codex - 💡(How to fix) Fix Codex remote compaction deadlocks when input_image payloads remain in compacted replacement history

{
    "schemaVersion": 1,
    "generatedAt": "1779667950s since unix epoch",
    "overallStatus": "fail",
    "codexVersion": "0.133.0",
    "checks": {
      "app_server.status": {
        "id": "app_server.status",
        "category": "app-server",
        "status": "ok",
        "summary": "background server is not running",
        "details": {
          "control socket": "/home/mrenda/.codex/app-server-control/app-server-control.sock",
          "daemon state dir": "/home/mrenda/.codex/app-server-daemon",
          "mode": "ephemeral",
          "pid file": "/home/mrenda/.codex/app-server-daemon/app-server.pid (missing)",
          "settings": "/home/mrenda/.codex/app-server-daemon/settings.json (missing)",
          "status": "not running",
          "update-loop pid file": "/home/mrenda/.codex/app-server-daemon/app-server-updater.pid (missing)"
        },
        "remediation": null,
        "durationMs": 0
      },
      "auth.credentials": {
        "id": "auth.credentials",
        "category": "auth",
        "status": "ok",
        "summary": "auth is configured",
        "details": {
          "auth env vars present": "OPENAI_API_KEY",
          "auth file": "/home/mrenda/.codex/auth.json",
          "auth storage mode": "File",
          "stored API key": "false",
          "stored ChatGPT tokens": "true",
          "stored agent identity": "false",
          "stored auth mode": "chatgpt"
        },
        "remediation": null,
        "durationMs": 0
      },
      "config.load": {
        "id": "config.load",
        "category": "config",
        "status": "ok",
        "summary": "config loaded",
        "details": {
          "CODEX_HOME": "/home/mrenda/.codex",
          "config.toml": "/home/mrenda/.codex/config.toml",
          "config.toml parse": "ok",
          "cwd": "/home/mrenda/projects/kuzys",
          "model": "gpt-5.5",
          "model provider": "openai",
          "sqlite home": "/home/mrenda/.codex"
        },
        "remediation": null,
        "durationMs": 0
      },
      "installation": {
        "id": "installation",
        "category": "install",
        "status": "ok",
        "summary": "installation looks consistent",
        "details": {
          "PATH codex #1": "/usr/local/bin/codex",
          "managed by npm": "true",
          "managed package root": "/usr/local/lib/node_modules/@openai/codex",
          "npm update target": "/usr/local/lib/node_modules/@openai/codex"
        },
        "remediation": null,
        "durationMs": 392
      },
      "runtime.provenance": {
        "id": "runtime.provenance",
        "category": "runtime",
        "status": "ok",
        "summary": "running npm on linux-x86_64",
        "details": {
          "platform": "linux-x86_64",
          "version": "0.133.0"
        },
        "remediation": null,
        "durationMs": 0
      },
      "state.paths": {
        "id": "state.paths",
        "category": "state",
        "status": "ok",
        "summary": "state paths and databases are inspectable",
        "details": {
          "CODEX_HOME": "/home/mrenda/.codex (dir)",
          "active rollout files": "191 files, 5226839601 total bytes, 27365652 average bytes",
          "state DB": "/home/mrenda/.codex/state_5.sqlite (file)",
          "state DB integrity": "ok"
        },
        "remediation": null,
        "durationMs": 385
      },
      "terminal.env": {
        "id": "terminal.env",
        "category": "terminal",
        "status": "ok",
        "summary": "terminal metadata was detected",
        "details": {
          "COLORTERM": "truecolor",
          "terminal": "GNOME Terminal",
          "terminal size": "80x24"
        },
        "remediation": null,
        "durationMs": 2
      }
    }
  }

Codex ran out of room in the model's context window. Start a new thread or clear earlier history before retrying.

Error running remote compact task:
{
  "error": {
    "message": "Your input exceeds the context window of this model. Please adjust your input and try again.",
    "type": "invalid_request_error",
    "param": "input",
    "code": "context_length_exceeded"
  }
}

{
  "type": "compacted",
  "payload": {
    "replacement_history": [
      {
        "type": "message",
        "role": "user",
        "content": [
          { "type": "input_text", "text": "..." },
          { "type": "input_image", "image_url": "data:image/png;base64,..." },
          { "type": "input_text", "text": "..." }
        ]
      }
    ]
  }
}

Observed affected local threads contained:

- 2 image payloads / ~530 KB image JSON
- 4 image payloads / ~669 KB image JSON
- 9 image payloads / ~2.0 MB image JSON
- 21 image payloads / ~9.2 MB image JSON

After manually replacing only those input_image parts in the latest compacted replacement history with small text markers, the sessions were able to resume without creating new threads.

Uploaded thread 019e0a2b-ffe3-7332-9276-6f6832f8680d contains the investigation and mitigation discussion. The actual affected private rollout files cannot be uploaded because they contain private
session data.



### What is the expected behavior?

Remote compaction should not preserve raw historical `input_image` payloads indefinitely inside active compacted replacement history.

Expected behavior would be one of:

1. omit `input_image` parts from compacted replacement history;
2. replace historical image payloads with lightweight markers;
3. summarize image existence without keeping base64/data URL payloads;
4. strip image payloads before sending history to the remote compaction model;
5. provide a built-in recovery path if compaction fails due to oversized historical payloads.

A session should not become permanently unable to resume because the compaction request itself exceeds context.



### Additional information

Local mitigation used successfully:

1. Back up `~/.codex`.
2. Create a single-file backup of the affected rollout.
3. Modify only the latest `type=compacted` record.
4. Inside `payload.replacement_history`, replace only `input_image` parts with small textual markers.
5. Leave thread id, DB metadata, message order, summaries, text content, and session pointers unchanged.
6. Validate JSONL after modification.

After this surgical repair, affected sessions resumed successfully without starting new threads.

This strongly suggests that preserved `input_image` payloads inside compacted replacement history are the direct trigger.

Privacy note: I cannot provide full rollout files because they contain private session data. I can provide redacted JSON shapes, exact log lines, structural counts, before/after hashes, and
details of the successful mitigation.