The 40-line cap not moving rate limits makes sense - plan text is cheap. The cost is in Phase 1 exploration.
Plan mode spins up to 3 explore subagents before the planner even starts, and the heuristic is "use multiple when scope is uncertain." It won't choose fewer - it's being asked to plan, so scope is always uncertain. Nothing penalizes claude for over-exploring and nothing rewards restraint.
Plan mode also ignores session state. A cold start gets the same fanout as a warm session where the relevant files are already in context. In a warm session the explore pass is pure waste - it re-reads loaded files and feeds the planner lossy summaries that conflict with what it already knows.
More tokens, worse plan.
If exploration was conditional on what's already in context..skip it for warm sessions, keep it for cold starts - that does more for both rate limits and plan quality than a hard 40-line cap.
Note: plan mode didn’t always have this 3 subagent fan out behavior attached to it, it was introduced around opus 4.6 launch.
Plan mode spins up to 3 explore subagents before the planner even starts, and the heuristic is "use multiple when scope is uncertain." It won't choose fewer - it's being asked to plan, so scope is always uncertain. Nothing penalizes claude for over-exploring and nothing rewards restraint.
Plan mode also ignores session state. A cold start gets the same fanout as a warm session where the relevant files are already in context. In a warm session the explore pass is pure waste - it re-reads loaded files and feeds the planner lossy summaries that conflict with what it already knows.
More tokens, worse plan.
If exploration was conditional on what's already in context..skip it for warm sessions, keep it for cold starts - that does more for both rate limits and plan quality than a hard 40-line cap.
Note: plan mode didn’t always have this 3 subagent fan out behavior attached to it, it was introduced around opus 4.6 launch.