brain/scripts/lib/merge-mcp.sh

#!/usr/bin/env bash
# Merge brain MCP template into consumer's claude.json or project .mcp.json
# Mode: user (merge into ~/.claude.json:mcpServers) or project (merge into <repo>/.mcp.json:mcpServers)
# Preserves consumer-specific servers; brain-managed servers override on key collision.
#
# Usage: merge-mcp.sh --mode=user|project <target> <brain-mcp.json>
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
source "$SCRIPT_DIR/common.sh"

mode=""
case "${1:-}" in
    --mode=user) mode="user"; shift ;;
    --mode=project) mode="project"; shift ;;
    *) log_error "First arg must be --mode=user or --mode=project"; exit 1 ;;
esac

target="$1"
brain_mcp="$2"

require_cmd jq || exit 1
[ -f "$brain_mcp" ] || { log_error "Brain MCP file not found: $brain_mcp"; exit 1; }

# If target missing, copy brain template
if [ ! -f "$target" ]; then
    log_info "Target $target missing, creating from brain template"
    cp "$brain_mcp" "$target"
    exit 0
fi

# Backup
backup="${target}.bak.$(date +%s)"
cp "$target" "$backup"

# CORRECTION B (Bug 1 fix): use --argjson with shell-read content instead of
# --slurpfile. jq on Windows MSYS2 cannot open paths with non-ASCII characters
# (Cyrillic etc.) via its C-level fopen, but cat is a shell builtin/coreutil
# that handles UTF-8 paths fine. --argjson takes a pre-parsed JSON string, so
# this works regardless of path encoding.
#
# Merge semantics: target.mcpServers (or {} if missing) UNION brain.mcpServers,
# with brain entries overriding on key collision (laravel-boost stays — brain
# template doesn't define it; magic gets replaced if brain defines it).
brain_content=$(cat "$brain_mcp")
tmp="${target}.tmp"
jq --argjson brain "$brain_content" \
   '.mcpServers = ((.mcpServers // {}) + $brain.mcpServers)' \
   "$target" > "$tmp"

# Validate
jq empty "$tmp" || { log_error "Merge produced invalid JSON"; rm "$tmp"; exit 1; }

mv "$tmp" "$target"
log_info "MCP ($mode mode) merged (backup: $backup)"