Add "lessons/sprints/sprint-8---parallel-hook-optimization-success"

lessons%2Fsprints%2Fsprint-8---parallel-hook-optimization-success.-.md

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+# Sprint 8 - Parallel Hook Optimization Success
+
+## Metadata
+- **Implementation:** [Change V5.5.0 (Sprint 8)](https://gitea.hotserv.cloud/personal-projects/leo-claude-mktplace/wiki/Change-V5.5.0%3A-Hook-Efficiency-Quick-Wins-%28Sprint-8-Implementation%29)
+- **Issues:** #321, #322, #323, #324
+- **Sprint:** Sprint 8
+
+## Context
+
+Implementing RFC-Hook-Efficiency-Improvements Phase 1: Quick Wins. Four independent hook optimization tasks needed to be executed.
+
+## What Went Well
+
+1. **File Conflict Detection Validated:** Pre-dispatch analysis confirmed no file overlap between tasks:
+   - #321 → `plugins/viz-platform/hooks/hooks.json`
+   - #322 → `plugins/git-flow/hooks/branch-check.sh`
+   - #323 → `plugins/git-flow/hooks/commit-msg-check.sh`
+   - #324 → `plugins/project-hygiene/hooks/cleanup.sh`
+
+2. **Parallel Execution Worked:** All 4 executor agents ran simultaneously without conflicts.
+
+3. **Simple Changes, High Impact:** Each change was XS/S effort but addresses real performance issues:
+   - Removed zero-value echo hook
+   - Added early exit for 90%+ of Bash commands
+   - Added cooldown to reduce filesystem scans
+
+## Lessons for Future Sprints
+
+1. **Hook optimization is low-hanging fruit:** Most hooks can be optimized with simple early-exit checks.
+
+2. **Early grep before expensive operations:** Pattern `if ! grep -q 'pattern'; then exit 0; fi` is extremely effective for PreToolUse hooks.
+
+3. **Session-scoped cooldowns via $PPID:** Using `/tmp/hook-name-${PPID}-last-run` effectively limits hook frequency per session without affecting other sessions.
+
+## Tags
+hooks, performance, bash, parallel-execution, optimization, quick-wins
+
+---
+**Tags:** hooks, performance, bash, parallel-execution, optimization