diff --git a/TODO.md b/TODO.md
index bec722f..aaf3cbb 100644
--- a/TODO.md
+++ b/TODO.md
@@ -43,6 +43,38 @@ though it already exits cleanly when it finds no database.
 Update `user/CLAUDE.md` to name the command in the same change, or the doc and
 the layout disagree the moment this ships.
 
+### Prior art to discuss: akitaonrails/ai-memory
+
+<https://github.com/akitaonrails/ai-memory> — read 2026-08-13. Solves a superset
+of this: cross-vendor long-term memory so you can quit Claude Code mid-task and
+continue in Codex without re-explaining. A Rust binary plus a data dir, served
+over MCP, with `install-mcp` and `install-hooks` subcommands.
+
+Worth stealing even if we never run it:
+
+- **`_global` scope.** A reserved project that is unioned into every query —
+  standing personal rules, tech choices, style. Exactly what `user/CLAUDE.md`
+  is. Confirms the split we already made.
+- **Page categories**: `_rules/`, `decisions/`, `procedures/`, `gotchas/`.
+  Better than one growing file. Our `user/CLAUDE.md` is six sections and will
+  not stay readable at twenty.
+- **Authority-aware retrieval.** Maintained rules outrank episodic session
+  evidence, but do not become absolute. A good answer to "the doc says X but
+  the code does Y" — which bit us today with the stale `pm2` rule.
+- **`.ai-memory.toml` marker file** in a repo ancestor to pin which
+  workspace/project a directory belongs to. Directly relevant to our manifest's
+  "only if this path exists" condition — a marker is more explicit than a path
+  test.
+- **`bootstrap`** seeds pages from `git log`, README, `docs/`, module headers.
+  The thing we would want when adding a new machine or repo.
+
+The real decision: it is a **running service** (daemon, SQLite, FTS5,
+embeddings, MCP, hooks). Ours is plain files and symlinks, readable with `cat`,
+and works when nothing is installed. That simplicity is a feature, especially
+given today's "code on disk is not what is running here" problem. Options:
+adopt it, borrow the taxonomy only, or stay flat and revisit when the flat file
+gets unreadable.
+
 ### Open questions
 
 - Which files are genuinely universal vs this-machine-only? Right now