feat(pi): support pi reviewer model routing

skills/do-task/pi/SKILL.md

@@ -95,12 +95,24 @@ Use current-branch execution by default. Only switch to a worktree when the prom
 
 If the user already specified reviewer settings, use them. Otherwise ask:
 
-1. Reviewer CLI: `codex`, `claude`, `cursor`, `opencode`, or `skip`
+Reviewer CLI: `codex`, `claude`, `cursor`, `opencode`, `pi`, or `skip`
+
+1. Which CLI should review the plan and implementation?
 2. Reviewer model
 3. Max rounds, default `10`
 
 Store `REVIEWER_CLI`, `REVIEWER_MODEL`, and `MAX_ROUNDS`.
 
+When `REVIEWER_CLI=pi`, the reviewer model is configured independently from the pi model running this workflow. Use any configured pi model string, including provider-qualified model IDs. If the reviewer model or provider is unavailable, surface the review helper stderr/status and ask for a configured model; use `pi --list-models [search]` to inspect configured models.
+
+The pi reviewer command rendered into `/tmp/do-task-${REVIEW_KIND}-review-${REVIEW_ID}.sh` must be isolated and read-only:
+
+```bash
+pi --no-session --no-skills --no-prompt-templates --no-extensions --no-context-files --model "$REVIEWER_MODEL" --tools read,grep,find,ls -p "Read the file /tmp/do-task-${REVIEW_KIND}-${REVIEW_ID}.md and review."
+```
+
+The pi reviewer invocation must not load workflow skills and must not include `write`, `edit`, or `bash` tools.
+
 ### Phase 4: Initialize `task-plan.md`
 
 1. Compute `ai_plan/YYYY-MM-DD-<slug>/`

skills/do-task/pi/templates/task-plan.md

@@ -9,7 +9,7 @@
 | Created | YYYY-MM-DD |
 | Slug | YYYY-MM-DD-<slug> |
 | Runtime | pi |
-| Reviewer CLI | codex \| claude \| cursor \| opencode |
+| Reviewer CLI | codex \| claude \| cursor \| opencode \| pi |
 | Reviewer Model | <model> |
 | MAX_ROUNDS | 10 |
 | Branch Strategy | current-branch \| worktree |