Skip to content

Remote compaction v2 retains raw media and can trigger repeated auto-compaction #38835

Open
Open
Remote compaction v2 retains raw media and can trigger repeated auto-compaction#38835
Labels
appIssues related to the Codex desktop appbugSomething isn't workingcontextIssues related to context management (including compaction)

Description

@LeonSGP43
LeonSGP43
opened on Aug 16, 2026

Summary

In a long-running Codex Desktop session with image inputs, repeated remote compaction retained raw media payloads in replacement history. The session then kept auto-compacting and the rollout grew continuously.

Observed behavior

  • A successful compaction did not remove earlier inline image payloads from the retained history.
  • Subsequent compaction requests carried those payloads forward again.
  • The retained payload volume created a high context floor and repeated automatic compaction.

Root-cause hypothesis

The v2 retained-history path in codex-rs/core/src/compact_remote_v2.rs assigns zero text-token cost to InputImage and InputAudio, while preserving the raw items during truncation. Therefore a byte-heavy media item can survive the text-only budget indefinitely across compactions.

Expected behavior

After successful compaction, retained history must not contain raw image or audio payloads from previous turns, and all retained context should remain bounded by the retention budget.

Proposed fix

Before retained-history budget truncation, replace InputImage and InputAudio with bounded text markers. This preserves conversation structure without resending or persisting raw media. Add regression coverage that asserts compacted retained history contains no data:image or audio payload and that markers are charged by the existing budget.

Related discussion

This is a current reproduction and source-level analysis related to #33493.

Activity

  1. github-actions
    added
    bugSomething isn't working
    appIssues related to the Codex desktop app
    contextIssues related to context management (including compaction)
    on Aug 16, 2026

  2. github-actions commented on Aug 16, 2026

    @github-actions
    github-actionsbot
    on Aug 16, 2026 – with GitHub Actions
    Contributor

    Potential duplicates detected. Please review them and close your issue if it is a duplicate.

    Powered by Codex Action

  3. LeonSGP43 commented on Aug 16, 2026

    @LeonSGP43
    LeonSGP43
    on Aug 16, 2026
    Author

    Sanitized reproduction data

    The following is a structural-only scan of one affected local rollout. No transcript text, prompts, file paths, screenshots, tool output, account identifiers, or raw media is included.

    Environment and capture window

    Field Value
    Client version recorded at session start 0.144.6
    History mode legacy
    Session start 2026-07-25 08:28:28 UTC
    Last recorded event at scan time 2026-08-16 04:13:14 UTC
    Writer state rollout file was still open by the running Codex process

    Measured rollout shape

    Metric Value
    Rollout size 10,057,075,750 bytes, 9.4 GiB as reported by du
    JSONL records 64,983
    context_compacted records 494
    Literal input_image occurrences 30,202

    Compaction concentration

    The event timestamps show a pronounced late-session acceleration. Counts below are UTC and are structural event counts only.

    Date context_compacted records
    2026-08-13 19
    2026-08-14 32
    2026-08-15 269
    2026-08-16 through 04:13 UTC 35

    The 269 compactions on 2026-08-15 correspond to an average interval of about 5.4 minutes across that UTC day. The problem persisted after compactions rather than resolving the history pressure.

    Source-level correlation

    In codex-rs/core/src/compact_remote_v2.rs:

    1. message_text_token_count assigns zero text-token cost to InputImage and InputAudio.
    2. truncate_message_text_to_token_budget preserves those media items unchanged.
    3. The retained items are installed into the compaction replacement history and can be sent again on later compaction cycles.

    This makes a media-heavy retained history effectively unbounded with respect to the text-only retention budget, matching the measured growth and recurring compaction pattern.

    Acceptance criteria for a fix

    1. A successful remote v2 compaction leaves no raw data:image or audio payload in retained replacement history.
    2. Retained media is represented by bounded text only and participates in the existing retention budget.
    3. Repeated compactions do not reintroduce prior raw media into the next request or persisted rollout history.
    4. The regression test uses synthetic media only and asserts complete response-item structure, without recording user data.

  4. Rina48 commented on Aug 16, 2026

    @Rina48
    Rina48
    on Aug 16, 2026 – with ChatGPT Codex Connector

    Additional Windows reproduction on a current Desktop build

    Corroborating this on Windows 11 x64 with Codex Desktop
    26.810.7004.0, embedded CLI 0.148.0-alpha.9, gpt-5.6-sol,
    and remote_compaction_v2 enabled during the incident.

    A structural-only scan of one image-heavy thread showed:

    • rollout size of approximately 400 MiB;
    • dozens of persisted compaction records;
    • hundreds of repeated input_image / data:image occurrences across
      replacement histories; these were not unique images;
    • 13 compaction attempts during the final approximately 30-minute window;
    • every compact HTTP request returned 200 OK, but token usage remained above
      the automatic-compaction threshold, causing another compaction roughly every
      2–3 minutes.

    This distinction may be useful: the failure was not only a transport error.
    Compaction succeeded at the HTTP layer but did not re-establish enough context
    headroom to converge, leaving the Desktop session unusable.

    No transcript text, prompts, paths, task or thread identifiers, screenshots,
    raw logs, media, account information, or repository content is included.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    appIssues related to the Codex desktop appbugSomething isn't workingcontextIssues related to context management (including compaction)

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions