fix: redirect native task tool to delegate_task for problematic agents

[kunal70006]

Summary

• Adds task-to-delegate-redirect hook to intercept native task tool calls
• Redirects to delegate_task for agents with known issues (metis, oracle, momus, atlas)
• Preserves original task arguments while adding required delegate_task parameters

Problem

The native OpenCode task tool returns empty responses (only session_id metadata) for certain agents due to token refresh issues. delegate_task works correctly for the same agents.

Diagnostic evidence from issue #1281:

Agent	mcp_task	mcp_delegate_task
metis	Empty response	Full response
oracle	Empty response	Full response
explore	Works	Works
librarian	Works	Works

Fixes #1281

Changes

• src/hooks/task-to-delegate-redirect/index.ts - New hook implementation
• src/hooks/index.ts - Export new hook
• src/index.ts - Import, instantiate, and wire up hook

Implementation Details

• Hook is conditionally enabled via isHookEnabled("task-to-delegate-redirect")
• Only affects problematic agents (metis, momus, oracle, atlas)
• Non-breaking: explore/librarian and other agents pass through unchanged
• Follows existing hook patterns (like delegate-task-retry)

Testing

• Verified hook pattern matches existing hooks
• Hook runs BEFORE the existing if (input.tool === "task") block to ensure redirect happens first

---

Summary by cubic

Redirects native task tool calls to delegate_task for problematic agents to prevent empty responses. Adds a pre-execution hook for metis, momus, oracle, and atlas. Fixes #1281.

• Bug Fixes
  • Added task-to-delegate-redirect hook to map task → delegate_task on tool.execute.before for affected agents.
  • Preserves task args and sets delegate_task fields (description, prompt, session_id, run_in_background=false, load_skills=[]).
  • Gated by isHookEnabled("task-to-delegate-redirect") and runs before the task handler; other agents are unchanged.

^{Written for commit 825e6c2. Summary will update on new commits.}

[github-actions]

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[cubic-dev-ai]

No issues found across 3 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

[kunal70006]

I have read the CLA Document and I hereby sign the CLA

[code-yeongyu]

Closing this PR - the root cause has been identified and fixed upstream.

Root Cause: OpenCode bugs (not oh-my-opencode)

• Issue #11289 (empty response bug in prompt_async) - Fixed on 2026-01-30
• Native task tool only extracts text type parts, ignoring reasoning type

Resolution: Update to latest OpenCode version

Note: oh-my-opencode's delegate_task already extracts both text + reasoning parts, so the current approach of directing agents to use delegate_task is correct.