fix(desktop): omit invalid snapshot imeta thumbnails (#1800)

Signed-off-by: Will Pfleger <pfleger.will@gmail.com>
Co-authored-by: npub1mn7jgtj4w2pd0g0zeuhxsa6jy6p0rewxz4kujt98my82ahfmp72sxjexk7 <dcfd242e557282d7a1e2cf2e6877522682f1e5c6156dc92ca7d90eaedd3b0f95@sprout-oss.stage.blox.sqprod.co>

desktop/src/features/agents/ui/AgentSnapshotSendDialog.tsx

@@ -171,9 +171,6 @@ export function AgentSnapshotSendDialog({
           memorySourcePubkey: linkedAgentPubkey,
         }),
       destination.id,
-      // Pass the agent's avatar URL as the NIP-92 thumb hint so the recipient
-      // card can show the avatar instead of the generic Bot icon.
-      persona.avatarUrl ?? undefined,
     );
     // Phase transitions (done/error) are driven by beginSend via setState
     // inside the controller; the mirror effect above keeps `step` in sync.

desktop/src/features/agents/ui/agentSnapshotSend.test.mjs

@@ -15,6 +15,7 @@ import {
   recordTimeoutFromRejection,
   clearTimeoutState,
 } from "../../moderation/lib/timeoutStore.ts";
+import { buildOutgoingMessage } from "../../messages/lib/imetaMediaMarkdown.ts";
 
 // ── isSendableDestination ─────────────────────────────────────────────────────
 
@@ -403,6 +404,54 @@ test("runSendPipeline_checkpoint2_blocks_upload_after_encode", async () => {
   );
 });
 
+test("runSendPipeline_avatar_bearing_snapshot_omits_thumb_and_keeps_filename", async () => {
+  let sentMediaTags = null;
+
+  const result = await runSendPipeline({
+    channelId: "ch-1",
+    checkEligibilityFn: () => null,
+    encodeFn: async () => ({
+      fileBytes: [1],
+      fileName: "avatar-bearing.agent.json",
+    }),
+    uploadFn: async () => ({
+      url: "https://example.com/avatar-bearing.agent.json",
+      sha256: "a".repeat(64),
+      size: 1,
+      type: "application/json",
+      uploaded: 0,
+      // This represents an upload descriptor that happens to include a thumb.
+      // A snapshot send must not serialize it as NIP-92 imeta metadata.
+      thumb: "https://example.com/avatar.png",
+    }),
+    sendFn: async ({ mediaTags }) => {
+      sentMediaTags = mediaTags;
+    },
+    setStateFn: () => {},
+    buildMessageFn: (descriptor) => buildOutgoingMessage("", [descriptor]),
+  });
+
+  assert.equal(result, true);
+  assert.deepEqual(sentMediaTags, [
+    [
+      "imeta",
+      "url https://example.com/avatar-bearing.agent.json",
+      "m application/json",
+      `x ${"a".repeat(64)}`,
+      "size 1",
+      "filename avatar-bearing.agent.json",
+    ],
+  ]);
+  assert.ok(
+    sentMediaTags[0].includes("filename avatar-bearing.agent.json"),
+    "snapshot imeta must retain its filename",
+  );
+  assert.ok(
+    !sentMediaTags[0].some((entry) => entry.startsWith("thumb ")),
+    "snapshot imeta must not include a thumb field",
+  );
+});
+
 test("runSendPipeline_happy_path_sets_all_phases", async () => {
   // All checkpoints pass and encode/upload/send succeed — full phase sequence.
   const states = [];

desktop/src/features/agents/ui/useSnapshotSendController.ts

@@ -212,10 +212,6 @@ export async function runSendPipeline(deps: {
   };
   checkEligibilityFn: () => string | null;
   channelId: string;
-  /** Optional avatar URL emitted as the NIP-92 `thumb` field on the snapshot
-   *  attachment. Decorative — lets the recipient card show the agent's avatar
-   *  without trusting sender-supplied identity. */
-  thumbUrl?: string;
 }): Promise<boolean> {
   const {
     encodeFn,
@@ -225,7 +221,6 @@ export async function runSendPipeline(deps: {
     buildMessageFn,
     checkEligibilityFn,
     channelId,
-    thumbUrl,
   } = deps;
 
   // ── Eligibility checkpoint 1: before encode ───────────────────────────────
@@ -284,13 +279,13 @@ export async function runSendPipeline(deps: {
   }
 
   // Preserve the original filename so `buildImetaTags` emits a `filename`
-  // field and the recipient's FileCard renders the correct label.
-  // Also carry the agent's avatar URL as the NIP-92 `thumb` field when
-  // the caller supplied one — decorative hint for the recipient card.
+  // field and the recipient's FileCard renders the correct label. Snapshot
+  // sends never emit `thumb`: NIP-92 requires it to be this upload's local
+  // thumbnail sidecar, which an agent avatar is not.
+  const { thumb: _thumb, ...descriptorWithoutThumb } = descriptor;
   const descriptorWithFilename: BlobDescriptor = {
-    ...descriptor,
+    ...descriptorWithoutThumb,
     filename: fileName,
-    ...(thumbUrl ? { thumb: thumbUrl } : {}),
   };
 
   // ── Build message content + NIP-92 imeta tags ─────────────────────────────
@@ -361,14 +356,10 @@ export type UseSnapshotSendControllerResult = {
    * false and sets error state if blocked, ineligible, or if any step fails.
    * Never throws.
    *
-   * @param thumbUrl Optional avatar URL emitted as the NIP-92 `thumb` imeta
-   *   field on the snapshot attachment — decorative, lets the recipient card
-   *   show the agent's avatar without any identity assertion.
    */
   beginSend: (
     encodeFn: () => Promise<{ fileBytes: number[]; fileName: string }>,
     channelId: string,
-    thumbUrl?: string,
   ) => Promise<boolean>;
   /** Set state to error with a message (for pre-send gate failures). */
   setErrorState: (message: string) => void;
@@ -461,12 +452,10 @@ export function useSnapshotSendController(): UseSnapshotSendControllerResult {
   async function beginSend(
     encodeFn: () => Promise<{ fileBytes: number[]; fileName: string }>,
     channelId: string,
-    thumbUrl?: string,
   ): Promise<boolean> {
     return runGuardedSend(guardRef.current, {
       encodeFn,
       channelId,
-      thumbUrl,
       // Eligibility is checked by reading directly from the React Query cache
       // and the timeout external store — not from rendered React state.
       checkEligibilityFn: () => checkSendEligibility(queryClient, channelId),

desktop/src/shared/ui/markdownFileCard.test.mjs

@@ -225,44 +225,7 @@ test("resolveSnapshotCard: uppercase .AGENT.JSON classifies as snapshot card", (
   assert.equal(card.sha256, SHA256);
 });
 
-// ── thumb plumbing ────────────────────────────────────────────────────────────
-
-test("resolveSnapshotCard: thumb field from imeta is forwarded for .agent.json", () => {
-  const thumbUrl = "https://relay.example/avatar.png";
-  const card = resolveSnapshotCard(
-    {
-      m: "application/json",
-      size: 500,
-      filename: "bot.agent.json",
-      x: SHA256,
-      thumb: thumbUrl,
-    },
-    JSON_URL,
-    "",
-  );
-  assert.ok(card !== null);
-  assert.equal(card.thumb, thumbUrl);
-});
-
-test("resolveSnapshotCard: relay-hosted JSON thumb is rewritten through media proxy", () => {
-  const thumbUrl = `https://relay.example/media/${"b".repeat(64)}.png`;
-  const card = resolveSnapshotCard(
-    {
-      m: "application/json",
-      size: 500,
-      filename: "bot.agent.json",
-      x: SHA256,
-      thumb: thumbUrl,
-    },
-    JSON_URL,
-    "",
-  );
-  assert.ok(card !== null);
-  assert.equal(
-    card.thumb,
-    `buzz-media://localhost/media/${"b".repeat(64)}.png`,
-  );
-});
+// ── snapshot card thumbnails ─────────────────────────────────────────────────
 
 test("resolveSnapshotCard: .agent.png uses its own URL as thumb", () => {
   const card = resolveSnapshotCard(

desktop/src/shared/ui/markdownFileCard.ts

@@ -86,14 +86,9 @@ export function resolveSnapshotCard(
     size: entry.size,
     sha256,
     snapshotKind: "agent",
-    // For PNG snapshots, use the attachment URL as the thumb source (it IS
-    // the avatar card image). For JSON, use the explicit imeta `thumb` field
-    // if the sender included one.
-    thumb: isPng
-      ? rewriteRelayUrl(href)
-      : entry.thumb
-        ? rewriteRelayUrl(entry.thumb)
-        : undefined,
+    // PNG snapshots use the attachment URL as the thumb source because it is
+    // the avatar card image. JSON snapshots use the generic icon.
+    thumb: isPng ? rewriteRelayUrl(href) : undefined,
   };
 }