--- /dev/null
+# Prompt — Source Metadata Investigation
+
+**Model**: Claude Opus 4.6
+**Date**: 2026-03-12
+
+## Summary
+
+A canonical upstream repository was found at https://github.com/cadsondemak/prompt, owned by Cadson Demak, the designer listed in METADATA.pb. The repository is not a mirror and contains source files. The METADATA.pb source block was updated accordingly.
+
+## Designer
+
+Cadson Demak (info@cadsondemak.com) — a Thai type foundry. The DESCRIPTION.en_us.html explicitly links to `https://github.com/cadsondemak/prompt` as the contribution URL.
+
+## Repository Investigation
+
+- **Checked cache**: `/mnt/shared/upstream_repos/fontc_crater_cache/` — no cached entry for cadsondemak/prompt.
+- **GitHub search**: The repository `https://github.com/cadsondemak/prompt` was found and verified (HTTP 200).
+- **Ownership**: The repository owner is `cadsondemak`, matching the designer credit. It is not a fork.
+- **Description**: "Prompt is a Thai + Latin formal sans serif font family with 18 styles" (51 stars).
+- **Latest commit**: `18f813a4dea16a7ecc6f944053d3ce2cd4d7e824` — "The mark has been fixed. The mark of the letters Ỗ and ỗ has been fixed."
+
+## Source Files
+
+The repository contains the full 18-style family (9 weights × 2 axes: upright and italic).
+
+## Verdict
+
+**Canonical upstream repo found.** `https://github.com/cadsondemak/prompt` is the designer-owned repository. METADATA.pb was updated with `repository_url` and `commit` fields.