diff --git a/tools/egg-bundler/docs/output-structure.md b/tools/egg-bundler/docs/output-structure.md
index 9670d81f1c..60e3cc8fd1 100644
--- a/tools/egg-bundler/docs/output-structure.md
+++ b/tools/egg-bundler/docs/output-structure.md
@@ -40,6 +40,13 @@ is keyed by relKey, output-dir absolute paths, precomputed original app absolute
 paths, and manifest `resolveCache` request aliases. Application code and plugins
 may still use `fs` for resources such as config, views, or assets.
 
+When the bundler generates a missing `.egg/manifest.json` with
+`metadataOnly: true`, Egg also records convention-based dynamic lookups from each
+load unit into the manifest `resolveCache` and `fileDiscovery`, including
+`agent`, `app`, `app/extend/*`, and `app/middleware/*`. This lets bundled
+single-mode workers resolve plugin agent hooks, extensions, and middleware that
+are normally discovered later during runtime loading.
+
 ## `bundle-manifest.json`
 
 A reference file produced by `Bundler` (not consumed at runtime). Shape: