diff --git a/docs/data-model.md b/docs/data-model.md
index a9e49c2..2d448b2 100644
--- a/docs/data-model.md
+++ b/docs/data-model.md
@@ -152,6 +152,7 @@ erDiagram
         text endpoint "which backend served it: iguana/... | berget/... (berget = audio left the homelab)"
         float audio_seconds
         text error_kind "typed: interrupted | transcription_failed — never a provider string"
+        bool had_video "the file carried a video track; only its audio was used (migration 018)"
         timestamptz created_at
         timestamptz finished_at
     }
@@ -223,7 +224,7 @@ mechanism.
   grounds that it holds only public caption content, and a recorded meeting is the opposite.
   `user_id NOT NULL ... ON DELETE CASCADE`, FORCE RLS'd. `status` runs `queued → transcribing →
   done | failed`; `done` requires `content`, `failed` requires a typed `error_kind` (CHECK
-  constraints). `endpoint` records which backend served it — `berget/...` means the audio left the
+  constraints). `had_video` (migration 018) records that the file carried a video track — a Teams meeting with the camera off is still a video file — so the page can say only its audio was used and the video was discarded. `endpoint` records which backend served it — `berget/...` means the audio left the
   homelab. The audio itself is never stored. `segments` keeps the timestamps (re-transcribing 90
   minutes costs ~7). Unlike `summary_actions`/`login_events` it **does** cascade on user deletion.
 - **LOGIN_EVENTS** (migration 010) — throttled one-row-per-(user, date) login stamp. Used by the