Goal

Give every thread a visible role with an icon, cut the roles down to five, and make the difference between kinds of subagents obvious.

Owner request (2026-10-12):

• Role icons for each thread.
• Standard roles: Orchestrator, Implementor, Reviewer, Investigator, Checker.
• An easy way to tell native subagents (which "run on their own, open parent") apart from real threads you can type into.
• Split subagents into two groups:
  • native subagents working in the same place as their orchestrator;
  • child threads working in their own worktree, which are essentially issue agents.

What exists today

• Two unrelated role lists, neither stored on threads.
  • Model-role ids in settings (DEFAULT_MODEL_ROLES, settings.ts ~1248–1327): orchestrator, fast-builder, checker, thorough-builder, bounded-worker, evidence-gatherer, quick-claude, strong-reviewer. These only feed agent prompts.
  • delegate_task's role: implementation, research, review, design, test, general (orchestratorMcp.ts ~145). It only prefixes the prompt and picks the default workspace.
  • Neither is saved on the child thread (OrchestrationV2AppThread has no role field), and sidebar rows show no role.
• Issue-work roots and workers are inferred from repositoryOrchestration and linkedIssue.
• Native versus app-owned.
  • isProviderNativeSubagentThread (relationshipToParent === "subagent" && creationSource === "provider") is used by ProviderSubagentBar.tsx ("Runs on its own" / "Open parent").
  • The sidebar nesting, the timeline divider and the header breadcrumb treat both kinds the same.
• Own worktree versus shared. This is known only by comparing worktreePath with the parent's (childWorktreeLabel).

Proposed

1. Five roles. Make the five roles the one list used for both model roles and delegate_task's role, with a mapping from the old ids so saved settings keep working.
   • Model choices per role stay user-configurable, and stay ranked by usage (Subagents ask their orchestrator; fix t3_request_user_input; usage-weighted model choice #12).
   • Open decision: how fast/thorough builder variants fit. For example Implementor could have a fast and a thorough model choice.
2. Store the role on the thread when it is created: delegated children from delegate_task, issue roots as Orchestrator, issue workers as Implementor. Top-level user threads have no role, or Orchestrator if they delegate.
3. Show a role icon in the sidebar row, as a column (Sidebar rows in fixed columns: location, role, provider, model, effort, name, time, work, usage #19), and in the chat header.
4. Mark the two subagent kinds clearly:
   • Native subagents: read-only, same workspace, "runs on its own". A distinct icon or style, no input affordance.
   • Child threads: own thread you can type into, usually its own worktree, often issue agents. They look like normal threads, nested under their orchestrator.

Mobile is out of scope. Related: #12 (roles ranked by usage), #8 (issue agents).