command with the knowledge of IDF Chief of Staff Herzl Halevi. A separate consultation was held at the Shin Bet with the head of the agency, Ronen Bar.
There was significant nervousness at the command. At the Shin Bet, it was claimed that the information involved an exercise. The Intelligence Corps shared this assessment and didn’t recommend any increased state of alert. That was the case with both of the consultations in the space of a few hours. On the Shin Bet’s recommendation and with military approval at the highest level, no steps were taken.’

Read full article here.

NYT gave a day earlier slightly different information:

‘Before the attacks: Israeli intelligence detected an unusual surge in activity on Gazan militant networks it monitors and alerted the Israeli soldiers guarding the Gazan border.

But the warning wasn’t acted upon, either because the soldiers didn’t receive it or the soldiers didn’t read it.’

Read the article here.

Both versions are devastating for army and intelligence services.

You don’t have to start a preventive attack in case of doubt, but you could place your soldiers at a slightly higher state of alert. Of course there are risks, higher state of alert means soldiers probably more trigger happy, which might result in the loss of innocent live.

But based on both articles, not only the secret services but also the army itself appeared to be a bit cavalier about the warnings, just another exercise, Hamas loves to exercise, no worries.