feat: allow custom subagents to delegate tasks via task()

[Stranmor]

Summary

Custom subagents defined in oh-my-opencode.json cannot use task() to delegate work to other agents. This PR fixes three independent issues that collectively prevent the pipeline from working.

Problem

When a user defines custom agents (e.g., critic, breaker, type-sentinel) in oh-my-opencode.json, those agents:

1. Cannot call task() — buildSubagentTools() hardcodes task: false for background tasks and only allows task for plan-family agents in sync flows
2. Are never registered with opencode — applyAgentConfig() passes custom agents as overrides to createBuiltinAgents(), which only processes known builtin names
3. Are blocked by global permission deny — applyToolConfig() sets config.permission.task = "deny" globally, then only whitelists hardcoded agents

Changes

Commit 1 (agent-tool-restrictions.ts): Check AGENT_RESTRICTIONS instead of hardcoding task: false. 4 code paths fixed.

Commit 2 (agent-config-handler.ts, tool-config-handler.ts): Register custom agents from config. Grant task: "allow" to non-restricted agents.

[cubic-dev-ai]

1 issue found across 11 files

Confidence score: 2/5

• Potential deadlock in src/features/background-agent/spawner.ts when nested agents share a low-limit concurrency key and both try to acquire it, which can block parent/child execution
• Severity is high (8/10) with plausible user-facing hangs, so merge risk is elevated despite being a single issue
• Pay close attention to src/features/background-agent/spawner.ts - nested concurrency acquisition can stall agents

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="src/features/background-agent/spawner.ts">

<violation number="1" location="src/features/background-agent/spawner.ts:143">
P1: Potential deadlock when nested agents share concurrency key with low limits. Parent acquires slot and invokes task tool (now enabled), child attempts to acquire same key but blocks because parent holds it while waiting for child completion.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P1: Potential deadlock when nested agents share concurrency key with low limits. Parent acquires slot and invokes task tool (now enabled), child attempts to acquire same key but blocks because parent holds it while waiting for child completion.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At src/features/background-agent/spawner.ts, line 143:

<comment>Potential deadlock when nested agents share concurrency key with low limits. Parent acquires slot and invokes task tool (now enabled), child attempts to acquire same key but blocks because parent holds it while waiting for child completion.</comment>

<file context>
@@ -140,12 +140,7 @@ export async function startTask(
-        call_omo_agent: true,
-        question: false,
-      },
+      tools: buildSubagentTools(input.agent),
       parts: [{ type: "text", text: input.prompt }],
     },
</file context>

[sisyphus-dev-ai]

@Stranmor Thanks for the PR! There are a couple of items to address before we can merge:

1. Merge conflicts: This branch currently has conflicts that need to be resolved.

2. Cubic review feedback: The AI reviewer identified a potential deadlock issue in src/features/background-agent/spawner.ts around line 143. The concern is about nested agents sharing a concurrency key with low limits - when a parent acquires a slot and invokes the task tool, a child attempting to acquire the same key could block because the parent holds it while waiting for child completion.

Could you take a look at these issues? Once the conflicts are resolved and the deadlock concern is addressed (or explained if it is not a real issue), we can proceed with the review.

Thanks!