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Running 10 Claude Code Instances in Parallel — git worktree Isolation Design

#claudecode #git #buildinpublic #webdev

Running 10 Claude Code Instances in Parallel

The Problem: git stash Destroys Other Instances' Work

Running multiple Claude Code instances against the same repository causes silent data loss:

Instance A: editing lib/pages/home_page.dart (uncommitted)
Instance B: runs git pull --rebase
            → A's uncommitted changes get swept up in the rebase and lost

Instance C: runs git stash
            → Since all instances share the same workdir,
              A and B's changes end up in C's stash
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Root cause: all instances share the same working directory.

The Fix: Dedicated Worktree per Instance 

git worktree add .claude/worktrees/instance-ps1 -b claude/ps1-wip
git worktree add .claude/worktrees/instance-ps2 -b claude/ps2-wip
git worktree add .claude/worktrees/instance-vscode -b claude/vscode-wip
git worktree add .claude/worktrees/instance-win -b claude/win-wip
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Each instance operates exclusively in its own worktree. git stash and git pull --rebase in one instance have zero effect on others.

10-Instance Role Assignment 

PS#1     → .claude/worktrees/instance-ps1   (CI/WF health monitoring)
PS#2     → .claude/worktrees/instance-ps2   (blog post dispatch)
PS#3     → .claude/worktrees/instance-ps3   (AI university content)
PS#4     → .claude/worktrees/instance-ps4   (competitor monitoring)
PS#5     → .claude/worktrees/instance-ps5   (on-call bug fixes)
PS#6     → .claude/worktrees/instance-ps6   (batch jobs / horse racing)
VSCode   → .claude/worktrees/instance-vscode (UI / design)
Windows  → .claude/worktrees/instance-win   (AI university / migrations)
WEB      → no worktree needed (GitHub MCP only)
Mobile   → no worktree needed (GitHub MCP only)
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Setup Script 

#!/bin/bash
# .claude/scripts/setup-instance-worktree.sh
set -e

INSTANCE=$1
REPO_ROOT=$(git rev-parse --show-toplevel)
WORKTREE_DIR="$REPO_ROOT/.claude/worktrees/instance-$INSTANCE"
BRANCH="claude/${INSTANCE}-wip"

if [ -d "$WORKTREE_DIR" ]; then
  echo "worktree already exists: $WORKTREE_DIR"
  exit 0
fi

git worktree add "$WORKTREE_DIR" -b "$BRANCH" 2>/dev/null || \
  git worktree add "$WORKTREE_DIR" "$BRANCH"

echo "created: $WORKTREE_DIR (branch: $BRANCH)"
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Usage:

bash .claude/scripts/setup-instance-worktree.sh ps1
bash .claude/scripts/setup-instance-worktree.sh vscode
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Pushing to main

Each instance pushes its wip branch tip to main:

cd .claude/worktrees/instance-ps1

git add docs/GROWTH_STRATEGY_ROADMAP.md
git commit -m "ci: Rule17 health check"

git pull --rebase origin main
git push origin claude/ps1-wip:main
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When two instances push simultaneously, the second will get a "behind remote" rejection. Recovery:

git pull --rebase origin main   # fast-forward or resolve conflicts
git push origin claude/ps1-wip:main
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Registering Worktrees in .git/info/exclude

Worktrees are git internals — do not add them to .gitignore (that would break git worktree list). Instead use the local-only exclude file:

# .git/info/exclude
.claude/worktrees/
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List active worktrees at any time:

git worktree list
# /path/to/my_web_app                    abc1234 [main]
# /path/to/.claude/worktrees/instance-ps1  def5678 [claude/ps1-wip]
# /path/to/.claude/worktrees/instance-ps2  ghi9012 [claude/ps2-wip]
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Results

Problem Before After
stash interference Changes from other instances disappear Each instance has its own stash
pull --rebase Sweeps up other instances' uncommitted work Only affects the local wip branch
Parallel push Collision / overwrite risk Always rebase-clean before push
Debugging Unclear which instance made a change Traceable by wip branch name

Key Rules

  1. Never work in the main repo directory — it's push target only
  2. git stash is banned — WIP commit instead (git commit -m "WIP")
  3. commit before pull --rebase — staged-only changes can still be lost
  4. Edit → commit → push in a single bash invoke — prevents linter revert interference

Conclusion

git worktree is the standard solution for multiple processes sharing the same repository. For Claude Code's autonomous multi-instance model, it's not optional — it's the design. One worktree + wip branch per instance eliminates the entire class of "my changes disappeared" incidents.

Building in public: https://my-web-app-b67f4.web.app/

ClaudeCode #git #buildinpublic

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