diff --git a/AGENTS.md b/AGENTS.md
index 4fff97e..b27c78b 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -23,6 +23,13 @@ Do not invent architecture outside these plans unless explicitly requested.
 - Do not use git worktrees.
 - Local Python venv is direnv-managed via `.envrc` (Python 3.13). After fresh checkout: `direnv allow`, then `pip install -e ./l4d2host -e ./l4d2web pytest`. See README **Local development** for details.
 
+### Planning artifacts
+
+- Design specs live in `docs/superpowers/specs/` as `YYYY-MM-DD-<topic>-design.md`.
+- Implementation plans live in `docs/superpowers/plans/` as `YYYY-MM-DD-<topic>.md` (suffix the topic with `-v1`/`-v2`/etc. if a plan is versioned).
+- Commit both to git as soon as the user approves them.
+- Do not leave specs or plans outside this repo. The `~/.claude/plans/<slug>.md` plan-mode scratch file is acceptable while plan mode is open; the persisted artifact must end up under `docs/superpowers/` and be committed.
+
 ### Naming and boundaries
 
 - Use `l4d2` naming consistently.