The digital editing of early modern correspondence requires precise modeling of historical texts as well as the integration of modern tools for annotation and analysis. The project “Die sozinianischen Briefwechsel” (http://www.sozinianer.de

) provides a digital edition of letters from the circle of the anti-Trinitarian Socinians of the seventeenth century. Based on the ATAG model (Applied Text as Graph), texts are represented in a labeled property graph down to the level of individual characters, enabling flexible annotations, recursive comments, and algorithmic analyses (cf. Kuczera 2024; Haentjens/Birnbaum 2017).

This article presents an innovative approach to the automated annotation of these letters: the integration of Anthropic’s language model Claude via the interface module MCP (Model Context Protocol) enables the identification, typing, and semantic enrichment of annotatable text passages while considering only the already existing metadata on persons, places, and objects. The annotations thus generated are integrated as annotation nodes into the existing Neo4j graph database and are subsequently available both in the web frontend and for algorithmic analysis. During the annotation process, Claude can access previously annotated texts and registers and orient itself accordingly.

The aim of this article is to present the technical and methodological workflow combining ATAG, Claude with MCP, and Neo4j, and to analyze it with regard to editorial practice and annotation fidelity. The original contribution lies in the technical integration of an LLM annotator into a granularly structured editorial system with direct graph anchoring, which for the first time enables direct semantic enrichment at the character level.