diff --git a/AGENTS.md b/AGENTS.md
index 0abb41d9..26564d30 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -120,6 +120,12 @@ See [§0](#0-never-crash). It outranks every other engineering rule.
 See `CLAUDE.md`: pure Rust, dependency layering (`cargo xtask layers`), exact `Tick` time, everything is
 a command, everything is agent-drivable, and the quality gates (`cargo xtask ci`) before every commit.
 
+Shared real-file test corpora (Photoshop-authored PSDs, etc.) live in
+[`storytold/photocraft-corpus`](https://github.com/storytold/photocraft-corpus), explained in
+[craftrules `standards/test-corpora.md`](https://github.com/storytold/craftrules/blob/main/standards/test-corpora.md).
+Never commit large binary fixtures to this repo; fetch them pinned by commit and sha256-verified,
+as PhotoCraft does with `cargo xtask corpus`.
+
 ## See also
 
 - [CONTRIBUTING.md](CONTRIBUTING.md) and [docs/contributing.md](docs/contributing.md): setup, gates, commits, how to add things