diff --git a/docs/nostr-event-schemas.md b/docs/nostr-event-schemas.md
index eb2feb11..5de8cf6d 100644
--- a/docs/nostr-event-schemas.md
+++ b/docs/nostr-event-schemas.md
@@ -163,7 +163,7 @@ import { updateWatchHistoryListWithDefaultClient } from "./nostrWatchHistoryFaca
 
 > **Publishing note:** Session actors only emit passive telemetry (for example, view counters) and must **not** sign video comments. Require a logged-in Nostr signer for comment publishing via [`commentEvents`](../js/nostr/commentEvents.js).
 
-Video posts now include a required storage pointer tag (`['s', '<provider>:<prefix>']`). The `<prefix>` should resolve to the public storage base for the video assets (for example, a public bucket URL plus the object key without its extension). Clients derive `info.json` by appending `.info.json` to the prefix (or by combining a path-style prefix with the hosted URL origin if needed).
+Video posts now include a required storage pointer tag (`['s', '<provider>:<prefix>']`). The `buildVideoPostEvent` helper automatically generates this tag from available metadata (`infoHash`, `url`, or `videoRootId`) if it is omitted from the input. The `<prefix>` should resolve to the public storage base for the video assets (for example, a public bucket URL plus the object key without its extension). Clients derive `info.json` by appending `.info.json` to the prefix (or by combining a path-style prefix with the hosted URL origin if needed).
 
 Video posts should treat `videoRootId` as the stable series identifier that remains unchanged across edits and deletes. File fingerprints such as `infoHash` or `fileSha256` live alongside the content payload so media swaps do not break the version chain.
 
diff --git a/js/nostrEventSchemas.js b/js/nostrEventSchemas.js
index 8a111d55..e01a3436 100644
--- a/js/nostrEventSchemas.js
+++ b/js/nostrEventSchemas.js
@@ -9,6 +9,10 @@ import {
   WATCH_HISTORY_LIST_IDENTIFIER,
   WATCH_HISTORY_VERSION_TAG_VALUE,
 } from "./config.js";
+import {
+  buildStoragePointerValue,
+  deriveStoragePointerFromUrl,
+} from "./utils/storagePointer.js";
 
 export const NOTE_TYPES = Object.freeze({
   VIDEO_POST: "videoPost",
@@ -889,6 +893,38 @@ export function buildVideoPostEvent(params) {
     tags.push(...sanitizedAdditionalTags.map((tag) => tag.slice()));
   }
 
+  const hasSTag = tags.some((t) => t[0] === "s");
+  if (!hasSTag) {
+    let contentObj = content;
+    if (typeof content === "string") {
+      try {
+        contentObj = JSON.parse(content);
+      } catch (e) {
+        contentObj = {};
+      }
+    }
+    contentObj = contentObj || {};
+
+    let pointer = "";
+    if (contentObj.infoHash) {
+      pointer = buildStoragePointerValue({
+        provider: "btih",
+        prefix: contentObj.infoHash,
+      });
+    } else if (contentObj.url) {
+      pointer = deriveStoragePointerFromUrl(contentObj.url);
+    }
+
+    if (!pointer && (dTagValue || contentObj.videoRootId)) {
+      const prefix = dTagValue || contentObj.videoRootId;
+      pointer = buildStoragePointerValue({ provider: "nostr", prefix });
+    }
+
+    if (pointer) {
+      tags.push(["s", pointer]);
+    }
+  }
+
   let serializedContent = "";
   if (typeof content === "string") {
     serializedContent = content;
diff --git a/scripts/agent/validate-events.mjs b/scripts/agent/validate-events.mjs
index dd4fe0bd..d104e29d 100644
--- a/scripts/agent/validate-events.mjs
+++ b/scripts/agent/validate-events.mjs
@@ -1,3 +1,10 @@
+/**
+ * Event Schema Validation Tool
+ *
+ * Scans the codebase for event builder usage and verifies that the output
+ * conforms to the defined schemas in `js/nostrEventSchemas.js`.
+ */
+
 import fs from 'node:fs';
 import path from 'node:path';
 import crypto from 'node:crypto';