E27 stack: conditional impl tier + final-review tier pin + narration recipe + terse reviewer contract

skills/subagent-driven-development/SKILL.md

@@ -11,6 +11,9 @@ Execute plan by dispatching a fresh implementer subagent per task, a task review
 
 **Core principle:** Fresh subagent per task + task review (spec + quality) + broad final review = high quality, fast iteration
 
+**Narration:** between tool calls, narrate at most one short line — the
+ledger and the tool results carry the record.
+
 **Continuous execution:** Do not pause to check in with your human partner between tasks. Execute all tasks from the plan without stopping. The only reasons to stop are: BLOCKED status you cannot resolve, ambiguity that genuinely prevents progress, or all tasks complete. "Should I continue?" prompts and progress summaries waste their time — they asked you to execute the plan, so execute it.
 
 ## When to Use
@@ -88,6 +91,8 @@ Use the least powerful model that can handle each role to conserve cost and incr
 **Integration and judgment tasks** (multi-file coordination, pattern matching, debugging): use a standard model.
 
 **Architecture and design tasks**: use the most capable available model.
+The final whole-branch review is one of these — dispatch it on the most
+capable available model, not the session default.
 
 **Review tasks**: choose the model with the same judgment, scaled to the
 diff's size, complexity, and risk. A small mechanical diff does not need the