diff --git a/projects/AGENTS.md b/projects/AGENTS.md
index 9b279e2..c021b40 100644
--- a/projects/AGENTS.md
+++ b/projects/AGENTS.md
@@ -108,7 +108,19 @@ Key principles:
    modified .org files has balanced parentheses. Use your project's equivalent
    function or the SBCL fallback below.
 
-10. **Commit on the branch** — include the RED and GREEN test output recorded
+10. **Plan the test before running it.** When testing a runnable entry point
+    (daemon, TUI, demo), write down three things first:
+    - **Environment** — use `tmux`, not a PTY shell. tmux provides real
+      `FD-STREAM`s identical to a user's terminal. A plain PTY or subprocess
+      may inherit `SYNONYM-STREAM`s and miss bugs.
+    - **Command** — the exact command the user runs (`passepartout tui`),
+      not a substitute (`load "file.fasl"`, `compile-file`, etc.)
+    - **Pass/fail criteria** — specific checks written before the test runs:
+      "check for COMPILE-FILE-ERROR in output", "check for NOT is not of
+      type SB-SYS:FD-STREAM", "check Goodbye after /quit", "check daemon
+      responds to repl command". Do not accept "it seems to work" as a pass.
+
+11. **Commit on the branch** — include the RED and GREEN test output recorded
     in the .org file as part of the commit message evidence:
     ```
     git add org/ lisp/ docs/