AI Threads census returns zero threads when VS Code uses single-tab mode (showTabs: single)

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John Lauer · 4d ago

Hydrogen 1.0.648, 2026-10-19 ~02:40Z.

With the VS Code setting "workbench.editor.showTabs": "single", the AI Threads census finds nothing:

GET /ai-threads → groups[0].threads: [], summary: {running_sessions: 2, live_composer_contexts: 2, total_ai_threads: 0, unmatched_live: 2}
POST /ai-threads/focus {"sid": "<a live Claude session>"} → ok: false
POST /ai-threads/resume {"ai":"claude","id":"<sid>"} → ok: false, error: "history UI not reachable in any webview" (see the separate issue)

Running workbench.action.showMultipleEditorTabs makes the same call list all 23 threads at once, and focus works. Switching back to single tabs breaks it again.

Single-tab mode is useful for screen recordings (it hides other projects' tab names), so the census should not depend on the tab strip DOM, or at least should report that it cannot see the tabs instead of returning an empty tree.

2 Replies

John Lauer · 4d ago

Also affects delivery: POST /ai-threads/run-prompt {"tid":"g0t15",...} fails with "no AI thread tab matching 'g0t15'" while single-tab mode is on, even when the tid came from a census taken a moment earlier with tabs shown. Only /claude/inject into the foreground Claude tab works.

John Lauer · 3d ago

Fixed in 7fc60257 (next build after 1.0.658, not built yet).

The census read the editor tab strip, and with "workbench.editor.showTabs": "single" the strip renders only the active editor, so every other thread vanished. adom-vscode already knows every tab through the VS Code API (window.tabGroups, its GET /tabs). Now, when it lists more tabs for a group than the strip shows, that group's rows come from its list instead. tid positions match the API's, so focus (which reveals by position through the extension), run-prompt {tid|sid} and the "no AI thread tab matching" path all see the same threads as with multiple tabs. The census says where the rows came from: summary.tabs_from is "extension" or "tab-strip".

Gate scenario ai-threads-single-tab: in single-tab mode the census lists as many threads as with multiple tabs, and focus by the sid of a thread not in front makes it active. I will close this once that passes on the build. The resume "history UI not reachable" part is tracked in #125.