Teams App Developer

ui-legacy-attachments-cards-ts

purpose

Bridges pre-Block Kit Slack legacy attachments and Teams Adaptive Cards for cross-platform bots targeting Slack, Teams, or both.

rules

1. Slack legacy attachments (message.attachments[]) predate Block Kit and use a flat JSON structure with text, fallback, color, callback_id, and actions[]. These map to a single Adaptive Card with TextBlock body elements and Action.Submit actions.

2. Slack app.attachmentAction(callback_id) handles button clicks on legacy attachments. In Teams, this maps to app.on('adaptiveCards.actionSubmit') or app.adaptiveCards.actionSubmit(verb, handler) where verb is embedded in Action.Submit.data.

3. Slack legacy attachment color (hex string like "#3AA3E3" or named like "good", "warning", "danger") maps to Adaptive Card Container with style property: "good" → "good", "warning" → "warning", "danger" → "attention". For custom hex colors, wrap the card content in a Container with "style": "emphasis" (no arbitrary hex colors in Adaptive Cards).

4. Slack legacy attachment fallback (plain-text fallback for notifications) maps to the fallback property on the Adaptive Card's content object (e.g., { ..., "fallback": "Fallback text for notifications" }). Always provide this for accessibility.

5. Slack legacy attachment actions[] with type: "button" map to Adaptive Card Action.Submit buttons. The button name and value become keys in Action.Submit.data. The callback_id becomes the verb routing key.

6. Slack legacy confirm objects (confirmation dialogs on buttons) have no direct Adaptive Card equivalent. Redesign as: (a) an Action.ShowCard that reveals a confirmation sub-card with Confirm/Cancel buttons, or (b) a two-step flow where the first click sends a confirmation card and the second click executes the action.

7. Slack attachment_type: "default" has no Adaptive Card equivalent — it was a Slack internal marker. Remove it during migration.

8. Slack legacy attachment actions[] with type: "select" (dropdown menus) map to Adaptive Card Input.ChoiceSet with style: "compact". Remember that Adaptive Card selects require an explicit Action.Submit button — they do not fire on selection like Slack.

9. Slack respond({ replace_original: true }) (replacing the original message after an attachment action) maps to Teams updateActivity() with the original activity ID and a new Adaptive Card attachment.

10. Messages mixing legacy attachments AND Block Kit blocks should be bridged to a single Adaptive Card. The attachment text becomes header/body TextBlock elements and the Block Kit portion follows the standard block-kit-to-adaptive-cards mapping.

11. Reverse direction (Teams → Slack): While not recommended (Block Kit is preferred), Adaptive Cards can be mapped to legacy attachment format if targeting very old Slack integrations. Map TextBlock to attachments[].text, Container style to color, and Action.Submit to actions[].type: "button". Prefer converting to Block Kit instead of legacy attachments for new Slack integrations.

patterns

Legacy attachment with buttons → Adaptive Card

Slack (before):

// --- Slack legacy attachment JSON ---
val message = """
{
  "text": "Would you like to play a game?",
  "attachments": [
    {
      "text": "Choose a game to play",
      "fallback": "You are unable to choose a game",
      "callback_id": "wopr_game",
      "color": "#3AA3E3",
      "attachment_type": "default",
      "actions": [
        { "name": "game", "text": "Chess", "type": "button", "value": "chess" },
        { "name": "game", "text": "Falken's Maze", "type": "button", "value": "maze" },
        {
          "name": "game",
          "text": "Thermonuclear War",
          "style": "danger",
          "type": "button",
          "value": "war",
          "confirm": {
            "title": "Are you sure?",
            "text": "Wouldn't you prefer a good game of chess?",
            "ok_text": "Yes",
            "dismiss_text": "No"
          }
        }
      ]
    }
  ]
}
"""

app.attachmentAction("wopr_game") { req, ctx ->
    ctx.respond(secondMessage)
    ctx.ack()
}

Teams (after):

import { App } from '@microsoft/teams.apps';
import { ConsoleLogger } from '@microsoft/teams.common';

const app = new App({
  logger: new ConsoleLogger('game-bot'),
});

// The game selection card (replaces legacy attachment)
const gameCard = {
  type: 'AdaptiveCard' as const,
  version: '1.5',
  fallback: 'You are unable to choose a game',
  body: [
    {
      type: 'TextBlock',
      text: 'Would you like to play a game?',
      size: 'Medium',
      weight: 'Bolder',
    },
    {
      type: 'TextBlock',
      text: 'Choose a game to play',
      wrap: true,
    },
  ],
  actions: [
    {
      type: 'Action.Submit',
      title: 'Chess',
      data: { verb: 'wopr_game', game: 'chess' },
    },
    {
      type: 'Action.Submit',
      title: "Falken's Maze",
      data: { verb: 'wopr_game', game: 'maze' },
    },
    {
      // Dangerous action — use Action.ShowCard for confirmation
      type: 'Action.ShowCard',
      title: 'Thermonuclear War',
      card: {
        type: 'AdaptiveCard',
        body: [
          {
            type: 'TextBlock',
            text: "Are you sure? Wouldn't you prefer a good game of chess?",
            wrap: true,
            color: 'Attention',
          },
        ],
        actions: [
          {
            type: 'Action.Submit',
            title: 'Yes',
            style: 'destructive',
            data: { verb: 'wopr_game', game: 'war' },
          },
          // "No" simply collapses the ShowCard — no action needed
        ],
      },
    },
  ],
};

// Send the game card when the user says "play"
app.on('message', async ({ activity, send }) => {
  if (activity.text?.match(/play/i)) {
    await send({
      type: 'message',
      attachments: [{
        contentType: 'application/vnd.microsoft.card.adaptive',
        content: gameCard,
      }],
    });
  }
});

// Handle game selection (replaces app.attachmentAction("wopr_game"))
// TODO: Replace with app.adaptiveCards.actionSubmit if using teams-ai SDK
app.on('adaptiveCards.actionSubmit' as any, async ({ activity, send }) => {
  const data = activity.value;
  if (data?.verb === 'wopr_game') {
    const game = data.game;
    await send(`You chose: ${game}. Let's play!`);
    // TODO: Send the follow-up card (replaces secondMessage / replace_original)
  }
});

app.start(3978);

Mapping reference table

pitfalls

• No arbitrary colors: Slack attachments support any hex color via the color field. Adaptive Cards only support semantic styles ("good", "warning", "attention", "emphasis", "accent", "default"). Map to the closest semantic meaning rather than exact color matching.

• Confirmation dialogs require redesign: Slack's confirm object is a built-in dialog. Adaptive Cards have no equivalent. Action.ShowCard is the closest — it reveals an inline sub-card. For a modal confirmation, use a task module flow instead.

• Select fires differently: Slack legacy selects fire immediately on selection. Adaptive Card Input.ChoiceSet requires a separate Action.Submit click. This changes the UX — inform users of the change.

• Mixed attachments + blocks: Some Slack messages combine legacy attachments with Block Kit blocks. Merge both into a single Adaptive Card. The attachment text becomes TextBlocks at the top, followed by the converted Block Kit elements.

• replace_original requires activity ID: Slack's respond({ replace_original: true }) works with just the response_url. In Teams, you need the original activity ID to call updateActivity(). Store the activity ID when you send the card (returned from send()).

• callback_id routing: Slack routes attachment actions by callback_id. Teams routes by the verb (or custom key) in Action.Submit.data. Ensure every button includes a routing key in its data object.

references

• https://api.slack.com/reference/messaging/attachments — Slack legacy attachments (deprecated but supported)

• https://api.slack.com/legacy/interactive-messages — Legacy interactive messages (attachment actions)

• https://adaptivecards.io/explorer/Action.ShowCard.html — Action.ShowCard (inline reveal)

• https://adaptivecards.io/explorer/Container.html — Container with style property

• https://learn.microsoft.com/en-us/microsoftteams/platform/task-modules-and-cards/cards/cards-reference — Teams card reference

• https://github.com/microsoft/teams.ts — Teams SDK v2

instructions

Use this expert when adding cross-platform support in either direction for Slack legacy attachments or Teams Adaptive Cards. It covers converting attachment JSON to Adaptive Card JSON and vice versa, mapping attachmentAction handlers to actionSubmit handlers, redesigning confirmation dialogs, handling message replacement, and dealing with mixed attachment + Block Kit messages. For Teams → Slack, Adaptive Cards can be mapped to legacy attachment format if targeting very old Slack integrations, though Block Kit is preferred. Pair with ui-block-kit-adaptive-cards-ts.md if the message also contains Block Kit blocks, and ../teams/ui.adaptive-cards-ts.md for Adaptive Card construction patterns.

research

Deep Research prompt:

"Write a micro expert on bridging Slack legacy message attachments (pre-Block Kit) and Teams Adaptive Cards in either direction for cross-platform bots. Cover: attachment text/color/fallback/callback_id/actions mapping, button and select action conversion, confirm dialog redesign with Action.ShowCard, attachmentAction handler bridging to adaptiveCards.actionSubmit, replace_original to updateActivity, mixed attachments + Block Kit messages, color mapping limitations, and reverse-direction notes for Teams → Slack legacy attachment mapping. Include a worked example converting between formats."