Adaptive Cards in Teams channel messages: fixed narrow width — request for width control

Hi Teams Platform team,

We post structured status reports as Adaptive Cards into a Teams channel. The card consistently renders at a fixed width of 448 px on a 1080p display at 100% scaling with a maximized Teams desktop client — well below the available channel message stream width. Wide multi-column tables get truncated or wrapped, which significantly hurts readability.

What we've tried

• No card-level `width` property exists in the Adaptive Cards schema.
• `msteams.width: "Full"` is documented to apply only to Stageview / task module / tab — silently ignored in channel messages (tested).
• Same payload via three delivery paths — Incoming Webhook, Logic App "Post adaptive card in chat or channel", and Microsoft Graph `POST /teams/{id}/channels/{id}/messages` — all render at the same narrow fixed width. The constraint is in the Teams channel-message renderer, not in any delivery layer.

Minimal repro payload (7-column results table; all field names and values replaced with generic placeholders):

{
  "type": "message",
  "attachments": [
    {
      "contentType": "application/vnd.microsoft.card.adaptive",
      "content": {
        "$schema": "https://adaptivecards.io/schemas/adaptive-card.json",
        "type": "AdaptiveCard",
        "version": "1.5",
        "msteams": { "width": "Full" },
        "body": [
          {
            "type": "TextBlock",
            "text": "Pipeline Report — run-001",
            "weight": "Bolder",
            "size": "Medium"
          },
          {
            "type": "Table",
            "gridStyle": "accent",
            "firstRowAsHeaders": true,
            "columns": [
              { "width": 2 }, { "width": 1 }, { "width": 2 },
              { "width": 1 }, { "width": 2 }, { "width": 1 }, { "width": 1 }
            ],
            "rows": [
              {
                "type": "TableRow",
                "cells": [
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "Col-1",   "weight": "Bolder", "size": "Small" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "Col-2",   "weight": "Bolder", "size": "Small" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "Col-3",   "weight": "Bolder", "size": "Small" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "Δ Col-3", "weight": "Bolder", "size": "Small" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "Col-4",   "weight": "Bolder", "size": "Small" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "Δ Col-4", "weight": "Bolder", "size": "Small" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "Status",  "weight": "Bolder", "size": "Small" }] }
                ]
              },
              {
                "type": "TableRow",
                "cells": [
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "item-a",     "size": "Small" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "mode-x",     "size": "Small" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "0.000/0.000","size": "Small" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "+0.00%",     "size": "Small", "color": "Good" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "0.000/0.000","size": "Small" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "-0.00%",     "size": "Small", "color": "Attention" }] },
                  { "type": "TableCell", "items": [{ "type": "TextBlock", "text": "✅ Pass",    "size": "Small" }] }
                ]
              }
            ]
          }
        ]
      }
    }
  ]
}

`msteams.width: "Full"` is present but has no visible effect in the channel message context.

Feature request

Either of:

1. Honor `msteams.width: "Full"` in channel-message context (not just Stageview/task module/tab), OR
2. Add a card-level property (e.g. `msteams.channelWidth: "Full" | "Default"`) explicitly scoped to channel messages.

Is this a known limitation with an existing tracking item, or should we also file it on the M365 Feedback Portal for upvotes?

Thanks!