Before submitting
Area
apps/desktop
Steps to reproduce
-
Start T3 Code Desktop.
-
Open a Codex-backed thread with the T3 preview MCP tools available.
-
Save this minimal page as open-visible-repro.html:
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>T3 Preview Open Visibility Repro</title>
</head>
<body>
<h1>T3 Preview Open Visibility Repro</h1>
<p id="ready">Loaded</p>
</body>
</html>
-
Serve the directory containing that file:
python -m http.server 8000
-
Call preview_status.
-
Call preview_open with show: true, reuseExistingTab: true, and the page URL:
{
"show": true,
"reuseExistingTab": true,
"url": "http://localhost:8000/open-visible-repro.html"
}
-
Optionally call preview_open again with show: true and the returned tabId:
{
"show": true,
"reuseExistingTab": true,
"tabId": "<returned tabId>"
}
-
Verify that the loaded page is still available to automation:
({
title: document.title,
ready: document.querySelector("#ready").textContent
})
Expected behavior
When preview_open(show: true) returns, the preview panel should be displayed to the user and the returned status should report visible: true.
If the browser cannot be shown, the tool should report a clear failure or return a state that explains why the tab is not visible.
Actual behavior
preview_open(show: true) returned a usable tabId, loaded the URL, and allowed later automation, but reported visible: false:
{
"available": true,
"visible": false,
"tabId": "tab_h",
"url": "http://localhost:8000/open-visible-repro.html",
"title": "T3 Preview Open Visibility Repro",
"loading": false,
"viewportSetting": { "_tag": "fill" },
"viewport": { "width": 1280, "height": 800 }
}Calling preview_open(show: true) again with the same tabId still returned visible: false.
The page was loaded and available to automation despite visible: false:
{
"title": "T3 Preview Open Visibility Repro",
"ready": "Loaded"
}Later operations in the same session caused the same tab's visibility state to move between false and true, so agents cannot infer from show: true that the user can actually see the preview.
Impact
Major degradation or frequent failure
Version or commit
T3 Code desktop 0.0.28-1 via t3code-bin AUR package.
Environment
Arch Linux x86_64, kernel 7.0.13-arch1-1, T3 Code desktop AppImage package via t3code-bin, Codex provider.
Logs or stack traces
No stack trace. The relevant evidence is the returned preview_open status above.
Screenshots, recordings, or supporting files
Minimal repro page attached above. A screenshot can show whether the human-visible preview panel opened, but the core bug is visible in the tool return state: show: true returns a loaded tab with visible: false.
Workaround
Treat visible as user display state only, not as an agent automation capability signal. Verify whether the tab is usable with preview_evaluate, preview_wait_for, or URL/title fields from preview_status. If the user-visible browser matters, manually reopen or create a fresh tab.
Before submitting
Area
apps/desktop
Steps to reproduce
Start T3 Code Desktop.
Open a Codex-backed thread with the T3 preview MCP tools available.
Save this minimal page as
open-visible-repro.html:Serve the directory containing that file:
Call
preview_status.Call
preview_openwithshow: true,reuseExistingTab: true, and the page URL:{ "show": true, "reuseExistingTab": true, "url": "http://localhost:8000/open-visible-repro.html" }Optionally call
preview_openagain withshow: trueand the returnedtabId:{ "show": true, "reuseExistingTab": true, "tabId": "<returned tabId>" }Verify that the loaded page is still available to automation:
Expected behavior
When
preview_open(show: true)returns, the preview panel should be displayed to the user and the returned status should reportvisible: true.If the browser cannot be shown, the tool should report a clear failure or return a state that explains why the tab is not visible.
Actual behavior
preview_open(show: true)returned a usabletabId, loaded the URL, and allowed later automation, but reportedvisible: false:{ "available": true, "visible": false, "tabId": "tab_h", "url": "http://localhost:8000/open-visible-repro.html", "title": "T3 Preview Open Visibility Repro", "loading": false, "viewportSetting": { "_tag": "fill" }, "viewport": { "width": 1280, "height": 800 } }Calling
preview_open(show: true)again with the sametabIdstill returnedvisible: false.The page was loaded and available to automation despite
visible: false:{ "title": "T3 Preview Open Visibility Repro", "ready": "Loaded" }Later operations in the same session caused the same tab's visibility state to move between
falseandtrue, so agents cannot infer fromshow: truethat the user can actually see the preview.Impact
Major degradation or frequent failure
Version or commit
T3 Code desktop
0.0.28-1viat3code-binAUR package.Environment
Arch Linux x86_64, kernel
7.0.13-arch1-1, T3 Code desktop AppImage package viat3code-bin, Codex provider.Logs or stack traces
No stack trace. The relevant evidence is the returned
preview_openstatus above.Screenshots, recordings, or supporting files
Minimal repro page attached above. A screenshot can show whether the human-visible preview panel opened, but the core bug is visible in the tool return state:
show: truereturns a loaded tab withvisible: false.Workaround
Treat
visibleas user display state only, not as an agent automation capability signal. Verify whether the tab is usable withpreview_evaluate,preview_wait_for, or URL/title fields frompreview_status. If the user-visible browser matters, manually reopen or create a fresh tab.