External agent processes (Codex ACP / Claude ACP) are never terminated when threads close, leaking dozens of processes and GBs of RAM

[limaronaldo]

Summary

Zed spawns external agent server processes (codex-acp, codex app-server, code-mode-host, claude-agent-acp) for Agent Panel threads, but never terminates them when a thread is closed or reset. Over a day of heavy agent usage, these accumulate as orphans.

Observed impact

After one day of use I found 55 live agent processes totaling 3.1 GB resident RSS (with virtual/compressed memory reported far higher by Activity Monitor). The oldest orphans were 2h+ old, belonging to threads long closed. Killing them manually (pkill -f codex-acp etc.) recovered ~2.6 GB immediately; Zed relaunches a clean process on the next thread with no ill effect.

Each codex app-server also loads the full skills/marketplace index into memory, so the per-process footprint multiplies quickly.

Steps to reproduce

1. Open the Agent Panel with an external ACP agent (e.g. Codex).
2. Start a thread, then close it (or start a new thread / reset).
3. Repeat several times.
4. ps aux | grep -E "codex-acp|codex app-server" — one process pair per thread remains, indefinitely.

Expected

Closing a thread (or at least quitting Zed) should terminate the associated agent server processes, or idle processes should be reaped after a timeout.

Environment

• Zed 1.11.3 (stable)
• macOS 26.5.2 (Darwin 25.5.0), Apple Silicon
• Agents: Codex ACP (codex-acp / codex app-server), Claude Code ACP

[zed-community-bot]

Additional recent context for triagers

Possibly related open issues:

• Zed does not kill Node.js processes upon exit, creating zombie processes #46474 — Issue Zed does not kill Node.js processes upon exit, creating zombie processes #46474 reports that Node.js processes spawned by Zed are not killed when Zed exits (Windows). The new issue reports that ACP agent server processes (codex-acp, claude-agent-acp) are not killed when threads close or Zed exits (macOS). Both stem from the same missing child-process lifecycle management — Zed spawns external processes but has no cleanup path. The trigger differs (thread close vs. Zed exit) and the process type differs (Node.js vs. ACP binaries), so there's some uncertainty about whether they share the exact same code path.
  • Possible shared root cause: Zed does not terminate child processes it spawns (agent/extension server processes) when they are no longer needed

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_{This is an automated analysis and might be incorrect.}