Add proper p tags for replies and mentions

src/lib/components/MessageEditor.svelte

@@ -105,6 +105,17 @@
     textareaEl?.focus();
   }
 
+  // Warm the kind:10002 cache for thread participants so relay hints are
+  // ready by publish time. Best-effort, dedup across focus events.
+  const prefetched = new Set<string>();
+  function onTextareaFocus() {
+    for (const pk of contextPubkeys) {
+      if (prefetched.has(pk)) continue;
+      prefetched.add(pk);
+      loadRelayList(pk).catch(() => {});
+    }
+  }
+
   function togglePreview() {
     previewing = !previewing;
   }
@@ -334,6 +345,7 @@
         onkeydown={onTextareaKeydown}
         onclick={onTextareaClickOrSelect}
         onkeyup={onTextareaClickOrSelect}
+        onfocus={onTextareaFocus}
         onblur={onTextareaBlur}
         aria-autocomplete="list"
         aria-controls={mentionOpen ? "mention-listbox" : undefined}

src/lib/draft.svelte.ts

@@ -2,6 +2,7 @@ import { SimplePool } from "@nostr/tools";
 import { auth } from "$lib/auth.svelte";
 import { withJoin } from "$lib/join.svelte";
 import { GROUP_ID, RELAY_URL } from "$lib/config";
+import { extractMentionPubkeys, buildPTagHints } from "$lib/mentions";
 
 let modalOpen = $state(false);
 let iconized = $state(false);
@@ -80,6 +81,10 @@ export async function publishDraft(): Promise<{ ok: boolean; threadId?: string }
   publishError = null;
   let threadId: string | undefined;
 
+  const ownPubkey = auth.user?.pubkey;
+  const mentionPubkeys = extractMentionPubkeys(c).filter((pk) => pk !== ownPubkey);
+  const hints = await buildPTagHints(mentionPubkeys);
+
   try {
     const success = await withJoin(async () => {
       const tags: string[][] = [
@@ -87,6 +92,10 @@ export async function publishDraft(): Promise<{ ok: boolean; threadId?: string }
         ["title", t],
       ];
       for (const l of labels) tags.push(["t", l]);
+      for (const pk of mentionPubkeys) {
+        const hint = hints.get(pk);
+        tags.push(hint ? ["p", pk, hint] : ["p", pk]);
+      }
 
       const event = await auth.signer!.signEvent({
         kind: 11,

src/lib/mentions.ts

@@ -0,0 +1,46 @@
+import * as nip19 from "@nostr/tools/nip19";
+import { loadRelayList } from "@nostr/gadgets/lists";
+
+const RELAY_HINT_TIMEOUT_MS = 1500;
+
+export function extractMentionPubkeys(content: string): string[] {
+  const re = /nostr:(npub1[a-z0-9]+|nprofile1[a-z0-9]+)/gi;
+  const out = new Set<string>();
+  for (const m of content.matchAll(re)) {
+    try {
+      const decoded = nip19.decode(m[1]);
+      if (decoded.type === "npub") out.add(decoded.data);
+      else if (decoded.type === "nprofile") out.add(decoded.data.pubkey);
+    } catch {
+      // Invalid bech32, skip
+    }
+  }
+  return [...out];
+}
+
+export async function relayHintFor(pubkey: string): Promise<string | undefined> {
+  try {
+    const TIMEOUT = Symbol();
+    const result = await Promise.race([
+      loadRelayList(pubkey),
+      new Promise<typeof TIMEOUT>((resolve) =>
+        setTimeout(() => resolve(TIMEOUT), RELAY_HINT_TIMEOUT_MS),
+      ),
+    ]);
+    if (result === TIMEOUT) return undefined;
+    return result.items.find((r) => r.write)?.url;
+  } catch {
+    return undefined;
+  }
+}
+
+export async function buildPTagHints(pubkeys: Iterable<string>): Promise<Map<string, string>> {
+  const hints = new Map<string, string>();
+  await Promise.all(
+    [...pubkeys].map(async (pk) => {
+      const url = await relayHintFor(pk);
+      if (url) hints.set(pk, url);
+    }),
+  );
+  return hints;
+}

src/lib/thread.svelte.ts

@@ -4,6 +4,7 @@ import { RELAY_URL, GROUP_ID } from "$lib/config";
 import { threads as mockThreads } from "$lib/mock";
 import { auth } from "$lib/auth.svelte";
 import { ingestNostrUser } from "$lib/profiles.svelte";
+import { extractMentionPubkeys, buildPTagHints } from "$lib/mentions";
 
 const isNostrId = (id: string) => /^[0-9a-f]{64}$/.test(id);
 
@@ -112,11 +113,31 @@ export async function sendReply(content: string, ownPubkey: string) {
     .slice(-3)
     .map((p) => p.id.slice(0, 8));
 
+  // NIP-7D mandates flat-against-root, so parent === root for every reply.
+  // Build the notify set: thread participants + mentions in content, minus self.
+  const notifyPubkeys = new Set<string>();
+  notifyPubkeys.add(detail.op.pubkey);
+  for (const r of detail.replies) notifyPubkeys.add(r.pubkey);
+  for (const pk of extractMentionPubkeys(content)) notifyPubkeys.add(pk);
+  notifyPubkeys.delete(ownPubkey);
+
+  // Best-effort relay hints — cached calls return instantly, others race a timeout.
+  const hints = await buildPTagHints([...notifyPubkeys, detail.op.pubkey]);
+
+  const opHint = hints.get(detail.op.pubkey) ?? RELAY_URL;
+
   const tags: string[][] = [
     ["h", GROUP_ID],
+    ["E", detail.id, opHint, detail.op.pubkey],
     ["K", "11"],
-    ["E", detail.id, RELAY_URL, detail.op.pubkey],
+    ["P", detail.op.pubkey, opHint],
+    ["e", detail.id, opHint, detail.op.pubkey],
+    ["k", "11"],
   ];
+  for (const pk of notifyPubkeys) {
+    const hint = hints.get(pk);
+    tags.push(hint ? ["p", pk, hint] : ["p", pk]);
+  }
   if (previousRefs.length > 0) tags.push(["previous", ...previousRefs]);
 
   console.log("[reply] signing event…");