Vouch request for per-task task agent overrides

[TechDufus]

Hey maintainers, I’d like to contribute a small improvement to the task tool: per-task agent overrides inside one batch.

The idea is to let one task call run different agent types while still sharing the same context. Right now a batch has one top-level agent, so mixed work needs separate calls even when it belongs together.

The behavior I’m adding keeps the top-level agent as the default, and lets an individual task override it:

{
  "agent": "explore",
  "context": "# Goal\nShared background for all tasks...",
  "tasks": [
    {
      "id": "ExploreRuntime",
      "assignment": "Inspect the local task runtime."
    },
    {
      "id": "ResearchDocs",
      "agent": "librarian",
      "assignment": "Check the external/library context."
    }
  ]
}

In that example, ExploreRuntime inherits explore, and ResearchDocs runs as librarian.

What this adds:

• tasks[].agent is optional
• effective agent is tasks[].agent ?? agent
• existing same-agent batches keep working
• mixed batches validate every effective agent before dispatch
• each item uses its resolved agent’s tools/model/output config
• the UI shows mixed batches clearly instead of making them look like one agent type

Here’s the local smoke test showing one mixed batch with explore and librarian:

Links:

• Original feature request: task: support per-task agent overrides in parallel batches #1403
• Original stale implementation PR: feat(coding-agent): support per-task task agents #1455
• Fresh implementation PR, closed automatically because I’m not vouched yet: feat(coding-agent): support per-task task agents #4740

I saw the vouch requirement in CONTRIBUTING.md, so I’m asking here before trying to reopen or resubmit the PR.

Could a maintainer please vouch me so this can go through normal PR review?

A !vouch @TechDufus here should unblock it.

[petzkod5]

Agree with this change. Would be useful for more complex orchestration level task delegation.