[1] Habitat photographs of a taxon matching the description of N. abgracilis appeared in a 2008 issue of the German-language periodical, Das Taublatt,[2] and in the second volume of Stewart McPherson's 2009 work, Pitcher Plants of the Old World.

[3] In both it was identified as a variant of N. alata[1] (at the time considered a highly variable and widespread species, but which has since been split into a number of daughter taxa).

[4][5] Nepenthes abgracilis was formally described by botanists Martin Cheek and Matthew Jebb in the e-published[6] 6 December 2013 issue of Phytotaxa.

The stem has a "moderately dense" covering of sessile, depressed-globose, red glands measuring 0.05 mm in diameter.

It clasps the stem for three-quarters to four-fifths of its circumference, having an angled insertion and forming wings 0.3–0.4 cm wide.

[1] Rosette, lower and intermediate pitchers remain unknown as they do not form part of the examined herbarium material.

Sessile glands similar to those found on the stem are also present on the exterior of the upper pitchers, where they occur at a density of 3–4 per mm².

In these aerial traps the wings are reduced to a pair of ridges on the ventral surface of the pitcher cup.

Though the describing authors noted the presence of a basal midline ridge on the lower lid surface of a herbarium specimen, they concluded that this was likely a preservation artefact.

The nectar glands of the lower surface of the lid number more than 100, at least 95% of which are of a single type that is quite uniform in size and shape.

The area around the upper part of the basal ridge bears around 20 narrowly elliptic-oblong glands, each measuring roughly 0.75 by 0.25 mm.

The upper pitchers are completely devoid of an indumentum apart from a small number of inconspicuous, simple hairs (0.05–0.10 mm long) near the peristome.

[1] Since it is only known from a single locality, Cheek and Jebb informally assessed the conservation status of N. abgracilis as Critically Endangered based on the IUCN criteria.

The authors noted that while there is mining activity for metal ore on Mount Legaspi, this is currently at lower elevations than the 670 m at which the species was collected.