Codex subagents render inside their parent session

August 10, 2026·paperctl CLI

Codex spawn_agent threads now appear inline in the parent session's trace — nested under the tool call that spawned them, at any depth — and the session's usage and cost totals include them.

When a Codex agent spawns subagents, the whole run now reads as one session. Each spawn_agent thread appears inline in the parent session’s trace, nested under the exact tool call that spawned it — parallel siblings, grandchildren, any depth. Follow-up messages sent into a running subagent stay under that same spawn point. Claude Code Task agents already worked this way; Codex sessions now match.

The rollups follow: a session’s token usage and cost totals include everything its subagents did, so the number you see on the sessions list is the real cost of the run, not just the root thread’s share.

Run paperctl upgrade to pick it up.

See How capture works for the full picture.

Codex subagents render inside their parent session

Start with paper