Full Idea
In this complete concept of possible Peter are contained not only essential or necessary things, ..but also existential things, or contingent items included there, because the nature of an individual substance is to have a perfect or complete concept.
Gist of Idea
The complete concept of an individual includes contingent properties, as well as necessary ones
Source
Gottfried Leibniz (Of liberty, Fate and God's grace [1690], Grua 311), quoted by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 3.3.1
Book Reference
Cover,J/O'Leary-Hawthorne,J: 'Substance and Individuation in Leibniz' [CUP 1999], p.126
A Reaction
Compare Idea 13077, where he seems to say that the complete concept is only necessarily linked to properties which will predict future events - though I suppose that would have to include all of the contingent properties mentioned here.
Related Ideas
Idea 13077 Basic predicates give the complete concept, which then predicts all of the actions [Leibniz]
Idea 13083 The essence is the necessary properties, and the concept includes what is contingent [Leibniz]