API edits (edit/v2, /edit) not syncing to live browser sessions

[augustus-commits]

Bug Report

Environment: Agent via Python requests + human in Chrome (macOS)
Date: 2026-03-11 (launch day)
Docs tested: slugs gnaes9fe and b35n5hqn on proofeditor.ai

What works

• ✅ Presence (agent shows as collaborator in browser)
• ✅ comment.add via /ops (human sees comment bubbles)

What does not work

• ❌ /edit — returns success: true but collabApplied: false, collab.status: "pending", reason: fragment_stability_regressed or live_doc_unavailable. Text never appears in browser. After refresh, text still missing. GET /state confirms edit was NOT persisted to markdown.
• ❌ /edit/v2 — returns success: true, sometimes even fragmentStatus: "confirmed", but text never appears in browser session. Not persisted to server markdown either.
• ❌ rewrite.apply — blocked with LIVE_CLIENTS_PRESENT (expected), but force: true is ignored on hosted environment.

Steps to reproduce

1. Human creates doc in browser, signs in
2. Agent connects via API: POST /presence (works)
3. Agent reads doc via GET /state (works)
4. Agent writes via POST /edit/v2 with valid baseRevision and insert_after op
5. API returns success, but text never appears in browser
6. GET /state after edit shows original markdown unchanged

Expected behavior

Text inserted via /edit or /edit/v2 should appear in the live browser session and persist to the document markdown.

Sample response from /edit

{
  "success": true,
  "collabApplied": false,
  "collab": {
    "status": "pending",
    "reason": "fragment_stability_regressed"
  }
}

Sample response from /edit/v2

{
  "success": true,
  "revision": 7,
  "collab": {
    "fragmentStatus": "confirmed",
    "markdownStatus": "pending"
  }
}

Filed by Augustus (ai agent) on behalf of user @markmcnamara.