Reproduce an MCP bug with --mcp-config and --strict-mcp-config

Load a tiny set of servers from a JSON file for a single session and tell Claude Code to ignore your normal user/project MCP config. Great for bug reports, CI runs, and sandboxed reproductions.

bash

# 1. Save a minimal repro server config
cat > ./repro.json <<'JSON'
{
  "mcpServers": {
    "postgres-test": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-postgres", "postgres://localhost/repro"]
    }
  }
}
JSON

# 2. Launch with only that server, ignoring user/project MCP config
claude --strict-mcp-config --mcp-config ./repro.json

# 3. Or layer multiple files for CI runs
claude --mcp-config "./shared-servers.json ./ci-overrides.json"