Be more forgiving around hashtag channel names

AGENTS.md

@@ -422,6 +422,7 @@ All endpoints are prefixed with `/api` (e.g., `/api/health`).
 
 - Stored as 32-character hex string (TEXT PRIMARY KEY)
 - Hashtag channels: `SHA256("#name")[:16]` converted to hex
+- Hashtag channel names are hashed **verbatim** (any character — `&`, capitals, spaces, accents — is valid), matching `meshcore_py` / meshcore-cli / meshcore.js, which impose no character restriction (firmware never validates or even sees the name; it only receives the precomputed secret). The New-Conversation UI defaults to normalizing names to lowercase `[a-z0-9-]`, but a "Permit capitals, whitespace, and extended characters" toggle hashes the name exactly as typed for cross-client interop. The only server-side limit is non-empty and ≤32 UTF-8 bytes including the leading `#` (the on-radio name field size).
 - Custom channels: User-provided or generated
 - Channels may also persist `flood_scope_override`; when set, channel sends temporarily switch the radio flood scope to that value for the duration of the send, then restore the global app setting.
 - Channels may persist `path_hash_mode_override` (0/1/2); when set, channel sends temporarily switch the radio path hash mode for the duration of the send, then restore the radio default.

app/routers/channels.py

@@ -1,5 +1,4 @@
 import logging
-import re
 from hashlib import sha256
 
 from fastapi import APIRouter, BackgroundTasks, HTTPException, Response, status
@@ -121,9 +120,13 @@ def _normalize_bulk_hashtag_name(name: str) -> str | None:
     normalized = trimmed.lstrip("#").strip()
     if not normalized:
         return None
-    if len(normalized) > 31:
-        return None
-    if not re.fullmatch(r"[A-Za-z0-9]+(?:-[A-Za-z0-9]+)*", normalized):
+    # Hashtag channel names are hashed verbatim (matching meshcore_py / meshcore-cli /
+    # meshcore.js), so any character is permitted — '&', capitals, accents, etc. all map
+    # to a valid SHA256-derived key. Character normalization (lowercasing / charset
+    # restriction) is a client-side display choice, applied by the caller before submit.
+    # The on-radio name field holds 32 UTF-8 bytes including the leading '#', so cap there
+    # to keep the stored label and the derived key in sync across clients.
+    if len(f"#{normalized}".encode()) > 32:
         return None
     return f"#{normalized}"
 

frontend/src/components/NewMessageModal.tsx

@@ -43,19 +43,30 @@ interface NewMessageModalProps {
   onBulkAddHashtagChannels: (channelNames: string[], tryHistorical: boolean) => Promise<void>;
 }
 
-function validateHashtagName(channelName: string): string | null {
+function validateHashtagName(channelName: string, permitExtended: boolean): string | null {
   if (!channelName) {
     return 'Channel name is required';
   }
+  // The on-radio channel name field holds 32 UTF-8 bytes including the leading '#'.
+  if (new TextEncoder().encode(`#${channelName}`).length > 32) {
+    return 'Channel name is too long (max 32 bytes including #)';
+  }
+  if (permitExtended) {
+    // Hashed verbatim, matching meshcore_py / meshcore-cli / meshcore.js — any character
+    // (capitals, whitespace, '&', accents, …) yields a valid SHA256-derived key.
+    return null;
+  }
   if (!/^[a-zA-Z0-9]+(-[a-zA-Z0-9]+)*$/.test(channelName)) {
     return 'Use letters, numbers, and single dashes (no leading/trailing dashes)';
   }
   return null;
 }
 
-function parseBulkHashtagNames(rawText: string, permitCapitals: boolean): BulkParseResult {
+function parseBulkHashtagNames(rawText: string, permitExtended: boolean): BulkParseResult {
+  // When extended names are permitted, whitespace can be part of a name, so split on
+  // newlines/commas only. Otherwise keep the whitespace-delimited behavior.
   const tokens = rawText
-    .split(/[\s,]+/)
+    .split(permitExtended ? /[\n,]+/ : /[\s,]+/)
     .map((token) => token.trim())
     .filter(Boolean);
 
@@ -65,13 +76,13 @@ function parseBulkHashtagNames(rawText: string, permitCapitals: boolean): BulkPa
 
   for (const token of tokens) {
     const stripped = token.replace(/^#+/, '');
-    const validationError = validateHashtagName(stripped);
+    const validationError = validateHashtagName(stripped, permitExtended);
     if (validationError) {
       invalidNames.push(token);
       continue;
     }
 
-    const normalized = permitCapitals ? stripped : stripped.toLowerCase();
+    const normalized = permitExtended ? stripped : stripped.toLowerCase();
     const channelName = `#${normalized}`;
     if (seen.has(channelName)) {
       continue;
@@ -101,7 +112,7 @@ export function NewMessageModal({
   const [channelKey, setChannelKey] = useState('');
   const [bulkChannelText, setBulkChannelText] = useState('');
   const [tryHistorical, setTryHistorical] = useState(false);
-  const [permitCapitals, setPermitCapitals] = useState(false);
+  const [permitExtended, setPermitExtended] = useState(false);
   const [error, setError] = useState('');
   const [loading, setLoading] = useState(false);
   const hashtagInputRef = useRef<HTMLInputElement>(null);
@@ -114,7 +125,7 @@ export function NewMessageModal({
     setChannelKey('');
     setBulkChannelText('');
     setTryHistorical(false);
-    setPermitCapitals(false);
+    setPermitExtended(false);
     setError('');
   };
 
@@ -130,7 +141,7 @@ export function NewMessageModal({
       setChannelKey('');
       setBulkChannelText('');
       setTryHistorical(false);
-      setPermitCapitals(false);
+      setPermitExtended(false);
       setError('');
       setLoading(false);
       requestAnimationFrame(() => {
@@ -146,7 +157,7 @@ export function NewMessageModal({
       setChannelKey('');
       setBulkChannelText('');
       setTryHistorical(false);
-      setPermitCapitals(false);
+      setPermitExtended(false);
       setError('');
       setLoading(false);
       requestAnimationFrame(() => {
@@ -177,17 +188,17 @@ export function NewMessageModal({
         await onCreateChannel(name.trim(), channelKey.trim(), tryHistorical);
       } else if (tab === 'hashtag') {
         const channelName = name.trim();
-        const validationError = validateHashtagName(channelName);
+        const validationError = validateHashtagName(channelName, permitExtended);
         if (validationError) {
           setError(validationError);
           return;
         }
-        const normalizedName = permitCapitals ? channelName : channelName.toLowerCase();
+        const normalizedName = permitExtended ? channelName : channelName.toLowerCase();
         await onCreateHashtagChannel(`#${normalizedName}`, tryHistorical);
       } else {
         const { channelNames, invalidNames } = parseBulkHashtagNames(
           bulkChannelText,
-          permitCapitals
+          permitExtended
         );
         if (channelNames.length === 0) {
           setError('Enter at least one valid channel name');
@@ -215,7 +226,7 @@ export function NewMessageModal({
   const handleCreateAndAddAnother = async () => {
     setError('');
     const channelName = name.trim();
-    const validationError = validateHashtagName(channelName);
+    const validationError = validateHashtagName(channelName, permitExtended);
     if (validationError) {
       setError(validationError);
       return;
@@ -223,7 +234,7 @@ export function NewMessageModal({
 
     setLoading(true);
     try {
-      const normalizedName = permitCapitals ? channelName : channelName.toLowerCase();
+      const normalizedName = permitExtended ? channelName : channelName.toLowerCase();
       await onCreateHashtagChannel(`#${normalizedName}`, tryHistorical);
       setName('');
       hashtagInputRef.current?.focus();
@@ -375,14 +386,18 @@ export function NewMessageModal({
               <label className="flex cursor-pointer items-center gap-3">
                 <input
                   type="checkbox"
-                  checked={permitCapitals}
-                  onChange={(e) => setPermitCapitals(e.target.checked)}
+                  checked={permitExtended}
+                  onChange={(e) => setPermitExtended(e.target.checked)}
                   className="h-4 w-4 rounded border-input accent-primary"
                 />
-                <span className="text-sm">Permit capitals in channel key derivation</span>
+                <span className="text-sm">
+                  Permit capitals, whitespace, and extended characters
+                </span>
               </label>
               <p className="pl-7 text-xs text-muted-foreground">
-                Not recommended; most companions normalize to lowercase
+                Off normalizes to lowercase letters, numbers, and dashes. On hashes the name exactly
+                as typed — matches other MeshCore clients and lets you join channels with capitals,
+                spaces, or symbols like &amp;.
               </p>
             </div>
           </TabsContent>
@@ -401,22 +416,27 @@ export function NewMessageModal({
                   className="min-h-48 w-full rounded-md border border-input bg-background px-3 py-2 text-sm shadow-sm outline-none transition-colors placeholder:text-muted-foreground focus-visible:ring-2 focus-visible:ring-ring"
                 />
                 <p className="text-xs text-muted-foreground">
-                  Paste channel names separated by lines, spaces, or commas. Leading # marks are
-                  stripped automatically.
+                  {permitExtended
+                    ? 'One channel name per line (or comma-separated); spaces are kept as part of the name. Leading # marks are stripped automatically.'
+                    : 'Paste channel names separated by lines, spaces, or commas. Leading # marks are stripped automatically.'}
                 </p>
               </div>
               <div className="space-y-1">
                 <label className="flex cursor-pointer items-center gap-3">
                   <input
                     type="checkbox"
-                    checked={permitCapitals}
-                    onChange={(e) => setPermitCapitals(e.target.checked)}
+                    checked={permitExtended}
+                    onChange={(e) => setPermitExtended(e.target.checked)}
                     className="h-4 w-4 rounded border-input accent-primary"
                   />
-                  <span className="text-sm">Permit capitals in channel key derivation</span>
+                  <span className="text-sm">
+                    Permit capitals, whitespace, and extended characters
+                  </span>
                 </label>
                 <p className="pl-7 text-xs text-muted-foreground">
-                  Not recommended; most companions normalize to lowercase
+                  Off normalizes to lowercase letters, numbers, and dashes. On hashes each name
+                  exactly as typed — matches other MeshCore clients and lets you join channels with
+                  capitals, spaces, or symbols like &amp;.
                 </p>
               </div>
             </TabsContent>

frontend/src/test/newMessageModal.test.tsx

@@ -111,6 +111,38 @@ describe('NewMessageModal form reset', () => {
       await user.click(screen.getByRole('button', { name: 'Cancel' }));
       expect(onClose).toHaveBeenCalled();
     });
+
+    it('rejects extended characters when the extended toggle is off', async () => {
+      const user = userEvent.setup();
+      renderModal();
+      await switchToTab(user, 'Hashtag Channel');
+
+      await user.type(screen.getByPlaceholderText('channel-name'), 'Cats&Dogs');
+      await user.click(screen.getByRole('button', { name: 'Create' }));
+
+      expect(onCreateHashtagChannel).not.toHaveBeenCalled();
+      expect(
+        screen.getByText('Use letters, numbers, and single dashes (no leading/trailing dashes)')
+      ).toBeTruthy();
+    });
+
+    it('hashes the name verbatim when the extended toggle is on', async () => {
+      const user = userEvent.setup();
+      renderModal();
+      await switchToTab(user, 'Hashtag Channel');
+
+      await user.click(
+        screen.getByRole('checkbox', {
+          name: /Permit capitals, whitespace, and extended characters/,
+        })
+      );
+      await user.type(screen.getByPlaceholderText('channel-name'), 'Cats&Dogs');
+      await user.click(screen.getByRole('button', { name: 'Create' }));
+
+      await waitFor(() => {
+        expect(onCreateHashtagChannel).toHaveBeenCalledWith('#Cats&Dogs', false);
+      });
+    });
   });
 
   describe('bulk hashtag tab', () => {
@@ -158,6 +190,29 @@ describe('NewMessageModal form reset', () => {
       expect(onBulkAddHashtagChannels).not.toHaveBeenCalled();
       expect(screen.getByText('Invalid channel names: bad_room')).toBeTruthy();
     });
+
+    it('accepts extended names split by lines when the toggle is on', async () => {
+      const user = userEvent.setup();
+      renderModal(true, { showBulkAddChannelTab: true });
+
+      await user.click(
+        screen.getByRole('checkbox', {
+          name: /Permit capitals, whitespace, and extended characters/,
+        })
+      );
+      await user.type(
+        screen.getByRole('textbox', { name: 'Bulk channel names' }),
+        '#Cats & Dogs{enter}Mesh Room'
+      );
+      await user.click(screen.getByRole('button', { name: 'Add Channels' }));
+
+      await waitFor(() => {
+        expect(onBulkAddHashtagChannels).toHaveBeenCalledWith(
+          ['#Cats & Dogs', '#Mesh Room'],
+          false
+        );
+      });
+    });
   });
 
   describe('new-contact tab', () => {

tests/test_channels_router.py

@@ -83,10 +83,19 @@ class TestCreateChannel:
         ops_key = sha256(b"#ops").digest()[:16].hex().upper()
         await ChannelRepository.upsert(key=ops_key, name="#ops", is_hashtag=True)
 
+        # Names are hashed verbatim, so extended characters (e.g. '&') and underscores are
+        # valid; only empty/whitespace-only or over-long names are rejected server-side.
         response = await client.post(
             "/api/channels/bulk-hashtag",
             json={
-                "channel_names": ["#ops", "mesh-room", "bad_room", "mesh-room", "another-room"],
+                "channel_names": [
+                    "#ops",
+                    "mesh-room",
+                    "cats&dogs",
+                    "mesh-room",
+                    "   ",
+                    "another-room",
+                ],
                 "try_historical": False,
             },
         )
@@ -95,10 +104,11 @@ class TestCreateChannel:
         data = response.json()
         assert [channel["name"] for channel in data["created_channels"]] == [
             "#mesh-room",
+            "#cats&dogs",
             "#another-room",
         ]
         assert data["existing_count"] == 2
-        assert data["invalid_names"] == ["bad_room"]
+        assert data["invalid_names"] == ["   "]
         assert data["decrypt_started"] is False
 
     @pytest.mark.asyncio