When you have a directory created by a git worktree and you start the claude session on that directory, Claude code agent would not have memory of the main branch. Place this file inside ~/.claude/hooks/ and then update your ~/.claude/settings.json to use this

claude-link-worktree-memory.sh

#!/usr/bin/env bash
# SessionStart: point a git worktree's auto-memory dir at its main repo's.
#
# Auto-memory lives at ~/.claude/projects/<sanitized-cwd>/memory/, and a worktree
# has a different cwd than the repo it belongs to, so a session started in one
# begins blind to every memory written from the main checkout. This symlinks the
# worktree's memory dir onto the main repo's so both read and write one set.
#
# Bails out (exit 0, silent) unless it is safe: not a git repo, not a worktree,
# main repo has no memory dir yet, already linked, or the worktree dir already
# holds its own content.
set -uo pipefail

payload=$(cat 2>/dev/null || true)
cwd=$(printf '%s' "$payload" | jq -r '.cwd // empty' 2>/dev/null)
[ -n "$cwd" ] && [ -d "$cwd" ] || cwd=$(pwd)
cwd=$(cd "$cwd" 2>/dev/null && pwd -P) || exit 0

# --git-common-dir points at the ORIGINAL repo's .git for a worktree, and at the
# local .git otherwise, so its parent identifies the main checkout either way.
common=$(git -C "$cwd" rev-parse --git-common-dir 2>/dev/null) || exit 0
[ -n "$common" ] || exit 0
case "$common" in /*) ;; *) common="$cwd/$common" ;; esac
main=$(cd "$common/.." 2>/dev/null && pwd -P) || exit 0
[ "$main" = "$cwd" ] && exit 0

# Same sanitizing the harness applies to cwd: every non-alphanumeric becomes "-".
slug() { printf '%s' "$1" | tr -c 'A-Za-z0-9-' '-'; }

root="$HOME/.claude/projects"
target="$root/$(slug "$main")/memory"
mine="$root/$(slug "$cwd")/memory"

# Create the main repo's dir if it has none yet, rather than bailing: otherwise
# the first worktree of a fresh repo writes strays with nothing to link to.
mkdir -p "$target" 2>/dev/null || exit 0
[ "$mine" = "$target" ] && exit 0
[ -L "$mine" ] && exit 0

if [ -e "$mine" ] && [ -n "$(ls -A "$mine" 2>/dev/null)" ]; then
	printf '{"systemMessage":"auto-memory: %s already has its own files; not linking. Merge it into the main repo manually."}\n' "$mine"
	exit 0
fi

rmdir "$mine" 2>/dev/null
mkdir -p "$(dirname "$mine")" 2>/dev/null || exit 0
if ln -s "$target" "$mine" 2>/dev/null; then
	printf '{"systemMessage":"auto-memory linked to main repo: %s"}\n' "$(basename "$main")"
fi
exit 0