diff --git a/CLAUDE.md b/CLAUDE.md
index 22da103..f8c4369 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -79,6 +79,9 @@ DynamoDB stores only sites, organisers, and registrations.
 `commands/github/invite_flow.py` contains the shared org-invite + team-add logic
 used by both the slash command (`add_member.py`) and the message shortcut
 (`add_member_shortcut.py`). Both pass a `reply` callback for message delivery.
+Channel replies are wrapped in `_safe_reply()` which catches exceptions; on
+failure, `_reply_or_dm()` falls back to DMing the caller. On success the caller
+always receives a DM confirmation as a failsafe.
 
 ### On-call rotation
 
@@ -111,7 +114,7 @@ members have been assigned in the current window, it cycles through again.
 - Two-tier permissions: `@core-team` Slack user group = global admin, site
   organisers = scoped to their hackathon site
 - All bot responses are ephemeral (only visible to the caller) unless explicitly
-  posting to a channel (e.g. `github add-member` posts visible thread replies)
+  posting to a channel (e.g. `github add` posts visible thread replies)
 - Form YAML supports `options_from: sites` for dynamic option lists populated
   from DynamoDB, and `options_from: countries` for type-ahead country search
 - GitHub API calls use a fine-grained PAT with `admin:org` scope
diff --git a/README.md b/README.md
index 40566b8..c42535b 100644
--- a/README.md
+++ b/README.md
@@ -9,27 +9,27 @@ AWS ECS Fargate + DynamoDB.
 This app adds two slash-commands which can be used by anyone in the nf-core
 slack.
 
-All responses are **ephemeral** (only visible to you), except
-`github add-member` which posts visible thread replies.
+All responses are **ephemeral** (only visible to you), except `github add` which
+posts visible thread replies.
 
 See [docs/commands.md](docs/commands.md) for the full command reference.
 
 ## General Automation
 
 ```bash
-/nf-core help                          # General help
-/nf-core github add-member @user       # Invite to nf-core GitHub org
-/nf-core github add-member <username>  # Invite by GitHub username
+/nf-core help                      # General help
+/nf-core github add @user          # Invite to nf-core GitHub org
+/nf-core github add <username>     # Invite by GitHub username
 ```
 
-The `github add-member` functionality works best when coming from the
+The `github add` functionality works best when coming from the
 `#github-invitations` channel: right-click any message → **More actions** →
 **Add to GitHub org** to invite the message author.
 
 This automatically finds the GitHub username from the Slack workflow message and
 sends them an invite, with membership in the _Collaborators_ team.
 
-The slach commands `/nf-core github add-member` are mostly for convenience when
+The slash commands `/nf-core github add` are mostly for convenience when
 replying elsewhere in Slack.
 
 ## Hackathon Registrations
diff --git a/docs/commands.md b/docs/commands.md
index e72c3a1..cb5c93f 100644
--- a/docs/commands.md
+++ b/docs/commands.md
@@ -285,10 +285,10 @@ These commands manage nf-core GitHub organisation membership. All require
 
 Show GitHub command help.
 
-### `github add-member`
+### `github add`
 
 ```
-/nf-core github add-member <@slack-user|github-username>
+/nf-core github add <@slack-user|github-username>
 ```
 
 Invite a user to the nf-core GitHub organisation and add them to the
@@ -304,8 +304,8 @@ Invite a user to the nf-core GitHub organisation and add them to the
 **Examples:**
 
 ```
-/nf-core github add-member @alice
-/nf-core github add-member octocat
+/nf-core github add @alice
+/nf-core github add octocat
 ```
 
 ### Message Shortcut: Add to GitHub org
@@ -319,7 +319,7 @@ threads).
 
 **Permissions:** `@core-team` only.
 
-### How `add-member` Works
+### How `add` Works
 
 1. **Permission check** — verifies you're in the `@core-team` Slack user group
 2. **Target resolution** — determines who to invite:
diff --git a/docs/slack-app-setup.md b/docs/slack-app-setup.md
index fbd0a24..844f817 100644
--- a/docs/slack-app-setup.md
+++ b/docs/slack-app-setup.md
@@ -44,7 +44,7 @@ public URL.
    - **Request URL:** `https://example.com/slack/events` (Socket Mode ignores
      this, but Slack requires a value)
    - **Short Description:** `nf-core community bot`
-   - **Usage Hint:** `[help | github add-member | hackathon register]`
+   - **Usage Hint:** `[help | github add | hackathon register]`
    - **Escape channels, users, and links sent to your app:** check this box
 4. Click **Save**
 
diff --git a/src/nf_core_bot/commands/github/add_member.py b/src/nf_core_bot/commands/github/add_member.py
index 9b3c686..9b44a5f 100644
--- a/src/nf_core_bot/commands/github/add_member.py
+++ b/src/nf_core_bot/commands/github/add_member.py
@@ -1,10 +1,10 @@
-"""``/nf-core github add-member`` — invite a user to the nf-core GitHub org.
+"""``/nf-core github add`` — invite a user to the nf-core GitHub org.
 
 Usage (explicit Slack mention):
-    ``/nf-core github add-member @slack-user``
+    ``/nf-core github add @slack-user``
 
 Usage (explicit GitHub username):
-    ``/nf-core github add-member octocat``
+    ``/nf-core github add octocat``
 
 To invite the author of a specific message, use the "Add to GitHub org"
 message shortcut (right-click a message → More actions) instead.
@@ -39,7 +39,7 @@ async def handle_add_member(
     command: dict[str, str],
     args: list[str],
 ) -> None:
-    """Handle ``/nf-core github add-member [target]``."""
+    """Handle ``/nf-core github add [target]``."""
     await ack()
 
     # ── 1. Permission check ──────────────────────────────────────────
@@ -66,7 +66,7 @@ async def handle_add_member(
             target_user_id = mention_match.group(1)
             github_username = await get_github_username(client, target_user_id)
             if github_username is None:
-                await _warn_missing_github(client, channel_id, thread_ts, target_user_id)
+                await _warn_missing_github(client, channel_id, thread_ts, target_user_id, respond)
                 return
         else:
             # Treat it as a plain GitHub username — validate first
@@ -81,7 +81,7 @@ async def handle_add_member(
     else:
         # No argument provided
         await respond(
-            "Usage: `/nf-core github add-member [@user | github-username]`\n\n"
+            "Usage: `/nf-core github add [@user | github-username]`\n\n"
             "You can also right-click a message and use *More actions → Add to GitHub org* "
             "to invite the message author.",
             response_type="ephemeral",
@@ -95,7 +95,7 @@ async def handle_add_member(
     async def _reply(text: str) -> None:
         await _thread_reply(client, channel_id, thread_ts, text)
 
-    await invite_and_greet(github_username, user_id, _reply, greeting_user_id=target_user_id)
+    await invite_and_greet(github_username, user_id, _reply, greeting_user_id=target_user_id, client=client)
 
 
 # ── Helpers ──────────────────────────────────────────────────────────
@@ -106,16 +106,25 @@ async def _warn_missing_github(
     channel_id: str,
     thread_ts: str,
     target_user_id: str,
+    respond: Respond | None = None,
 ) -> None:
-    """Post a visible thread reply telling the user to add their GitHub username."""
+    """Post a visible thread reply telling the user to add their GitHub username.
+
+    Falls back to an ephemeral *respond()* if the channel reply fails.
+    """
     text = (
         f"<@{target_user_id}> — please add your GitHub username to your Slack profile!\n"
         "Go to your profile → *Edit profile* → fill in the *GitHub* field.\n"
         "<https://slack.com/help/articles/204092246-Edit-your-profile|How to edit your Slack profile>\n\n"
         "Once done, a core-team member can re-run: "
-        "`/nf-core github add-member <github-username>`"
+        "`/nf-core github add <github-username>`"
     )
-    await _thread_reply(client, channel_id, thread_ts, text)
+    try:
+        await _thread_reply(client, channel_id, thread_ts, text)
+    except Exception:
+        logger.exception("Channel reply failed in _warn_missing_github")
+        if respond:
+            await respond(text, response_type="ephemeral")
 
 
 async def _thread_reply(
diff --git a/src/nf_core_bot/commands/github/add_member_shortcut.py b/src/nf_core_bot/commands/github/add_member_shortcut.py
index de447ed..c8f8c5b 100644
--- a/src/nf_core_bot/commands/github/add_member_shortcut.py
+++ b/src/nf_core_bot/commands/github/add_member_shortcut.py
@@ -102,9 +102,13 @@ async def handle_add_member_shortcut(
                 "Go to your profile → *Edit profile* → fill in the *GitHub* field.\n"
                 "<https://slack.com/help/articles/204092246-Edit-your-profile|How to edit your Slack profile>\n\n"
                 "Once done, a core-team member can try this action again, or use: "
-                "`/nf-core github add-member <github-username>`"
+                "`/nf-core github add <github-username>`"
             )
-            await client.chat_postMessage(channel=channel_id, thread_ts=thread_ts, text=text)
+            try:
+                await client.chat_postMessage(channel=channel_id, thread_ts=thread_ts, text=text)
+            except Exception:
+                logger.exception("Channel reply failed when warning about missing GitHub username")
+                await client.chat_postEphemeral(channel=channel_id, user=caller_id, text=text)
             return
     else:
         # Workflow/bot message — try to extract GitHub handle from the text
@@ -116,7 +120,7 @@ async def handle_add_member_shortcut(
                 user=caller_id,
                 text=(
                     "Couldn't find a GitHub username in this message.\n"
-                    "Use `/nf-core github add-member <github-username>` instead."
+                    "Use `/nf-core github add <github-username>` instead."
                 ),
             )
             return
@@ -131,4 +135,4 @@ async def handle_add_member_shortcut(
     async def _reply(text: str) -> None:
         await client.chat_postMessage(channel=channel_id, thread_ts=thread_ts, text=text)
 
-    await invite_and_greet(github_username, caller_id, _reply, greeting_user_id=greeting_user_id)
+    await invite_and_greet(github_username, caller_id, _reply, greeting_user_id=greeting_user_id, client=client)
diff --git a/src/nf_core_bot/commands/github/invite_flow.py b/src/nf_core_bot/commands/github/invite_flow.py
index b11fe33..088c0ff 100644
--- a/src/nf_core_bot/commands/github/invite_flow.py
+++ b/src/nf_core_bot/commands/github/invite_flow.py
@@ -10,53 +10,106 @@
 if TYPE_CHECKING:
     from collections.abc import Awaitable, Callable
 
+    from slack_sdk.web.async_client import AsyncWebClient
+
 logger = logging.getLogger(__name__)
 
 
+async def _safe_reply(reply: Callable[[str], Awaitable[None]], text: str) -> bool:
+    """Call *reply* and return ``True``.  If *reply* raises, log and return ``False``."""
+    try:
+        await reply(text)
+        return True
+    except Exception:
+        logger.exception("Channel reply failed")
+        return False
+
+
+async def _dm_caller(client: AsyncWebClient, caller_user_id: str, text: str) -> None:
+    """Send a DM to the person who triggered the command (best-effort)."""
+    try:
+        resp = await client.conversations_open(users=[caller_user_id])
+        dm_channel = resp["channel"]["id"]
+        await client.chat_postMessage(channel=dm_channel, text=text)
+    except Exception:
+        logger.exception("Failed to DM caller %s", caller_user_id)
+
+
+async def _reply_or_dm(
+    reply: Callable[[str], Awaitable[None]],
+    client: AsyncWebClient,
+    caller_user_id: str,
+    text: str,
+) -> None:
+    """Try the channel *reply*; fall back to a DM if it fails."""
+    if not await _safe_reply(reply, text):
+        await _dm_caller(client, caller_user_id, text)
+
+
 async def invite_and_greet(
     github_username: str,
     caller_user_id: str,
     reply: Callable[[str], Awaitable[None]],
     greeting_user_id: str | None = None,
+    *,
+    client: AsyncWebClient,
 ) -> bool:
     """Invite *github_username* to the nf-core org and contributors team.
 
     *reply* is called with message text for errors and the final greeting.
+    If *reply* raises (e.g. ``channel_not_found``), the error is logged and
+    the caller is notified via DM as a fallback.
+
     Returns ``True`` on success.
     """
+    # ── 1. Org invite ────────────────────────────────────────────────
     try:
         org_result = await invite_to_org(github_username)
     except Exception:
         logger.exception("Network error inviting %s to org", github_username)
-        await reply(f"Failed to reach the GitHub API while inviting `{github_username}`. Please try again later.")
+        msg = f"Failed to reach the GitHub API while inviting `{github_username}`. Please try again later."
+        await _reply_or_dm(reply, client, caller_user_id, msg)
         return False
 
     if not org_result.ok:
-        await reply(f"Failed to invite `{github_username}` to the nf-core GitHub org:\n>{org_result.message}")
+        msg = f"Failed to invite `{github_username}` to the nf-core GitHub org:\n>{org_result.message}"
+        await _reply_or_dm(reply, client, caller_user_id, msg)
         return False
 
+    # ── 2. Team add ──────────────────────────────────────────────────
     try:
         team_result = await add_to_team(github_username)
     except Exception:
         logger.exception("Network error adding %s to team", github_username)
-        await reply(
+        msg = (
             f"Invited `{github_username}` to the org, but failed to reach the GitHub API "
             "when adding to the contributors team. Please try again later."
         )
+        await _reply_or_dm(reply, client, caller_user_id, msg)
         return False
 
     if not team_result.ok:
-        await reply(
+        msg = (
             f"Invited `{github_username}` to the org, but failed to add to the "
             f"contributors team:\n>{team_result.message}"
         )
+        await _reply_or_dm(reply, client, caller_user_id, msg)
         return False
 
+    # ── 3. Success greeting ──────────────────────────────────────────
     greeting = f"Hi <@{greeting_user_id}>, " if greeting_user_id else f"Hi `{github_username}`, "
-    await reply(
+    msg = (
         f"{greeting}<@{caller_user_id}> has just added you to the nf-core GitHub organisation, "
         "welcome! :tada:\n\n"
         "You should have received an invite — you can either check your e-mail "
         "or click on this link to accept: https://github.com/orgs/nf-core/invitation"
     )
+    await _safe_reply(reply, msg)
+
+    # Always DM the caller as a failsafe confirmation
+    dm_text = (
+        f"Done! `{github_username}` has been invited to the nf-core GitHub org and added to the contributors team."
+    )
+    await _dm_caller(client, caller_user_id, dm_text)
+
     return True
diff --git a/src/nf_core_bot/commands/help.py b/src/nf_core_bot/commands/help.py
index b5058fe..c9ebee6 100644
--- a/src/nf_core_bot/commands/help.py
+++ b/src/nf_core_bot/commands/help.py
@@ -30,8 +30,8 @@
 ]
 
 GITHUB_COMMANDS: list[tuple[str, str, str]] = [
-    ("github add-member @user", "Invite a Slack user to nf-core GitHub org", "admin"),
-    ("github add-member <username>", "Invite a GitHub user to nf-core GitHub org", "admin"),
+    ("github add @user", "Invite a Slack user to nf-core GitHub org", "admin"),
+    ("github add <username>", "Invite a GitHub user to nf-core GitHub org", "admin"),
 ]
 
 ONCALL_COMMANDS: list[tuple[str, str, str]] = [
diff --git a/src/nf_core_bot/commands/router.py b/src/nf_core_bot/commands/router.py
index 109189b..ab1ec29 100644
--- a/src/nf_core_bot/commands/router.py
+++ b/src/nf_core_bot/commands/router.py
@@ -209,7 +209,7 @@ async def _route_admin(
 # ── GitHub dispatch ──────────────────────────────────────────────────
 
 _GITHUB_DISPATCH: dict[str, object] = {
-    "add-member": handle_add_member,
+    "add": handle_add_member,
 }
 
 
diff --git a/tests/helpers.py b/tests/helpers.py
new file mode 100644
index 0000000..ba01c5f
--- /dev/null
+++ b/tests/helpers.py
@@ -0,0 +1,27 @@
+"""Reusable test helpers for Slack client mocking."""
+
+from __future__ import annotations
+
+from unittest.mock import AsyncMock
+
+
+def make_slack_client() -> AsyncMock:
+    """Build an ``AsyncWebClient`` mock whose ``conversations_open`` returns a DM channel."""
+    client = AsyncMock()
+    client.conversations_open.return_value = {"channel": {"id": "D_DM"}}
+    return client
+
+
+def channel_messages(client: AsyncMock, channel: str = "C_CHAN") -> list[str]:
+    """Return all ``chat_postMessage`` texts sent to *channel*."""
+    texts: list[str] = []
+    for call in client.chat_postMessage.call_args_list:
+        ch = call.kwargs.get("channel", call.args[0] if call.args else "")
+        if ch == channel:
+            texts.append(call.kwargs.get("text", ""))
+    return texts
+
+
+def dm_messages(client: AsyncMock) -> list[str]:
+    """Return all ``chat_postMessage`` texts sent to the DM channel."""
+    return channel_messages(client, "D_DM")
diff --git a/tests/test_add_member.py b/tests/test_add_member.py
index cca9a64..2eca63b 100644
--- a/tests/test_add_member.py
+++ b/tests/test_add_member.py
@@ -6,6 +6,7 @@
 
 from nf_core_bot.checks.github import GitHubResult
 from nf_core_bot.commands.github.add_member import handle_add_member
+from tests.helpers import channel_messages, dm_messages, make_slack_client
 
 
 def _command(channel: str = "C_CHAN", thread_ts: str = "") -> dict[str, str]:
@@ -24,7 +25,7 @@ class TestPermissionGate:
     async def test_non_core_team_denied(self, _mock_perm: AsyncMock) -> None:
         ack = AsyncMock()
         respond = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member(ack, respond, client, "U_USER", _command(), ["octocat"])
 
@@ -46,26 +47,28 @@ async def test_valid_username_invites(self, mock_team: AsyncMock, mock_org: Asyn
 
         ack = AsyncMock()
         respond = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member(ack, respond, client, "U_ADMIN", _command(), ["octocat"])
 
         mock_org.assert_awaited_once_with("octocat")
         mock_team.assert_awaited_once_with("octocat")
-        # Final thread reply should mention success
-        client.chat_postMessage.assert_awaited()
-        final_text = client.chat_postMessage.call_args.kwargs.get(
-            "text", client.chat_postMessage.call_args[1].get("text", "")
-        )
-        assert "welcome" in final_text.lower()
-        assert "nf-core/invitation" in final_text
-        assert "<@U_ADMIN>" in final_text  # mentions who triggered it
+
+        # Channel reply should contain the welcome greeting
+        chan_texts = channel_messages(client)
+        assert any("welcome" in t.lower() for t in chan_texts)
+        assert any("nf-core/invitation" in t for t in chan_texts)
+        assert any("<@U_ADMIN>" in t for t in chan_texts)
+
+        # Caller should also get a DM confirmation
+        dm_texts = dm_messages(client)
+        assert any("octocat" in t for t in dm_texts)
 
     @patch("nf_core_bot.commands.github.add_member.is_core_team", return_value=True)
     async def test_invalid_username_rejected(self, _perm: AsyncMock) -> None:
         ack = AsyncMock()
         respond = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member(ack, respond, client, "U_ADMIN", _command(), ["I don't know"])
 
@@ -80,7 +83,7 @@ async def test_url_as_username_normalised(self, _perm: AsyncMock) -> None:
         """Passing a full GitHub URL should extract and validate the username."""
         ack = AsyncMock()
         respond = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         with (
             patch("nf_core_bot.commands.github.invite_flow.invite_to_org") as mock_org,
@@ -110,33 +113,35 @@ async def test_mention_resolves_github_username(
 
         ack = AsyncMock()
         respond = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member(ack, respond, client, "U_ADMIN", _command(), ["<@U01234TARGET>"])
 
         mock_ghuser.assert_awaited_once_with(client, "U01234TARGET")
         mock_org.assert_awaited_once_with("octocat")
-        # Success message should greet the target user by Slack mention
-        last_call = client.chat_postMessage.call_args_list[-1]
-        text = last_call.kwargs["text"]
-        assert "<@U01234TARGET>" in text  # greeting addresses the target
-        assert "<@U_ADMIN>" in text  # mentions who triggered it
+
+        # Channel reply should greet the target user
+        chan_texts = channel_messages(client)
+        assert any("<@U01234TARGET>" in t for t in chan_texts)
+        assert any("<@U_ADMIN>" in t for t in chan_texts)
+
+        # DM confirmation should be sent
+        dm_texts = dm_messages(client)
+        assert any("octocat" in t for t in dm_texts)
 
     @patch("nf_core_bot.commands.github.add_member.is_core_team", return_value=True)
     @patch("nf_core_bot.commands.github.add_member.get_github_username", return_value=None)
     async def test_mention_missing_github_warns(self, _mock_ghuser: AsyncMock, _perm: AsyncMock) -> None:
         ack = AsyncMock()
         respond = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member(ack, respond, client, "U_ADMIN", _command(thread_ts="123"), ["<@U01234TARGET>"])
 
         # Should post a warning about missing GitHub username
         client.chat_postMessage.assert_awaited()
-        text = client.chat_postMessage.call_args.kwargs.get(
-            "text", client.chat_postMessage.call_args[1].get("text", "")
-        )
-        assert "GitHub username" in text
+        chan_texts = channel_messages(client)
+        assert any("GitHub username" in t for t in chan_texts)
 
 
 # ── No-argument usage ────────────────────────────────────────────────
@@ -147,7 +152,7 @@ class TestNoArgs:
     async def test_no_args_shows_usage(self, _perm: AsyncMock) -> None:
         ack = AsyncMock()
         respond = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member(ack, respond, client, "U_ADMIN", _command(), [])
 
@@ -166,15 +171,12 @@ async def test_org_invite_network_error(self, mock_org: AsyncMock, _perm: AsyncM
 
         ack = AsyncMock()
         respond = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member(ack, respond, client, "U_ADMIN", _command(), ["octocat"])
 
-        client.chat_postMessage.assert_awaited()
-        text = client.chat_postMessage.call_args.kwargs.get(
-            "text", client.chat_postMessage.call_args[1].get("text", "")
-        )
-        assert "Failed to reach the GitHub API" in text
+        chan_texts = channel_messages(client)
+        assert any("Failed to reach the GitHub API" in t for t in chan_texts)
 
     @patch("nf_core_bot.commands.github.add_member.is_core_team", return_value=True)
     @patch("nf_core_bot.commands.github.invite_flow.invite_to_org")
@@ -183,15 +185,12 @@ async def test_org_invite_api_failure(self, mock_org: AsyncMock, _perm: AsyncMoc
 
         ack = AsyncMock()
         respond = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member(ack, respond, client, "U_ADMIN", _command(), ["octocat"])
 
-        client.chat_postMessage.assert_awaited()
-        text = client.chat_postMessage.call_args.kwargs.get(
-            "text", client.chat_postMessage.call_args[1].get("text", "")
-        )
-        assert "Failed to invite" in text
+        chan_texts = channel_messages(client)
+        assert any("Failed to invite" in t for t in chan_texts)
 
     @patch("nf_core_bot.commands.github.add_member.is_core_team", return_value=True)
     @patch("nf_core_bot.commands.github.invite_flow.invite_to_org")
@@ -202,15 +201,12 @@ async def test_team_add_network_error(self, mock_team: AsyncMock, mock_org: Asyn
 
         ack = AsyncMock()
         respond = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member(ack, respond, client, "U_ADMIN", _command(), ["octocat"])
 
-        client.chat_postMessage.assert_awaited()
-        text = client.chat_postMessage.call_args.kwargs.get(
-            "text", client.chat_postMessage.call_args[1].get("text", "")
-        )
-        assert "failed to reach the GitHub API" in text
+        chan_texts = channel_messages(client)
+        assert any("failed to reach the GitHub API" in t for t in chan_texts)
 
     @patch("nf_core_bot.commands.github.add_member.is_core_team", return_value=True)
     @patch("nf_core_bot.commands.github.invite_flow.invite_to_org")
@@ -221,12 +217,64 @@ async def test_team_add_api_failure(self, mock_team: AsyncMock, mock_org: AsyncM
 
         ack = AsyncMock()
         respond = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member(ack, respond, client, "U_ADMIN", _command(), ["octocat"])
 
-        client.chat_postMessage.assert_awaited()
-        text = client.chat_postMessage.call_args.kwargs.get(
-            "text", client.chat_postMessage.call_args[1].get("text", "")
-        )
-        assert "failed to add to the" in text
+        chan_texts = channel_messages(client)
+        assert any("failed to add to the" in t for t in chan_texts)
+
+
+# ── DM failsafe ──────────────────────────────────────────────────────
+
+
+class TestDmFailsafe:
+    @patch("nf_core_bot.commands.github.add_member.is_core_team", return_value=True)
+    @patch("nf_core_bot.commands.github.invite_flow.invite_to_org")
+    @patch("nf_core_bot.commands.github.invite_flow.add_to_team")
+    async def test_dm_sent_on_success(self, mock_team: AsyncMock, mock_org: AsyncMock, _perm: AsyncMock) -> None:
+        """Caller always receives a DM confirmation on success."""
+        mock_org.return_value = GitHubResult(ok=True, message="ok")
+        mock_team.return_value = GitHubResult(ok=True, message="ok")
+
+        ack = AsyncMock()
+        respond = AsyncMock()
+        client = make_slack_client()
+
+        await handle_add_member(ack, respond, client, "U_ADMIN", _command(), ["octocat"])
+
+        client.conversations_open.assert_awaited()
+        dm_texts = dm_messages(client)
+        assert any("octocat" in t and "invited" in t for t in dm_texts)
+
+    @patch("nf_core_bot.commands.github.add_member.is_core_team", return_value=True)
+    @patch("nf_core_bot.commands.github.invite_flow.invite_to_org")
+    @patch("nf_core_bot.commands.github.invite_flow.add_to_team")
+    async def test_dm_fallback_when_channel_reply_fails(
+        self, mock_team: AsyncMock, mock_org: AsyncMock, _perm: AsyncMock
+    ) -> None:
+        """When channel reply fails, caller gets the message via DM instead."""
+        mock_org.return_value = GitHubResult(ok=True, message="ok")
+        mock_team.return_value = GitHubResult(ok=True, message="ok")
+
+        ack = AsyncMock()
+        respond = AsyncMock()
+        client = make_slack_client()
+
+        # First chat_postMessage (channel reply) fails, subsequent ones (DMs) succeed
+        call_count = 0
+
+        async def _side_effect(**kwargs: str) -> dict:  # type: ignore[type-arg]
+            nonlocal call_count
+            call_count += 1
+            if call_count == 1:
+                raise RuntimeError("channel_not_found")
+            return {"ok": True}
+
+        client.chat_postMessage.side_effect = _side_effect
+
+        await handle_add_member(ack, respond, client, "U_ADMIN", _command(), ["octocat"])
+
+        # DM should still be sent
+        client.conversations_open.assert_awaited()
+        assert call_count >= 2  # channel reply failed + DM sent
diff --git a/tests/test_add_member_shortcut.py b/tests/test_add_member_shortcut.py
index 9f845cc..36beee6 100644
--- a/tests/test_add_member_shortcut.py
+++ b/tests/test_add_member_shortcut.py
@@ -10,6 +10,7 @@
     _extract_requester_from_text,
     handle_add_member_shortcut,
 )
+from tests.helpers import channel_messages, dm_messages, make_slack_client
 
 
 def _shortcut(
@@ -38,7 +39,7 @@ class TestPermissionGate:
     @patch("nf_core_bot.commands.github.add_member_shortcut.is_core_team", return_value=False)
     async def test_non_core_team_denied(self, _perm: AsyncMock) -> None:
         ack = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member_shortcut(ack, _shortcut(), client)
 
@@ -47,7 +48,8 @@ async def test_non_core_team_denied(self, _perm: AsyncMock) -> None:
         text = client.chat_postEphemeral.call_args.kwargs["text"]
         assert "restricted" in text.lower()
         # Should NOT proceed to GitHub calls
-        client.chat_postMessage.assert_not_awaited()
+        _chan = channel_messages(client)
+        assert not _chan
 
 
 # ── GitHub username resolution ───────────────────────────────────────
@@ -58,14 +60,13 @@ class TestGithubUsernameResolution:
     @patch("nf_core_bot.commands.github.add_member_shortcut.get_github_username", return_value=None)
     async def test_missing_github_warns(self, _ghuser: AsyncMock, _perm: AsyncMock) -> None:
         ack = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member_shortcut(ack, _shortcut(), client)
 
-        client.chat_postMessage.assert_awaited_once()
-        text = client.chat_postMessage.call_args.kwargs["text"]
-        assert "GitHub username" in text
-        assert "<@U_TARGET>" in text
+        chan_texts = channel_messages(client)
+        assert any("GitHub username" in t for t in chan_texts)
+        assert any("<@U_TARGET>" in t for t in chan_texts)
 
     @patch("nf_core_bot.commands.github.add_member_shortcut.is_core_team", return_value=True)
     @patch("nf_core_bot.commands.github.add_member_shortcut.get_github_username", return_value="octocat")
@@ -78,19 +79,23 @@ async def test_success_invites_and_adds(
         mock_team.return_value = GitHubResult(ok=True, message="active")
 
         ack = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member_shortcut(ack, _shortcut(), client)
 
         mock_org.assert_awaited_once_with("octocat")
         mock_team.assert_awaited_once_with("octocat")
-        # Final message should be a welcome with invite link
-        last_call = client.chat_postMessage.call_args_list[-1]
-        text = last_call.kwargs["text"]
-        assert "welcome" in text.lower()
-        assert "nf-core/invitation" in text
-        assert "<@U_TARGET>" in text  # greeting addresses the message author
-        assert "<@U_ADMIN>" in text  # mentions who triggered it
+
+        # Channel reply should be a welcome with invite link
+        chan_texts = channel_messages(client)
+        assert any("welcome" in t.lower() for t in chan_texts)
+        assert any("nf-core/invitation" in t for t in chan_texts)
+        assert any("<@U_TARGET>" in t for t in chan_texts)  # greeting addresses the message author
+        assert any("<@U_ADMIN>" in t for t in chan_texts)  # mentions who triggered it
+
+        # Caller should also get a DM confirmation
+        dm_texts = dm_messages(client)
+        assert any("octocat" in t for t in dm_texts)
 
 
 # ── Thread reply placement ───────────────────────────────────────────
@@ -108,14 +113,16 @@ async def test_replies_in_thread_when_in_thread(
         mock_team.return_value = GitHubResult(ok=True, message="ok")
 
         ack = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         sc = _shortcut(message_ts="222.333", thread_ts="111.000")
         await handle_add_member_shortcut(ack, sc, client)
 
-        # Should reply in the parent thread, not the message itself
-        last_call = client.chat_postMessage.call_args_list[-1]
-        assert last_call.kwargs["thread_ts"] == "111.000"
+        # The greeting (channel reply) should be in the parent thread, not the message itself
+        chan_calls = [c for c in client.chat_postMessage.call_args_list if c.kwargs.get("channel") == "C_CHAN"]
+        greeting_call = [c for c in chan_calls if "welcome" in c.kwargs.get("text", "").lower()]
+        assert greeting_call
+        assert greeting_call[0].kwargs["thread_ts"] == "111.000"
 
     @patch("nf_core_bot.commands.github.add_member_shortcut.is_core_team", return_value=True)
     @patch("nf_core_bot.commands.github.add_member_shortcut.get_github_username", return_value="octocat")
@@ -128,14 +135,16 @@ async def test_replies_to_message_when_not_in_thread(
         mock_team.return_value = GitHubResult(ok=True, message="ok")
 
         ack = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         sc = _shortcut(message_ts="222.333")
         await handle_add_member_shortcut(ack, sc, client)
 
-        # Should reply to the message itself (creating a thread)
-        last_call = client.chat_postMessage.call_args_list[-1]
-        assert last_call.kwargs["thread_ts"] == "222.333"
+        # The greeting should reply to the message itself (creating a thread)
+        chan_calls = [c for c in client.chat_postMessage.call_args_list if c.kwargs.get("channel") == "C_CHAN"]
+        greeting_call = [c for c in chan_calls if "welcome" in c.kwargs.get("text", "").lower()]
+        assert greeting_call
+        assert greeting_call[0].kwargs["thread_ts"] == "222.333"
 
 
 # ── Workflow / bot message handling ───────────────────────────────────
@@ -223,24 +232,28 @@ async def test_workflow_message_extracts_handle(
         mock_team.return_value = GitHubResult(ok=True, message="ok")
 
         ack = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         sc = _workflow_shortcut("By <@U0REQUESTER> at March 13th, 2026\n*Which is your GitHub handle?*\nMuteebaAzhar")
         await handle_add_member_shortcut(ack, sc, client)
 
         mock_org.assert_awaited_once_with("MuteebaAzhar")
         mock_team.assert_awaited_once_with("MuteebaAzhar")
-        # Welcome message should mention the requester and the caller
-        last_call = client.chat_postMessage.call_args_list[-1]
-        text = last_call.kwargs["text"]
-        assert "<@U0REQUESTER>" in text  # greeting addresses workflow requester
-        assert "<@U_ADMIN>" in text  # mentions who triggered it
-        assert "nf-core/invitation" in text
+
+        # Channel reply should mention the requester and the caller
+        chan_texts = channel_messages(client)
+        assert any("<@U0REQUESTER>" in t for t in chan_texts)  # greeting addresses workflow requester
+        assert any("<@U_ADMIN>" in t for t in chan_texts)  # mentions who triggered it
+        assert any("nf-core/invitation" in t for t in chan_texts)
+
+        # DM confirmation should be sent
+        dm_texts = dm_messages(client)
+        assert any("MuteebaAzhar" in t for t in dm_texts)
 
     @patch("nf_core_bot.commands.github.add_member_shortcut.is_core_team", return_value=True)
     async def test_workflow_message_no_handle_shows_error(self, _perm: AsyncMock) -> None:
         ack = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         sc = _workflow_shortcut("Just a random bot message")
         await handle_add_member_shortcut(ack, sc, client)
@@ -261,12 +274,15 @@ async def test_org_invite_network_error(self, mock_org: AsyncMock, _ghuser: Asyn
         mock_org.side_effect = RuntimeError("connection refused")
 
         ack = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member_shortcut(ack, _shortcut(), client)
 
-        last_msg = client.chat_postMessage.call_args_list[-1]
-        assert "Failed to reach the GitHub API" in last_msg.kwargs["text"]
+        chan_texts = channel_messages(client)
+        # Channel reply may or may not work — check DM too
+        dm_texts = dm_messages(client)
+        all_texts = chan_texts + dm_texts
+        assert any("Failed to reach the GitHub API" in t for t in all_texts)
 
     @patch("nf_core_bot.commands.github.add_member_shortcut.is_core_team", return_value=True)
     @patch("nf_core_bot.commands.github.add_member_shortcut.get_github_username", return_value="octocat")
@@ -275,12 +291,14 @@ async def test_org_invite_api_failure(self, mock_org: AsyncMock, _ghuser: AsyncM
         mock_org.return_value = GitHubResult(ok=False, message="422 — Validation failed")
 
         ack = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
 
         await handle_add_member_shortcut(ack, _shortcut(), client)
 
-        last_msg = client.chat_postMessage.call_args_list[-1]
-        assert "Failed to invite" in last_msg.kwargs["text"]
+        chan_texts = channel_messages(client)
+        dm_texts = dm_messages(client)
+        all_texts = chan_texts + dm_texts
+        assert any("Failed to invite" in t for t in all_texts)
 
     @patch("nf_core_bot.commands.github.add_member_shortcut.is_core_team", return_value=True)
     @patch("nf_core_bot.commands.github.add_member_shortcut.get_github_username", return_value="octocat")
@@ -293,9 +311,68 @@ async def test_team_add_network_error(
         mock_team.side_effect = RuntimeError("timeout")
 
         ack = AsyncMock()
-        client = AsyncMock()
+        client = make_slack_client()
+
+        await handle_add_member_shortcut(ack, _shortcut(), client)
+
+        chan_texts = channel_messages(client)
+        dm_texts = dm_messages(client)
+        all_texts = chan_texts + dm_texts
+        assert any("failed to reach the GitHub API" in t for t in all_texts)
+
+
+# ── DM failsafe ──────────────────────────────────────────────────────
+
+
+class TestDmFailsafe:
+    @patch("nf_core_bot.commands.github.add_member_shortcut.is_core_team", return_value=True)
+    @patch("nf_core_bot.commands.github.add_member_shortcut.get_github_username", return_value="octocat")
+    @patch("nf_core_bot.commands.github.invite_flow.invite_to_org")
+    @patch("nf_core_bot.commands.github.invite_flow.add_to_team")
+    async def test_dm_sent_on_success(
+        self, mock_team: AsyncMock, mock_org: AsyncMock, _ghuser: AsyncMock, _perm: AsyncMock
+    ) -> None:
+        """Caller always receives a DM confirmation on success."""
+        mock_org.return_value = GitHubResult(ok=True, message="ok")
+        mock_team.return_value = GitHubResult(ok=True, message="ok")
+
+        ack = AsyncMock()
+        client = make_slack_client()
+
+        await handle_add_member_shortcut(ack, _shortcut(), client)
+
+        client.conversations_open.assert_awaited()
+        dm_texts = dm_messages(client)
+        assert any("octocat" in t and "invited" in t for t in dm_texts)
+
+    @patch("nf_core_bot.commands.github.add_member_shortcut.is_core_team", return_value=True)
+    @patch("nf_core_bot.commands.github.add_member_shortcut.get_github_username", return_value="octocat")
+    @patch("nf_core_bot.commands.github.invite_flow.invite_to_org")
+    @patch("nf_core_bot.commands.github.invite_flow.add_to_team")
+    async def test_channel_reply_failure_falls_back_to_dm(
+        self, mock_team: AsyncMock, mock_org: AsyncMock, _ghuser: AsyncMock, _perm: AsyncMock
+    ) -> None:
+        """When channel reply fails, caller still gets the DM."""
+        mock_org.return_value = GitHubResult(ok=True, message="ok")
+        mock_team.return_value = GitHubResult(ok=True, message="ok")
+
+        ack = AsyncMock()
+        client = make_slack_client()
+
+        # First chat_postMessage (channel reply) fails, subsequent ones (DMs) succeed
+        call_count = 0
+
+        async def _side_effect(**kwargs: str) -> dict:  # type: ignore[type-arg]
+            nonlocal call_count
+            call_count += 1
+            if call_count == 1:
+                raise RuntimeError("channel_not_found")
+            return {"ok": True}
+
+        client.chat_postMessage.side_effect = _side_effect
 
         await handle_add_member_shortcut(ack, _shortcut(), client)
 
-        last_msg = client.chat_postMessage.call_args_list[-1]
-        assert "failed to reach the GitHub API" in last_msg.kwargs["text"]
+        # DM should still be sent
+        client.conversations_open.assert_awaited()
+        assert call_count >= 2
diff --git a/tests/test_router_integration.py b/tests/test_router_integration.py
index c933f20..8e8ea7e 100644
--- a/tests/test_router_integration.py
+++ b/tests/test_router_integration.py
@@ -180,8 +180,8 @@ async def test_export_receives_ack_respond_client_body_rest(self, monkeypatch):
 class TestGithubDispatchTypes:
     async def test_add_member_receives_correct_args(self, monkeypatch):
         mock = AsyncMock()
-        monkeypatch.setitem(router_mod._GITHUB_DISPATCH, "add-member", mock)
-        await dispatch(AsyncMock(), AsyncMock(), AsyncMock(), _command("github add-member octocat"))
+        monkeypatch.setitem(router_mod._GITHUB_DISPATCH, "add", mock)
+        await dispatch(AsyncMock(), AsyncMock(), AsyncMock(), _command("github add octocat"))
         mock.assert_awaited_once()
         args = mock.call_args[0]
         assert len(args) == 6  # ack, respond, client, user_id, command, rest