diff --git a/Cargo.lock b/Cargo.lock
index 8b7d9a7..57db644 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -67,6 +67,12 @@ version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9e1b586273c5702936fe7b7d6896644d8be71e6314cfe09d3167c95f712589e8"
 
+[[package]]
+name = "base64"
+version = "0.21.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "414dcefbc63d77c526a76b3afcf6fbb9b5e2791c19c3aa2297733208750c6e53"
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -89,6 +95,12 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8d696c370c750c948ada61c69a0ee2cbbb9c50b1019ddb86d9317157a99c2cae"
 
+[[package]]
+name = "bumpalo"
+version = "3.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a3e2c3daef883ecc1b5d58c15adae93470a91d425f3532ba1695849656af3fc1"
+
 [[package]]
 name = "cc"
 version = "1.0.83"
@@ -119,6 +131,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "crc32fast"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b540bd8bc810d3885c6ea91e2018302f68baba2129ab3e88f32389ee9370880d"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "crunchy"
 version = "0.2.2"
@@ -155,13 +176,14 @@ checksum = "a26ae43d7bcc3b814de94796a5e736d4029efb0ee900c12e2d54c993ad1a1e07"
 
 [[package]]
 name = "els"
-version = "0.1.32-nightly.2"
+version = "0.1.33-nightly.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d64ff7aa566fa24ecc955cb17649f65eaa0401926a43785589864ebad8da4cd9"
+checksum = "8d90ce06b81836342feef59d9f1730340b39e32a9f488827c12919e3a9784cb2"
 dependencies = [
  "erg_common",
  "erg_compiler",
  "lsp-types",
+ "molc",
  "serde",
  "serde_json",
 ]
@@ -172,7 +194,7 @@ version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "af36f591236d9d822425cb6896595658fa558fcebf5ee8accac1d4b92c47166e"
 dependencies = [
- "base64",
+ "base64 0.13.1",
  "proc-macro2",
  "quote",
  "syn 1.0.109",
@@ -180,9 +202,9 @@ dependencies = [
 
 [[package]]
 name = "erg_common"
-version = "0.6.20-nightly.2"
+version = "0.6.21-nightly.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a5938643fcee96603ff9d1df6df3a5b088079d7e2122607fd9d374f60440cf02"
+checksum = "8c9e3dc0e21777787ea3fdc174f29fd6cdc8d7a6d671fcf7ed583c5f2c614956"
 dependencies = [
  "backtrace-on-stack-overflow",
  "parking_lot",
@@ -191,9 +213,9 @@ dependencies = [
 
 [[package]]
 name = "erg_compiler"
-version = "0.6.20-nightly.2"
+version = "0.6.21-nightly.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c88aaafbbe1eb293316e1e78af55acae6e840580f9b5a74aeed387a27c8c8988"
+checksum = "dfff095a4ce56412940dcf8d43e6897f85242365a9529c0d7e0cb10029668090"
 dependencies = [
  "erg_common",
  "erg_parser",
@@ -201,14 +223,24 @@ dependencies = [
 
 [[package]]
 name = "erg_parser"
-version = "0.6.20-nightly.2"
+version = "0.6.21-nightly.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a129213e4217d11ac5420afdb8e63bcca553d1cc4900e977f7619c4e1c801a6"
+checksum = "8a76f132bafed4fd84fb90a1c8f3ecde6a238f462ab2e8ca18e9d19ac27fd07c"
 dependencies = [
  "erg_common",
  "unicode-xid",
 ]
 
+[[package]]
+name = "flate2"
+version = "1.0.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c6c98ee8095e9d1dcbf2fcc6d95acccb90d1c81db1e44725c6a984b1dbdfb010"
+dependencies = [
+ "crc32fast",
+ "miniz_oxide",
+]
+
 [[package]]
 name = "form_urlencoded"
 version = "1.2.0"
@@ -292,6 +324,15 @@ version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "af150ab688ff2122fcef229be89cb50dd66af9e01a4ff320cc137eecc9bacc38"
 
+[[package]]
+name = "js-sys"
+version = "0.3.64"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c5f195fe497f702db0f318b07fdd68edb16955aed830df8363d837542f8f935a"
+dependencies = [
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "keccak"
 version = "0.1.4"
@@ -425,6 +466,17 @@ dependencies = [
  "adler",
 ]
 
+[[package]]
+name = "molc"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a19b669aab31ca7552fc43cb9ab08e325113aa090f7bf97a2112b3d6241ba898"
+dependencies = [
+ "lsp-types",
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "nix"
 version = "0.23.2"
@@ -597,6 +649,7 @@ dependencies = [
  "py2erg",
  "rustpython-ast",
  "rustpython-parser",
+ "ureq",
 ]
 
 [[package]]
@@ -673,6 +726,21 @@ dependencies = [
  "bitflags",
 ]
 
+[[package]]
+name = "ring"
+version = "0.16.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3053cf52e236a3ed746dfc745aa9cacf1b791d846bdaf412f60a8d7d6e17c8fc"
+dependencies = [
+ "cc",
+ "libc",
+ "once_cell",
+ "spin",
+ "untrusted",
+ "web-sys",
+ "winapi",
+]
+
 [[package]]
 name = "rustc-demangle"
 version = "0.1.23"
@@ -694,6 +762,38 @@ dependencies = [
  "semver",
 ]
 
+[[package]]
+name = "rustls"
+version = "0.21.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cd8d6c9f025a446bc4d18ad9632e69aec8f287aa84499ee335599fabd20c3fd8"
+dependencies = [
+ "log",
+ "ring",
+ "rustls-webpki 0.101.4",
+ "sct",
+]
+
+[[package]]
+name = "rustls-webpki"
+version = "0.100.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e98ff011474fa39949b7e5c0428f9b4937eda7da7848bbb947786b7be0b27dab"
+dependencies = [
+ "ring",
+ "untrusted",
+]
+
+[[package]]
+name = "rustls-webpki"
+version = "0.101.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d93931baf2d282fff8d3a532bbfd7653f734643161b87e3e01e59a04439bf0d"
+dependencies = [
+ "ring",
+ "untrusted",
+]
+
 [[package]]
 name = "rustpython-ast"
 version = "0.3.0"
@@ -763,6 +863,16 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
+[[package]]
+name = "sct"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d53dcdb7c9f8158937a7981b48accfd39a43af418591a5d008c7b22b5e1b7ca4"
+dependencies = [
+ "ring",
+ "untrusted",
+]
+
 [[package]]
 name = "semver"
 version = "1.0.18"
@@ -835,6 +945,12 @@ version = "1.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "62bb4feee49fdd9f707ef802e22365a35de4b7b299de4763d44bfea899442ff9"
 
+[[package]]
+name = "spin"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"
+
 [[package]]
 name = "static_assertions"
 version = "1.1.0"
@@ -988,6 +1104,28 @@ version = "0.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "446c96c6dd42604779487f0a981060717156648c1706aa1f464677f03c6cc059"
 
+[[package]]
+name = "untrusted"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a156c684c91ea7d62626509bce3cb4e1d9ed5c4d978f7b4352658f96a4c26b4a"
+
+[[package]]
+name = "ureq"
+version = "2.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b11c96ac7ee530603dcdf68ed1557050f374ce55a5a07193ebf8cbc9f8927e9"
+dependencies = [
+ "base64 0.21.3",
+ "flate2",
+ "log",
+ "once_cell",
+ "rustls",
+ "rustls-webpki 0.100.2",
+ "url",
+ "webpki-roots",
+]
+
 [[package]]
 name = "url"
 version = "2.4.1"
@@ -1012,6 +1150,101 @@ version = "0.9.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
 
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.87"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7706a72ab36d8cb1f80ffbf0e071533974a60d0a308d01a5d0375bf60499a342"
+dependencies = [
+ "cfg-if",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.87"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ef2b6d3c510e9625e5fe6f509ab07d66a760f0885d858736483c32ed7809abd"
+dependencies = [
+ "bumpalo",
+ "log",
+ "once_cell",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.31",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.87"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dee495e55982a3bd48105a7b947fd2a9b4a8ae3010041b9e0faab3f9cd028f1d"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.87"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "54681b18a46765f095758388f2d0cf16eb8d4169b639ab575a8f5693af210c7b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.31",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.87"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca6ad05a4870b2bf5fe995117d3728437bd27d7cd5f06f13c17443ef369775a1"
+
+[[package]]
+name = "web-sys"
+version = "0.3.64"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b85cbef8c220a6abc02aefd892dfc0fc23afb1c6a426316ec33253a3877249b"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "webpki-roots"
+version = "0.23.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b03058f88386e5ff5310d9111d53f48b17d732b401aeb83a8d5190f2ac459338"
+dependencies = [
+ "rustls-webpki 0.100.2",
+]
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
 [[package]]
 name = "windows-targets"
 version = "0.48.5"
diff --git a/Cargo.toml b/Cargo.toml
index 1be8f9b..049b82a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,9 +22,9 @@ edition = "2021"
 repository = "https://github.com/mtshiba/pylyzer"
 
 [workspace.dependencies]
-erg_common = { version = "0.6.20-nightly.2", features = ["py_compat", "els"] }
-erg_compiler = { version = "0.6.20-nightly.2", features = ["py_compat", "els"] }
-els = { version = "0.1.32-nightly.2", features = ["py_compat"] }
+erg_common = { version = "0.6.21-nightly.1", features = ["py_compat", "els"] }
+erg_compiler = { version = "0.6.21-nightly.1", features = ["py_compat", "els"] }
+els = { version = "0.1.33-nightly.1", features = ["py_compat"] }
 rustpython-parser = { version = "0.3.0", features = ["all-nodes-with-ranges", "location"] }
 rustpython-ast = { version = "0.3.0", features = ["all-nodes-with-ranges", "location"] }
 # rustpython-parser = { git = "https://github.com/RustPython/Parser", version = "0.3.0", features = ["all-nodes-with-ranges", "location"] }
@@ -50,6 +50,7 @@ els = { workspace = true }
 rustpython-parser = { workspace = true }
 rustpython-ast = { workspace = true }
 py2erg = { version = "0.0.43", path = "./crates/py2erg" }
+ureq = "2"
 
 [lib]
 path = "src/lib.rs"
diff --git a/README.md b/README.md
index 201b629..36099ef 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,12 @@
 
 ## Installation
 
+### pip
+
+```bash
+pip install pylyzer
+```
+
 ### cargo (rust package manager)
 
 ```bash
@@ -25,18 +31,6 @@ cargo install --path .
 
 Make sure that `cargo/rustc` is up-to-date, as pylyzer may be written with the latest language features.
 
-### pip
-
-```bash
-pip install pylyzer
-```
-
-__If installed this way, you also need to [install Erg](https://github.com/mtshiba/ergup).__
-
-```bash
-curl -L https://github.com/mtshiba/ergup/raw/main/ergup.py | python3
-```
-
 ### [GitHub Releases](https://github.com/mtshiba/pylyzer/releases/latest)
 
 ## What is the advantage over pylint, pyright, pytype, etc.?
diff --git a/src/download.rs b/src/download.rs
new file mode 100644
index 0000000..7cb65f5
--- /dev/null
+++ b/src/download.rs
@@ -0,0 +1,16 @@
+use std::error::Error;
+
+use erg_common::env::erg_path;
+use erg_common::python_util::exec_py_code;
+
+#[allow(unused)]
+pub(crate) fn download_dependencies() -> Result<(), Box<dyn Error>> {
+    if erg_path().exists() {
+        return Ok(());
+    }
+    println!("Erg standard library not found. Installing...");
+    let install_script_url = "https://github.com/mtshiba/ergup/raw/main/ergup.py";
+    let code = ureq::get(install_script_url).call()?.into_string()?;
+    exec_py_code(&code, &[])?;
+    Ok(())
+}
diff --git a/src/lib.rs b/src/lib.rs
index f83b4e6..22e397d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,6 @@
 mod analyze;
 mod config;
+mod download;
 mod handle_err;
 
 pub use analyze::PythonAnalyzer;
diff --git a/src/main.rs b/src/main.rs
index cf4bffa..a67862c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,16 +1,19 @@
 mod analyze;
 mod config;
+mod download;
 mod handle_err;
 
 use analyze::{PythonAnalyzer, SimplePythonParser};
+use download::download_dependencies;
 use els::Server;
 use erg_common::config::ErgMode;
 use erg_common::spawn::exec_new_thread;
 
 fn run() {
+    download_dependencies().unwrap();
     let cfg = config::parse_args();
     if cfg.mode == ErgMode::LanguageServer {
-        let mut lang_server = Server::<PythonAnalyzer, SimplePythonParser>::new(cfg);
+        let mut lang_server = Server::<PythonAnalyzer, SimplePythonParser>::new(cfg, None);
         lang_server.run().unwrap_or_else(|_| {
             std::process::exit(1);
         });