For the first 30 minutes Tool was onstage at the Wells Fargo Center Monday night, a floor-to-ceiling curtain of fringe surrounded the stage. It became at once a translucent screen for the projected orbs of fluid light and a veil between the band and its fervent fans.

The barrier, both tantalizing and frustrating, was a very in-character move for a band that’s always preferred to maintain an air of impenetrable mystery. Monday’s show was the band’s first in Philadelphia since the release in August of Fear Inoculum, Tool’s first album in 13 years and only the fifth studio album in its almost three-decade existence. Still, despite the nearly sold-out crowd’s enthusiastic welcome, singer Maynard James Keenan’s acknowledgment of the audience was limited for most of the show to a single word: “Philly.”

Even after the curtain parted, Keenan kept his distance. He appeared not at the edge of the stage but paced between a pair of isolated risers flanking the drum kit. He was dressed as a punk rock cartoon, crowned by a spiked Mohawk, his eyes shrouded in raccoon black. During the songs’ intricate instrumental passages, he rocked back and forth in an apelike crouch, giving the impression of a caged animal.

Keenan seemed to cede the traditional “front man” role to drummer Danny Carey, clad in 76ers gear and surrounded by an arsenal of drums and synths, all of which (in addition to a massive gong) were called into play on the 10-minute solo that opened the band’s encore. The stage in front of his kit remained empty, a cold, gray gulf stretching between guitarist Adam Jones and bassist Justin Chancellor.

The sterility of the stage set was reflected in the music itself, which felt executed rather than performed. At its best, that resulted in a tautly coiled intensity, as on the crushing riffs of “Schism,” from 2001’s Lateralus, or the elastic bounce of “Jambi,” from Tool’s previous album, 10,000 Days, which found Keenan relaxing to perch on the edge of his mini-stage, kicking his feet while shouting into a megaphone.

For much of the set, though, the four isolated figures onstage felt like craftsmen sticking to a blueprint, impressive in their precision but clinical in their detachment. The skulking bass line of “Aenema” plodded; the visceral sneer of “Swamp Song” was followed by the seemingly endless “Descending,” an epic from the 80-minute Fear Inoculum that veered over the line from mesmerizing to monotonous.

British veterans Killing Joke, the opening act, offered blistering vitality during its 10-song set, singer Jaz Coleman’s vampiric presence provided a taunting violence over churning riffs that served to influence the headliners. Tool instead left its atmospherics to massive projections of haunting animations from its music videos, its stop-motion automata at times more intriguingly vibrant than the flesh-and-blood musicians below.