diff --git a/README.ja.md b/README.ja.md
index 9621a207..4c288e89 100644
--- a/README.ja.md
+++ b/README.ja.md
@@ -184,6 +184,31 @@ smoke_obj_array = "NYASH_LLVM_OBJ_OUT={root}/nyash_llvm_temp.o ./target/release/
 
 ---
 
+## 🧰 一発ビルド（MVP）: `nyash --build`
+
+`nyash.toml` を読み、プラグイン → コア → AOT → リンクまでを一発実行する最小ビルド機能です。
+
+基本（Cranelift AOT）
+```bash
+./target/release/nyash --build nyash.toml \
+  --app apps/egui-hello-plugin/main.nyash \
+  --out app_egui
+```
+
+主なオプション（最小）
+- `--build <path>`: nyash.toml の場所
+- `--app <file>`: エントリ `.nyash`
+- `--out <name>`: 出力EXE名（既定: `app`/`app.exe`）
+- `--build-aot cranelift|llvm`（既定: cranelift）
+- `--profile release|debug`（既定: release）
+- `--target <triple>`（必要時のみ）
+
+注意
+- LLVM AOT には LLVM 18 が必要（`LLVM_SYS_180_PREFIX` を設定）。
+- GUIを含む場合、AOTのオブジェクト出力時にウィンドウが一度開きます（閉じて続行）。
+- WSL で表示されない場合は `docs/guides/cranelift_aot_egui_hello.md` のWSL Tips（Wayland→X11切替）を参照。
+
+
 ## 📊 **パフォーマンスベンチマーク**
 
 実世界ベンチマーク結果 (ny_bench.nyash)：
diff --git a/README.md b/README.md
index ce56141f..6256bb85 100644
--- a/README.md
+++ b/README.md
@@ -160,6 +160,31 @@ cargo build --release --features wasm-backend
 
 ---
 
+## 🧰 One‑Command Build (MVP): `nyash --build`
+
+Reads `nyash.toml`, builds plugins → core → emits AOT object → links an executable in one shot.
+
+Basic (Cranelift AOT)
+```bash
+./target/release/nyash --build nyash.toml \
+  --app apps/egui-hello-plugin/main.nyash \
+  --out app_egui
+```
+
+Key options (minimal)
+- `--build <path>`: path to nyash.toml
+- `--app <file>`: entry `.nyash`
+- `--out <name>`: output executable (default: `app`/`app.exe`)
+- `--build-aot cranelift|llvm` (default: cranelift)
+- `--profile release|debug` (default: release)
+- `--target <triple>` (only when needed)
+
+Notes
+- LLVM AOT requires LLVM 18 (`LLVM_SYS_180_PREFIX`).
+- Apps that open a GUI may show a window during AOT emission; close it to continue.
+- On WSL if the window doesn’t show, see `docs/guides/cranelift_aot_egui_hello.md` (Wayland→X11).
+
+
 ## 📊 **Performance Benchmarks**
 
 Real-world benchmark results (ny_bench.nyash):
diff --git a/src/cli.rs b/src/cli.rs
index f100f0fe..8d3fe09e 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -57,6 +57,13 @@ pub struct CliConfig {
     // Phase-15: JSON IR v0 bridge
     pub ny_parser_pipe: bool,
     pub json_file: Option<String>,
+    // Build system (MVP)
+    pub build_path: Option<String>,
+    pub build_app: Option<String>,
+    pub build_out: Option<String>,
+    pub build_aot: Option<String>,
+    pub build_profile: Option<String>,
+    pub build_target: Option<String>,
 }
 
 impl CliConfig {
@@ -317,6 +324,43 @@ impl CliConfig {
                     .help("Opt-in: read [ny_plugins] from nyash.toml and load scripts in order")
                     .action(clap::ArgAction::SetTrue)
             )
+            // Build system (MVP)
+            .arg(
+                Arg::new("build")
+                    .long("build")
+                    .value_name("PATH")
+                    .help("Build AOT executable using nyash.toml at PATH (MVP)")
+            )
+            .arg(
+                Arg::new("build-app")
+                    .long("app")
+                    .value_name("FILE")
+                    .help("Entry Nyash script for --build (e.g., apps/hello/main.nyash)")
+            )
+            .arg(
+                Arg::new("build-out")
+                    .long("out")
+                    .value_name("FILE")
+                    .help("Output executable name for --build (default: app/app.exe)")
+            )
+            .arg(
+                Arg::new("build-aot")
+                    .long("build-aot")
+                    .value_name("{cranelift|llvm}")
+                    .help("AOT backend for --build (default: cranelift)")
+            )
+            .arg(
+                Arg::new("build-profile")
+                    .long("profile")
+                    .value_name("{release|debug}")
+                    .help("Cargo profile for --build (default: release)")
+            )
+            .arg(
+                Arg::new("build-target")
+                    .long("target")
+                    .value_name("TRIPLE")
+                    .help("Target triple for --build (e.g., x86_64-pc-windows-msvc)")
+            )
     }
 
     /// Convert ArgMatches to CliConfig
@@ -361,6 +405,12 @@ impl CliConfig {
             parser_ny: matches.get_one::<String>("parser").map(|s| s == "ny").unwrap_or(false),
             ny_parser_pipe: matches.get_flag("ny-parser-pipe"),
             json_file: matches.get_one::<String>("json-file").cloned(),
+            build_path: matches.get_one::<String>("build").cloned(),
+            build_app: matches.get_one::<String>("build-app").cloned(),
+            build_out: matches.get_one::<String>("build-out").cloned(),
+            build_aot: matches.get_one::<String>("build-aot").cloned(),
+            build_profile: matches.get_one::<String>("build-profile").cloned(),
+            build_target: matches.get_one::<String>("build-target").cloned(),
         }
     }
 }
diff --git a/src/runner/mod.rs b/src/runner/mod.rs
index 325e5718..37f3ed76 100644
--- a/src/runner/mod.rs
+++ b/src/runner/mod.rs
@@ -75,6 +75,14 @@ impl NyashRunner {
 
     /// Run Nyash based on the configuration
     pub fn run(&self) {
+        // Build system (MVP): nyash --build <nyash.toml>
+        if let Some(cfg_path) = self.config.build_path.clone() {
+            if let Err(e) = self.run_build_mvp(&cfg_path) {
+                eprintln!("❌ build error: {}", e);
+                std::process::exit(1);
+            }
+            return;
+        }
         // Phase-15: JSON IR v0 bridge (stdin/file)
         if self.config.ny_parser_pipe || self.config.json_file.is_some() {
             let json = if let Some(path) = &self.config.json_file {
@@ -808,6 +816,145 @@ impl NyashRunner {
             }
         }
     }
+
+    /// Minimal AOT build pipeline driven by nyash.toml (MVP, single-platform, best-effort)
+    fn run_build_mvp(&self, cfg_path: &str) -> Result<(), String> {
+        use std::path::{Path, PathBuf};
+        let cwd = std::env::current_dir().unwrap_or(PathBuf::from("."));
+        let cfg_abspath = if Path::new(cfg_path).is_absolute() { PathBuf::from(cfg_path) } else { cwd.join(cfg_path) };
+        // 1) Load nyash.toml
+        let text = std::fs::read_to_string(&cfg_abspath).map_err(|e| format!("read {}: {}", cfg_abspath.display(), e))?;
+        let doc = toml::from_str::<toml::Value>(&text).map_err(|e| format!("parse {}: {}", cfg_abspath.display(), e))?;
+        // 2) Apply [env]
+        if let Some(env_tbl) = doc.get("env").and_then(|v| v.as_table()) {
+            for (k, v) in env_tbl.iter() { if let Some(s) = v.as_str() { std::env::set_var(k, s); } }
+        }
+        // Derive options
+        let profile = self.config.build_profile.clone().unwrap_or_else(|| "release".into());
+        let aot = self.config.build_aot.clone().unwrap_or_else(|| "cranelift".into());
+        let out = self.config.build_out.clone();
+        let target = self.config.build_target.clone();
+        // 3) Build plugins: read [plugins] values as paths and build each
+        if let Some(pl_tbl) = doc.get("plugins").and_then(|v| v.as_table()) {
+            for (name, v) in pl_tbl.iter() {
+                if let Some(path) = v.as_str() {
+                    let p = if Path::new(path).is_absolute() { PathBuf::from(path) } else { cwd.join(path) };
+                    let mut cmd = std::process::Command::new("cargo");
+                    cmd.arg("build");
+                    if profile == "release" { cmd.arg("--release"); }
+                    if let Some(t) = &target { cmd.args(["--target", t]); }
+                    cmd.current_dir(&p);
+                    println!("[build] plugin {} at {}", name, p.display());
+                    let status = cmd.status().map_err(|e| format!("spawn cargo (plugin {}): {}", name, e))?;
+                    if !status.success() {
+                        return Err(format!("plugin build failed: {} (dir={})", name, p.display()));
+                    }
+                }
+            }
+        }
+        // 4) Build nyash core (features)
+        {
+            let mut cmd = std::process::Command::new("cargo");
+            cmd.arg("build");
+            if profile == "release" { cmd.arg("--release"); }
+            match aot.as_str() { "llvm" => { cmd.args(["--features","llvm"]); }, _ => { cmd.args(["--features","cranelift-jit"]); } }
+            if let Some(t) = &target { cmd.args(["--target", t]); }
+            println!("[build] nyash core ({}, features={})", profile, if aot=="llvm" {"llvm"} else {"cranelift-jit"});
+            let status = cmd.status().map_err(|e| format!("spawn cargo (core): {}", e))?;
+            if !status.success() { return Err("nyash core build failed".into()); }
+        }
+        // 5) Determine app entry
+        let app = if let Some(a) = self.config.build_app.clone() { a } else {
+            // try [build].app, else suggest
+            if let Some(tbl) = doc.get("build").and_then(|v| v.as_table()) {
+                if let Some(s) = tbl.get("app").and_then(|v| v.as_str()) { s.to_string() } else { String::new() }
+            } else { String::new() }
+        };
+        let app = if !app.is_empty() { app } else {
+            // collect candidates under apps/**/main.nyash
+            let mut cand: Vec<String> = Vec::new();
+            fn walk(dir: &Path, acc: &mut Vec<String>) {
+                if let Ok(rd) = std::fs::read_dir(dir) {
+                    for e in rd.flatten() {
+                        let p = e.path();
+                        if p.is_dir() { walk(&p, acc); }
+                        else if p.file_name().map(|n| n=="main.nyash").unwrap_or(false) {
+                            acc.push(p.display().to_string());
+                        }
+                    }
+                }
+            }
+            walk(&cwd.join("apps"), &mut cand);
+            let msg = if cand.is_empty() {
+                "no app specified (--app) and no apps/**/main.nyash found".to_string()
+            } else {
+                format!("no app specified (--app). Candidates:\n  - {}", cand.join("\n  - "))
+            };
+            return Err(msg);
+        };
+        // 6) Emit object
+        let obj_dir = cwd.join("target").join("aot_objects");
+        let _ = std::fs::create_dir_all(&obj_dir);
+        let obj_path = obj_dir.join("main.o");
+        if aot == "llvm" {
+            if std::env::var("LLVM_SYS_180_PREFIX").ok().is_none() && std::env::var("LLVM_SYS_181_PREFIX").ok().is_none() {
+                return Err("LLVM 18 not configured. Set LLVM_SYS_180_PREFIX or install LLVM 18 (llvm-config)".into());
+            }
+            std::env::set_var("NYASH_LLVM_OBJ_OUT", &obj_path);
+            println!("[emit] LLVM object → {}", obj_path.display());
+            let status = std::process::Command::new(cwd.join("target").join(profile.clone()).join(if cfg!(windows) {"nyash.exe"} else {"nyash"}))
+                .args(["--backend","llvm", &app])
+                .status().map_err(|e| format!("spawn nyash llvm: {}", e))?;
+            if !status.success() { return Err("LLVM emit failed".into()); }
+        } else {
+            std::env::set_var("NYASH_AOT_OBJECT_OUT", &obj_dir);
+            println!("[emit] Cranelift object → {} (directory)", obj_dir.display());
+            let status = std::process::Command::new(cwd.join("target").join(profile.clone()).join(if cfg!(windows) {"nyash.exe"} else {"nyash"}))
+                .args(["--backend","vm", &app])
+                .status().map_err(|e| format!("spawn nyash jit-aot: {}", e))?;
+            if !status.success() { return Err("Cranelift emit failed".into()); }
+        }
+        if !obj_path.exists() {
+            // In Cranelift path we produce target/aot_objects/<name>.o; fall back to main.o default
+            if !obj_dir.join("main.o").exists() { return Err(format!("object not generated under {}", obj_dir.display())); }
+        }
+        let out_path = if let Some(o) = out { PathBuf::from(o) } else { if cfg!(windows) { cwd.join("app.exe") } else { cwd.join("app") } };
+        // 7) Link
+        println!("[link] → {}", out_path.display());
+        #[cfg(windows)]
+        {
+            // Prefer MSVC link.exe, then clang fallback
+            if let Ok(link) = which::which("link") {
+                let status = std::process::Command::new(&link).args(["/NOLOGO", &format!("/OUT:{}", out_path.display().to_string())])
+                    .arg(&obj_path)
+                    .arg(cwd.join("target").join("release").join("nyrt.lib"))
+                    .status().map_err(|e| format!("spawn link.exe: {}", e))?;
+                if status.success() { println!("OK"); return Ok(()); }
+            }
+            if let Ok(clang) = which::which("clang") {
+                let status = std::process::Command::new(&clang)
+                    .args(["-o", &out_path.display().to_string(), &obj_path.display().to_string()])
+                    .arg(cwd.join("target").join("release").join("nyrt.lib").display().to_string())
+                    .arg("-lntdll")
+                    .status().map_err(|e| format!("spawn clang: {}", e))?;
+                if status.success() { println!("OK"); return Ok(()); }
+                return Err("link failed on Windows (tried link.exe and clang)".into());
+            }
+            return Err("no linker found (need Visual Studio link.exe or LLVM clang)".into());
+        }
+        #[cfg(not(windows))]
+        {
+            let status = std::process::Command::new("cc")
+                .arg(&obj_path)
+                .args(["-L", &cwd.join("target").join("release").display().to_string()])
+                .args(["-Wl,--whole-archive", "-lnyrt", "-Wl,--no-whole-archive", "-lpthread", "-ldl", "-lm"])
+                .args(["-o", &out_path.display().to_string()])
+                .status().map_err(|e| format!("spawn cc: {}", e))?;
+            if !status.success() { return Err("link failed (cc)".into()); }
+        }
+        println!("✅ Success: {}", out_path.display());
+        Ok(())
+    }
 }
 
 impl NyashRunner {