methodology.md

Methodology — Nerq MCP-server repository mortality (2026-07)

As of: 2026-07-22 · License: CC-BY 4.0 · Reproducible from public sources with no API key.

This document states how each state in the dataset is derived so the dump can be independently reproduced and spot-checked.

1. Population

Distinct public GitHub repositories (owner/repo) linked from indexed Model Context Protocol (MCP) servers. 28,824 distinct repositories in this dump. Population definition is honest and bounded: it is the set of GitHub repositories reachable from the MCP servers Nerq indexes, not "all MCP servers that have ever existed."

2. Reads (source of truth)

For each repository, two first-hand reads are taken (provenance = own):

1. HTTP status of the repository — 200 reachable, 404 gone (deleted or made private).
2. Last commit timestamp — the latest entry in the repository's public commits.atom feed (https://github.com/{owner}/{repo}/commits.atom). No API key. Not rate-limited. The timestamp is the repository's own last public commit on its default branch; it is a repository fact, not an assertion about any person.

3. State derivation (exact rules)

Let age = observed_date − last_commit in days. Then:

if http_status == 404:                      state = "deleted"     # gone or made private
elif last_commit is unreadable/none:        state = "unknown"
elif age <= 180:                            state = "alive"
elif 180 <  age <= 365:                     state = "dormant"
else (age > 365):                           state = "abandoned"

• deleted is authoritative on the HTTP read (404), heuristic on the cause (deleted vs private).
• alive / dormant / abandoned are heuristic thresholds on commit recency. The thresholds (180 / 365 days) are stated here and are the only knobs; changing them re-buckets the same reads.
• unknown (41 rows) is recorded, not guessed — the row exists so the absence is auditable.

4. Interval-censoring

An observation dates a state, not a transition. A deleted row means "reachable-or-not was 404 on observed_date"; the actual deletion happened at some unknown point between the repo's last_commit and observed_date. This dump is a single seed day (2026-07-22), so death dates are interval-censored to [last_commit, 2026-07-22]. The living series narrows these with dated re-probe rows; collection gaps (a known one on 2026-07-30) are disclosed, and any transition spanning a gap is censored to the surrounding interval rather than pinned.

5. Reproduction

To reproduce any single row: fetch https://github.com/{entity_id} (expect 200 or 404) and https://github.com/{entity_id}/commits.atom (read the first <updated> timestamp), then apply the rules in §3 with observed_date = 2026-07-22. No credentials required.

6. Known boundaries

• commits.atom reflects the default branch only; a repo committing on a non-default branch could read as more stale than it is.
• The 180-day boundary class (repos whose last commit sits within a few days of the threshold) may flip between alive and dormant depending on the exact read time.
• 404 conflates deletion and privatization; the dataset does not claim to distinguish them.