codex - 💡(How to fix) Fix Codex app-server repeatedly killed by SIGKILL after memory grows to ~27GB when handling large tool/log output

(code=null, signal=SIGKILL).

Most recent error:
{"timestamp":"2026-05-22T07:26:01.761510Z","level":"WARN","fields":{"message":"could not find callback for Integer(1)"},"target":"codex_app_server::outgoing_message"}
{"timestamp":"2026-05-22T07:26:01.761563Z","level":"WARN","fields":{"message":"could not find callback for Integer(0)"},"target":"codex_app_server::outgoing_message"}

### What steps can reproduce the bug?

I do not have a minimal deterministic repro yet, but the bug happened repeatedly during a Codex crash investigation on 2026-05-22.

Observed pattern:

Run Codex Desktop on macOS.
Have the VS Code Codex extension installed/enabled at the same time, so both Codex Desktop and the VS Code extension may run app-server processes.
In a Codex session, investigate previous crashes or logs using commands that can produce large output, for example:
rg ~/.codex/sessions
/usr/bin/log show
ps -axo ...
Codex app-server memory grows very large.
Eventually the Codex UI shows: (code=null, signal=SIGKILL).
The UI asks to reload Codex. This happened multiple times in one day. In one case the whole computer became unstable and rebooted.

### What is the expected behavior?

Codex app-server should not be able to grow to tens of GB of memory due to tool/log output. Large command output should be capped, streamed, discarded, or backpressured before it is accumulated in app-server memory.

Suggested product-side fixes:

Add a hard output cap before app-server stores or serializes tool output.
Apply streaming discard/backpressure for terminal/log output.
Do not rely only on UI truncation; truncation should happen before backend memory accumulation.
Add memory budget isolation for tool output so one large command cannot kill the app-server.
Consider detecting high-risk commands that may emit unbounded output and require explicit confirmation or automatic output limiting.
If VS Code extension and Codex Desktop both run app-server processes, make this safer or clearer to users.

### Additional information

_No response_