diff --git a/AGENTS.md b/AGENTS.md
index a64073877b..db9fd04028 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -52,6 +52,7 @@
 
 - Runtime baseline: Node **22+** (keep Node + Bun paths working).
 - Install deps: `pnpm install`
+- If deps are missing (for example `node_modules` missing, `vitest not found`, or `command not found`), run the repo’s package-manager install command (prefer lockfile/README-defined PM), then rerun the exact requested command once. Apply this to test/build/lint/typecheck/dev commands; if retry still fails, report the command and first actionable error.
 - Pre-commit hooks: `prek install` (runs same checks as CI)
 - Also supported: `bun install` (keep `pnpm-lock.yaml` + Bun patching in sync when touching deps/patches).
 - Prefer Bun for TypeScript execution (scripts, dev, tests): `bun <file.ts>` / `bunx <tool>`.