Current Windows Desktop still fails remote compaction for image-heavy long-running tasks (reconnect 5/5)

Summary

A long-running, image-heavy Codex Desktop task repeatedly enters Reconnecting 1/5 through Reconnecting 5/5 during automatic context compaction and then reports:

Error running remote compact task: stream disconnected before completion: error sending request for url (https://chatgpt.com/backend-api/codex/responses)

This is still reproducible on the current Windows Desktop build. The affected task can remain slow or unresponsive for minutes, while ordinary tasks in the same app and Codex CLI on the same machine respond normally.

Environment

• Product: Codex Desktop
• App version: 26.721.11231.0
• Platform: Windows 11 x64
• Observed: July 2026
• Task pattern: long-running task with repeated image/browser inputs and many automatic compactions

Reproduction pattern

1. Keep one Codex Desktop task active across many turns.
2. Add screenshots or browser/image-tool results over time.
3. Allow automatic compaction to occur repeatedly.
4. Send an otherwise routine text request when the task is near another compaction.
5. Observe Context automatically compacting, repeated reconnect attempts, and sometimes the remote compact error above.

Sanitized diagnostic evidence

A read-only inspection of the affected task found:

• The append-only rollout had grown past 1 GB after many compactions.
• The latest active replacement history was approximately 51 MB uncompressed (approximately 38 MB compressed).
• The active history retained dozens of historical inline images; image data accounted for nearly all payload bytes.
• The same remote-compaction stream failure recurred on multiple days.
• A compaction retry can eventually succeed, but historical image payloads remain in replacement history, so the oversized request shape and failure risk return.
• HTTP reachability and the Responses WebSocket handshake were healthy.
• Control tasks in the same Desktop process had much smaller request payloads and responded normally.
• Lowering model/reasoning effort improved an ordinary response but did not remove the oversized compaction payload or prevent recurrence.

No private rollout, screenshots, local paths, task IDs, project details, or user content are attached.

Actual behavior

• Automatic compaction sends a very large image-heavy replacement history.
• The response stream disconnects before completion.
• Desktop retries up to five times and may remain stuck or slow for minutes.
• Even after a successful retry, retained historical image bytes make the problem recur.

Expected behavior

• Compaction should summarize, externalize, or deduplicate historical image bytes rather than carry full inline payloads indefinitely.
• Request and retained-image size should remain bounded across repeated compactions.
• If remote compaction fails, Desktop should recover with a supported fallback instead of an extended reconnect loop.
• The UI should identify payload/compaction pressure distinctly from a general network failure.

Related reports

• #34863 — repeated inline PNG data URLs make compacted records and app-server memory grow
• #24550 — large inline images in compacted replacement_history trigger Responses WebSocket fallback
• #30958 — exact stream disconnected before completion endpoint error on Windows Desktop
• #31375 — context compression disconnects repeatedly in the Codex App
• #32545 — Windows Desktop remote-compaction disconnect regression

This report is intended as a current Windows Desktop corroboration tying the exact remote-compaction error and reconnect loop to measured image-heavy replacement-history payload pressure.