Ogham is an early medieval script in which letters are represented by sets of notched or scored lines cut along the edge of a stone, and this particular pillar reads, across its north-west edge, the personal name formula LOGITTI MAQI ERPENN, meaning something close to "Logitt, son of Erp". These are likely the names of real individuals from early Christian Ireland, the stone probably marking a burial or a territorial claim. What makes the Cool stone slightly unusual is that part of its inscription has been swallowed by the ground. The first four letters and the opening stroke of the first T are now buried, meaning the complete text survives only in the scholarly record rather than in what is visible to the eye.

R.A.S. Macalister, whose 1945 corpus of Irish ogham stones remains a foundational reference, recorded the full reading, working from what was then accessible. There is one further curiosity in the inscription: the letter P, rare in the ogham alphabet and sometimes representing a borrowed sound from Latin or British, is rendered here using the I-forfid, a supplementary character cut onto the face of the stone rather than its edge. This small technical detail hints at the complexity of a script that was still evolving as it came into contact with Latin literacy. The stone also carries crosses on both faces, one of Latin type with large, bulbous terminals on the WSW face, the other a roughly equal-armed cross with expanded terminals on the opposite face. The crosses appear to have interacted directly with the ogham text; the final strokes of the second N seem to have been cut short, their function absorbed by the placement of the cross beside them. The stone is oriented roughly NNW to SSE and measures 1.92 metres in height, with a base of 0.48 by 0.13 metres.