[Bug] Shell timeout does not settle a running tool part, leaving parent subagent blocked indefinitely #38276

Description

A shell tool call with an explicit timeout of 120000 ms remained in running state for about 19 minutes. The timeout did not produce a completed or error tool result, and the child session never emitted a terminal state. Because the child was launched through the Task tool, the parent agent remained blocked waiting for it.

The command output stopped at:

$ node scripts/sync-i18n.mjs
i18n sync done. Report: .../_sync-report.json
$ tsgo -b

The tool part remained status: running.

The child assistant message had no finish value and no error. The child session still had one in-progress todo item, but the main issue was that the verification shell call never settled.

Expected behavior:

• After the configured timeout, the command is terminated.
• If process termination or stream cleanup fails, the tool call is still finalized as an error/timeout.
• The child session receives a terminal error.
• The parent Task call receives a structured failure instead of waiting indefinitely.

Plugins

oh-my-openagent

OpenCode version

1.18.4

Steps to reproduce

1. Launch a subagent through the Task tool.
2. Ask it to run a long verification command with an explicit shell timeout, for example:
   bun run i18n:sync && bun run typecheck && bunx oxlint ...
3. Let the command enter a state where the process or one of its child processes does not terminate cleanly.
4. Observe that the shell tool part remains running after the timeout.
5. Observe that the child session and parent Task call remain blocked.

Operating System

macOS

Terminal

OpenChamber / OpenCode server