MCP Registry Drift Panel v1

A longitudinal panel of the official Model Context Protocol (MCP) registry: 120 observations spanning 2026-04-30 to 2026-07-28 (88.6 days), covering the registry as it grew from 3,510 to 18,966 active servers. Each observation records, per server, whether its published descriptor and description changed since the prior observation. Server names and content hashes are pseudonymized with change-preserving HMAC-SHA256 tokens; every temporal finding reproduces from this file. This is the dataset behind the measurement paper "Registry Descriptions Go Stale Unevenly: An 89-Day Measurement of Model Context Protocol Drift, and Why Drift-Ranked Re-Auditing Under-Covers It" (preprint: DOI 10.5281/zenodo.21728370) Version 2 adds figures_addenda.json (five results computable from the panel but unreported in v1: the description-level autocorrelation conditional, a tie-break diagnosis of the targeting curve, the ranking rule, the conditional's base composition, and a bound on the name-reappearance channel) and ships the analysis code (paper_figures.py, paper_figures_addenda.py, make_paper_figure.py) so every figure regenerates from the deposited panel with no dependencies beyond the Python standard library.v3: analysis scripts now run directly against this package; reproducibility claims scoped (see Expected differences in DATASET_CARD.md). Data files are byte-identical to v2.