Messaging & Commands

Message Handling

Aspect	Slack	Teams
Handler	app.message(pattern, handler)	app.on("message", handler)
Pattern matching	String (substring), RegExp, or catch-all	RegExp or manual text.match()
Reply to channel	say(text)	ctx.send(text)
Reply in thread	say(\{ text, thread_ts \})	ctx.reply(text)
Get message text	message.text	ctx.activity.text
Get sender	message.user (Slack ID)	ctx.activity.from.id (AAD ID)

Rating: GREEN — direct mapping in both directions.

Mitigation: Extract message handling into a platform-agnostic service layer that receives (text, userId, platform) and returns structured data. Each adapter converts to the platform's native format.

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Slash Commands

Aspect	Slack	Teams
Invocation	/command args	No native equivalent
Handler	app.command("/cmd", handler)	app.on("message") with text pattern matching
Acknowledgement	Must ack() within 3 seconds	Automatic — no ack()
Default response	Ephemeral (user-only)	Visible to everyone
Modal trigger	trigger_id from command → views.open()	dialog.open handler or Adaptive Card form
Registration	Slack app dashboard + commands scope	Manifest commands[] array (bot commands, not slash)

Rating: YELLOW — functional equivalent exists but UX is fundamentally different.

Impact

• Slash commands are a core Slack interaction pattern with no Teams counterpart
• Teams bot commands appear in a command menu but don't use / prefix
• Ephemeral responses don't exist in Teams

Mitigation Strategies

Strategy	How	Effort
Text commands (Recommended)	Detect command-like patterns in app.on("message"). Accept both weather and /weather.	2–4 hrs
Manifest bot commands	Add commands[] to manifest for discoverability in Teams command menu. Users type the command name.	1–2 hrs
Message extension	Use composeExtensions for a richer command experience with search results or task modules.	8–12 hrs

Reverse Direction (Teams → Slack)

Teams bot commands map directly to Slack slash commands via app.command(). Add ack() calls (required in Slack, absent in Teams) and configure the command in the Slack app dashboard.

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Events / Activities

Slack Event	Teams Activity	Notes
message	message	Direct mapping
app_mention	message (in channel)	Teams channels require @mention by default
member_joined_channel	conversationUpdate (membersAdded)	Different event shape
member_left_channel	conversationUpdate (membersRemoved)	Different event shape
reaction_added	messageReaction	Teams has only 6 fixed reactions
app_home_opened	install.add (closest)	No "opened" event in Teams
channel_created	No equivalent	Use Graph API subscription
team_join	conversationUpdate (membersAdded)	Same event, different context

Rating: GREEN for most events, RED for custom emoji reactions.

@Mention Behavior

Aspect	Slack	Teams
Channel messages	Bot receives all messages in joined channels	Bot only receives messages with @mention (default)
Override	Default behavior	Add ChannelMessage.Read.Group RSC permission to manifest
Mention stripping	Not needed	Set activity.mentions.stripText: true in App options

Mitigation: To receive all channel messages in Teams without @mention, add RSC permission to the manifest. This is a config-only change (1–2 hrs).

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Threading

Aspect	Slack	Teams
Reply in thread	say(\{ thread_ts: message.ts \})	ctx.reply(text)
Thread broadcast	say(\{ thread_ts, reply_broadcast: true \})	Two API calls: reply() + send()
Get thread replies	conversations.replies(\{ ts \})	Graph API GET /messages/\{id\}/replies
Thread discovery	Native API	Requires ChannelMessage.Read.All Graph permission

Rating: GREEN for basic threading, YELLOW for broadcast and discovery.

Mitigation for Thread Broadcast

Slack's reply_broadcast posts in both the thread and the channel in one call. Teams requires two separate calls: reply() for the thread and send() for the channel. Wrap in a helper:

async function replyWithBroadcast(ctx, text: string): Promise<void> {
  await ctx.reply(text);  // Thread reply
  await ctx.send(text);   // Channel message
}

Effort: 1–2 hrs.