feat(opencode): allow general nested task via depth

[samuelrizzo]

Issue for this PR

No issue filed.

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Nested subagents need two things today: subagent_depth >= 2 and a task: allow override on the agent. The built-in general agent denies todowrite but says nothing about task, so deriveSubagentSessionPermission adds an implicit task deny and hides the tool from the child. That means setting subagent_depth: 2 alone is not enough for general -> general, which is surprising next to the docs.

This adds task: allow to the default permission of general (one line in packages/opencode/src/agent/agent.ts). The depth check in task.ts is untouched, so the default (depth=1) still blocks nesting; you only get one nested level when you explicitly opt in with subagent_depth: 2. I left explore alone since it is read-only by design, and I did not change the default depth.

How did you verify your code works?

I tried bun test test/tool/task.test.ts in packages/opencode but the suite does not boot in this env (missing @opentui/solid/preload), unrelated to this diff. I verified the one-line diff by reading deriveSubagentSessionPermission + visibleTools paths and confirmed the existing depth tests (prevents subagents from launching subagents by default, allows nested subagents up to the configured depth) cover the gate I left in place.

Screenshots / recordings

Not a UI change.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

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What needs to be fixed:

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found one potentially related PR:

PR #32301: feat: nested sub-agent spawning (up to 5 levels) + fixes for #23091 / #13715

• feat: nested sub-agent spawning (up to 5 levels) + fixes for #23091 / #13715 #32301
• This PR addresses nested sub-agent spawning functionality, which is related to the depth/nesting mechanism in PR feat(opencode): allow general nested task via depth #47106. However, it appears to be a past implementation that this PR may be improving or refactoring.

PR #37902: fix(acp): child/subagent session permission requests no longer hang forever

• fix(acp): child/subagent session permission requests no longer hang forever #37902
• This addresses subagent session permissions, which is tangentially related to the permission-related changes in this PR.

The current PR #47106 appears to be a targeted fix/improvement rather than a full duplicate. It specifically aligns the behavior of the task tool on the general agent with documentation by removing an implicit permission restriction, which is different from past nested subagent implementations.

[github-actions]

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