agent: subagent (Task tool) returns prematurely in feature workflow #63764

Summary

Subagent (Task tool) returns prematurely in feature workflow — main agent receives completion signal before subagent actually finishes, causing "build done" to be reported while implementation is still running.

Environment

• opencode version: 2.0.32
• OS: Windows_NT 10.0.19044 (win32 x64)
• Terminal: Unavailable: terminal environment variables are not set
• Shell: C:\WINDOWS\system32\cmd.exe
• Install/channel: latest
• Active plugins: None found in config

Reproduction

1. Start a feature workflow using sdd-developer skill (or feature-tdd skill)
2. Main agent spawns a subagent via Task tool for implementation (e.g., TDD implementation of a task)
3. Main agent outputs: "agent bitince bildirim alıp devam edeceğim" (will wait for notification when agent finishes)
4. Immediately after, main agent outputs: "build done" — indicating it believes the subagent completed
5. But the subagent was still running (implementation not actually finished)

Expected Behavior

Main agent should wait for the subagent to actually complete (return its result) before proceeding to the next step (review, verification, or reporting "build done").

Actual Behavior

Main agent receives a premature completion signal from the Task tool invocation. The subagent continues running in the background but the main agent has already moved on, reporting "build done" and potentially starting the next phase (review/verification) on incomplete work.

Additional Context

• Frequency: Every time (100% reproducible in feature workflow with sdd-developer)
• Skills involved: sdd-developer (and likely feature-tdd which has similar subagent orchestration)
• Workflow: Feature implementation → spawns Implementation Subagent → should wait for result → spawns Review Subagent → etc.
• Impact: Broken feature implementations, incomplete code, false "done" reports, verification running on half-finished work
• Suspected cause: Race condition in Task tool completion handling — the tool returns before the subagent process actually terminates
• Workarounds tried: None — this is a core runtime issue

The user's exact description (Turkish): "agent bitince bildirim alıp devam edeceğim yazıyor sonrasında buişld done yazıyor" — meaning the agent says it will wait for notification when the subagent finishes, then immediately writes "build done".