diff --git a/README.MD b/README.MD
index 5ebca81..abd0430 100644
--- a/README.MD
+++ b/README.MD
@@ -33,6 +33,9 @@ vr run <file.vr|file.vbin>                  compile+link+run, or run a binary
 vr debug <file.vr|file.vbin>                run with an instruction trace
 vr test <file.vr>                           run every test_* function
 vr bench <file.vr> [iterations]             benchmark main()
+vr make [target] [args...]                  run build.vrmm (target = main)
+vr make -f <file.vrmm> [target] [args...]   run another build module
+vr build [target] [args...]                 alias for make
 vr clean                                    remove .vobj/.vbin artifacts
 vr up                                       rebuild bin/vr
 vr symlink                                  link bin/vr into your PATH
@@ -71,6 +74,64 @@ Quick start:
 ./bin/vr run use_lib.vbin
 ```
 
+## Build modules (.vrmm)
+
+A **VuurRaaf Make Module** (`.vrmm`) is build instructions for the toolchain,
+written in VuurRaaf itself — the same idea as V's `.vsh` scripts. The toolchain
+compiles the module and runs one of its functions (a *target*) with the
+`build_*` builtins available, so the script can drive every stage of the
+pipeline: compile, assemble, link, run, test, bench, clean, and shell out to
+the host.
+
+```
+# build.vrmm
+fn main() {
+    build_compile("main.vr", "main.vobj")
+    build_link(["main.vobj"], "main.vbin")
+}
+
+fn clean() {
+    build_clean()
+}
+```
+
+```bash
+vr make              # runs main() from build.vrmm
+vr make clean        # runs the clean() target
+vr make deploy --prod  # runs deploy() with args() == ["--prod"]
+vr make -f x.vrmm t  # run target t from another module
+```
+
+A target that returns a nonzero integer, calls `exit(n)` with `n > 0`, or
+`throw`s fails the build. Paths are relative to the working directory;
+`build_root()` returns the module's own directory for absolute paths.
+
+Build builtins:
+
+| builtin | description |
+|---------|-------------|
+| `build_compile(src, out)` | source → object (out defaults to `src.vobj`); returns the out path |
+| `build_assemble(src, out)` | `.vasm` → object; returns the out path |
+| `build_link(objs, out)` | objects → executable; returns the out path |
+| `build_run(file)` | compile+link+run a `.vr`, or run a `.vbin`; returns the exit code |
+| `build_test(file)` | run every `test_*` function; throws if any fail |
+| `build_bench(file, n)` | benchmark `main()` n times |
+| `build_clean()` | remove `.vobj`/`.vbin` in the cwd; returns the count |
+| `build_exec(cmd)` | run a shell command; returns its output (throws on nonzero exit) |
+| `build_exec_status(cmd)` | run a shell command; returns its exit code |
+| `build_exists(path)` | 1 if the path exists, else 0 |
+| `build_mkdir(path)` | create a directory (and parents) |
+| `build_rm(path)` | remove a file or directory tree; returns 1 if something was removed |
+| `build_copy(src, dst)` | copy a file or a whole directory tree |
+| `build_glob(pattern)` | list files matching a glob (e.g. `"src/*.vr"`) |
+| `build_ls(dir)` | list a directory's entries |
+| `build_base(path)` / `build_dir(path)` / `build_join(a, b)` | path helpers |
+| `build_root()` | absolute directory of the running `.vrmm` |
+
+`vr init` scaffolds a project with a working `build.vrmm`; see
+`examples/build.vrmm` for a tour (targets: `main`, `multi`, `test`, `bench`,
+`deploy`, `clean`).
+
 ## The VuurRaaf language
 
 A small, V-flavored language. Values are 64-bit integers, 64-bit floats,
@@ -261,6 +322,7 @@ main.v               CLI entry point (vr <command> ...)
 repl.v               interactive REPL
 fmt.v                source formatter
 pkg.v                package manager (init/get/install/list)
+vm/native.v          host builtins incl. the build_* (.vrmm) builtins
 v.mod                module definition
 compiler/ assembler/ linker/ vm/ obj/   the toolchain itself
 bin/                 built binary + standalone tools
diff --git a/compiler/check.v b/compiler/check.v
index 6d22f5d..b193ae6 100644
--- a/compiler/check.v
+++ b/compiler/check.v
@@ -552,6 +552,12 @@ fn builtin_result_type(name string) TypeInfo {
 		'args', 'keys' { TypeInfo{ kind: .array_t } }
 		'len' { TypeInfo{ kind: .int_t } }
 		'write_file', 'setenv', 'exit', 'sleep', 'eprint' { TypeInfo{ kind: .unknown } }
+		// build-module builtins (.vrmm)
+		'build_compile', 'build_assemble', 'build_link', 'build_exec', 'build_base',
+		'build_dir', 'build_join', 'build_root' { TypeInfo{ kind: .string_t } }
+		'build_glob', 'build_ls' { TypeInfo{ kind: .array_t } }
+		'build_run', 'build_test', 'build_bench', 'build_clean', 'build_exec_status',
+		'build_exists', 'build_mkdir', 'build_rm', 'build_copy' { TypeInfo{ kind: .int_t } }
 		else { TypeInfo{ kind: .unknown } }
 	}
 }
diff --git a/compiler/codegen.v b/compiler/codegen.v
index 4653267..b73d5d7 100644
--- a/compiler/codegen.v
+++ b/compiler/codegen.v
@@ -903,6 +903,26 @@ fn builtin_spec(name string) (int, int) {
 		'read_file' { native_read_file, 1 }
 		'write_file' { native_write_file, 2 }
 		'eprint' { native_eprint, 1 }
+		// build-module builtins (.vrmm) — see vm/native.v
+		'build_compile' { native_build_compile, 2 }
+		'build_assemble' { native_build_assemble, 2 }
+		'build_link' { native_build_link, 2 }
+		'build_run' { native_build_run, 1 }
+		'build_test' { native_build_test, 1 }
+		'build_bench' { native_build_bench, 2 }
+		'build_clean' { native_build_clean, 0 }
+		'build_exec' { native_build_exec, 1 }
+		'build_exec_status' { native_build_exec_status, 1 }
+		'build_exists' { native_build_exists, 1 }
+		'build_mkdir' { native_build_mkdir, 1 }
+		'build_rm' { native_build_rm, 1 }
+		'build_copy' { native_build_copy, 2 }
+		'build_glob' { native_build_glob, 1 }
+		'build_ls' { native_build_ls, 1 }
+		'build_base' { native_build_base, 1 }
+		'build_dir' { native_build_dir, 1 }
+		'build_join' { native_build_join, 2 }
+		'build_root' { native_build_root, 0 }
 		else { -1, 0 }
 	}
 }
@@ -1131,6 +1151,8 @@ fn (mut g Gen) expr_type(e Expr) string {
 	if e.kind == .call {
 		return match e.name {
 			'upper', 'lower', 'trim', 'str', 'getenv', 'read_file', 'join' { 'string' }
+			'build_compile', 'build_assemble', 'build_link', 'build_exec', 'build_base',
+			'build_dir', 'build_join', 'build_root' { 'string' }
 			else { '' }
 		}
 	}
diff --git a/compiler/opcodes.v b/compiler/opcodes.v
index c30d491..0632579 100644
--- a/compiler/opcodes.v
+++ b/compiler/opcodes.v
@@ -105,3 +105,25 @@ const native_sleep = 134
 const native_read_file = 135
 const native_write_file = 136
 const native_eprint = 137
+
+// build-module builtins (.vrmm) — available to `vr make` scripts and to any
+// program that wants to drive the toolchain
+const native_build_compile = 138
+const native_build_assemble = 139
+const native_build_link = 140
+const native_build_run = 141
+const native_build_test = 142
+const native_build_bench = 143
+const native_build_clean = 144
+const native_build_exec = 145
+const native_build_exec_status = 146
+const native_build_exists = 147
+const native_build_mkdir = 148
+const native_build_rm = 149
+const native_build_copy = 150
+const native_build_glob = 151
+const native_build_ls = 152
+const native_build_base = 153
+const native_build_dir = 154
+const native_build_join = 155
+const native_build_root = 156
diff --git a/examples/build.vrmm b/examples/build.vrmm
new file mode 100644
index 0000000..8c68d24
--- /dev/null
+++ b/examples/build.vrmm
@@ -0,0 +1,55 @@
+// build.vrmm — a VuurRaaf Make Module: build instructions for the toolchain,
+// written in VuurRaaf itself (like V's .vsh, but for this language).
+//
+//   ./bin/vr make -f examples/build.vrmm          build + run hello
+//   ./bin/vr make -f examples/build.vrmm multi    compile/link/run a 2-file program
+//   ./bin/vr make -f examples/build.vrmm test     run tests.vr
+//   ./bin/vr make -f examples/build.vrmm clean    remove artifacts
+//   ./bin/vr make -f examples/build.vrmm deploy --prod    deploy() with args()
+//
+// Paths are relative to the working directory; build_root() returns this
+// module's own directory for scripts that want absolute paths.
+
+fn main() {
+	// compile + link + run in one step
+	build_run("examples/hello.vr")
+}
+
+fn multi() {
+	// drive each toolchain stage explicitly
+	let root = build_root()
+	let lib = build_compile(build_join(root, "lib.vr"), build_join(root, "lib.vobj"))
+	let use = build_compile(build_join(root, "use_lib.vr"), build_join(root, "use_lib.vobj"))
+	let bin = build_link([lib, use], build_join(root, "use_lib.vbin"))
+	build_run(bin)
+}
+
+fn test() {
+	// run every test_* function; fails the build if any test fails
+	build_test("examples/tests.vr")
+}
+
+fn bench() {
+	// benchmark main() of fib.vr 2000 times
+	build_bench("examples/fib.vr", 2000)
+}
+
+fn deploy() {
+	// arguments after the target arrive via args()
+	let args = args()
+	if len(args) == 0 {
+		throw "deploy needs a flag: vr make deploy --prod"
+	}
+	println("deploying with args: " + join(args, " "))
+	let out = build_exec("echo 'deploy step ok'")
+	println(out)
+}
+
+fn clean() {
+	// remove this module's artifacts (build_rm returns 1 if it removed something)
+	let root = build_root()
+	for f in ["lib.vobj", "lib.vbin", "use_lib.vobj", "use_lib.vbin", "hello.vbin"] {
+		build_rm(build_join(root, f))
+	}
+	println("cleaned")
+}
diff --git a/examples/gen_debug.vr b/examples/gen_debug.vr
new file mode 100644
index 0000000..4493de7
--- /dev/null
+++ b/examples/gen_debug.vr
@@ -0,0 +1,9 @@
+// debug: does the function work at all?
+
+fn double(x) {
+    return x * 2
+}
+
+fn main() {
+    println(double(21))
+}
diff --git a/examples/gen_debug2.vr b/examples/gen_debug2.vr
new file mode 100644
index 0000000..65e64ae
--- /dev/null
+++ b/examples/gen_debug2.vr
@@ -0,0 +1,11 @@
+// debug: generic function
+
+fn first[T](arr) {
+    return arr[0]
+}
+
+fn main() {
+    let nums = [10, 20, 30]
+    let x = first(nums)
+    println(x)
+}
diff --git a/examples/gen_debug3.vr b/examples/gen_debug3.vr
new file mode 100644
index 0000000..1d6c1eb
--- /dev/null
+++ b/examples/gen_debug3.vr
@@ -0,0 +1,13 @@
+// debug: trace function execution
+
+fn first[T](arr) {
+    let x = arr[0]
+    println(x)
+    return x
+}
+
+fn main() {
+    let nums = [10, 20, 30]
+    let x = first(nums)
+    println("main got: ${x}")
+}
diff --git a/examples/gen_debug4.vr b/examples/gen_debug4.vr
new file mode 100644
index 0000000..1e511bc
--- /dev/null
+++ b/examples/gen_debug4.vr
@@ -0,0 +1,16 @@
+// debug: trace everything
+
+fn first[T](arr) {
+    println("inside first")
+    println(arr)
+    let x = arr[0]
+    println("x = ${x}")
+    return x
+}
+
+fn main() {
+    println("calling first")
+    let nums = [10, 20, 30]
+    let result = first(nums)
+    println("result = ${result}")
+}
diff --git a/examples/gen_debug5.vr b/examples/gen_debug5.vr
new file mode 100644
index 0000000..07c6903
--- /dev/null
+++ b/examples/gen_debug5.vr
@@ -0,0 +1,12 @@
+// debug: test arr[0] in function body
+
+fn first(arr) {
+    println(arr[0])
+    return arr[0]
+}
+
+fn main() {
+    let nums = [10, 20, 30]
+    let result = first(nums)
+    println("result = ${result}")
+}
diff --git a/examples/gen_debug6.vr b/examples/gen_debug6.vr
new file mode 100644
index 0000000..95bd7b7
--- /dev/null
+++ b/examples/gen_debug6.vr
@@ -0,0 +1,10 @@
+// debug: basic arr[0]
+
+fn get_first(arr) {
+    return arr[0]
+}
+
+fn main() {
+    let nums = [10, 20, 30]
+    println(get_first(nums))
+}
diff --git a/examples/gen_debug7.vr b/examples/gen_debug7.vr
new file mode 100644
index 0000000..5ab75b6
--- /dev/null
+++ b/examples/gen_debug7.vr
@@ -0,0 +1,6 @@
+// debug: inline arr[0]
+
+fn main() {
+    let nums = [10, 20, 30]
+    println(nums[0])
+}
diff --git a/examples/gen_test.vr b/examples/gen_test.vr
new file mode 100644
index 0000000..f3c3f5d
--- /dev/null
+++ b/examples/gen_test.vr
@@ -0,0 +1,10 @@
+// simple generic test
+
+fn first[T](arr) {
+    return arr[0]
+}
+
+fn main() {
+    let nums = [10, 20, 30]
+    println(first[int](nums))
+}
diff --git a/examples/gen_test2.vr b/examples/gen_test2.vr
new file mode 100644
index 0000000..50faf13
--- /dev/null
+++ b/examples/gen_test2.vr
@@ -0,0 +1,10 @@
+// simple generic test - no type args
+
+fn first[T](arr) {
+    return arr[0]
+}
+
+fn main() {
+    let nums = [10, 20, 30]
+    println(first(nums))
+}
diff --git a/main.v b/main.v
index 78fe250..494e77e 100644
--- a/main.v
+++ b/main.v
@@ -91,6 +91,9 @@ fn main() {
 		'clean' {
 			toolchain_clean()
 		}
+		'make', 'm', 'build' {
+			toolchain_make(rest) or { die('make', err) }
+		}
 		'up' {
 			toolchain_up() or { die('up', err) }
 		}
@@ -177,6 +180,9 @@ fn toolchain_help() {
 	println('  get <owner/repo | url | ./path>          fetch a package into vendor/')
 	println('  install                                  install deps from vr.mod')
 	println('  list                                     show the project manifest')
+	println('  make [target] [args...]                  run build.vrmm (target = main)')
+	println('  make -f <file.vrmm> [target] [args...]   run another build module (.vrmm)')
+	println('  build                                    alias for make')
 	println('  clean                                    remove build artifacts')
 	println('  up                                       rebuild the vr binary into bin/')
 	println('  symlink                                  link bin/vr into your PATH')
@@ -468,6 +474,73 @@ fn run_src_with_args(src string, entry string, trace bool, args []string) ! {
 // ---------------------------------------------------------------------------
 // housekeeping
 
+// ---------------------------------------------------------------------------
+// make — run a .vrmm build module
+
+// toolchain_make compiles a .vrmm build module and runs one of its targets.
+// A build module is a VuurRaaf program that drives the toolchain through the
+// build_* builtins (build_compile, build_link, build_run, build_exec, ...).
+//
+//   vr make                 runs main() (or build()) from build.vrmm
+//   vr make clean           runs the clean() target
+//   vr make deploy --prod   runs deploy() with args() == ["--prod"]
+//   vr make -f x.vrmm t     runs target t from x.vrmm
+//
+// A target that returns nonzero (or calls exit(n>0) / throws) fails the build.
+fn toolchain_make(args []string) ! {
+	mut file := 'build.vrmm'
+	mut rest := []string{}
+	mut i := 0
+	for i < args.len {
+		if args[i] == '-f' && i + 1 < args.len {
+			file = args[i + 1]
+			i += 2
+		} else {
+			rest << args[i]
+			i++
+		}
+	}
+	if !os.exists(file) {
+		return error('no build module "${file}" found (write one, or run `vr init` to scaffold it)')
+	}
+	mut target := 'main'
+	if rest.len > 0 {
+		target = rest[0]
+		rest = rest[1..].clone()
+	}
+	// compile and link the build module itself
+	tmp_obj := os.join_path(os.temp_dir(), 'vr_make_${os.getpid()}.vobj')
+	tmp_bin := os.join_path(os.temp_dir(), 'vr_make_${os.getpid()}.vbin')
+	defer {
+		os.rm(tmp_obj) or {}
+		os.rm(tmp_bin) or {}
+	}
+	o := compiler.compile_file(file)!
+	obj.write(tmp_obj, o)!
+	linker.link([tmp_obj], tmp_bin)!
+	bin := obj.read_bin(tmp_bin)!
+	// pick the entry: an explicit target, else main, else build
+	mut names := []string{}
+	for f in bin.fns {
+		names << f.name
+	}
+	mut entry := ''
+	if target == 'main' && 'main' in names {
+		entry = 'main'
+	} else if target == 'main' && 'build' in names {
+		entry = 'build'
+	} else if target in names {
+		entry = target
+	} else {
+		return error('no target function "${target}" in ${file} (available: ${names.join(', ')} or main)')
+	}
+	println('vr make: ${file} [${entry}]')
+	code := vm.run_build(bin, entry, rest, os.abs_path(os.dir(file)))!
+	if code != 0 {
+		return error('target ${entry} finished with exit code ${code}')
+	}
+}
+
 fn toolchain_clean() {
 	mut n := 0
 	if files := os.ls('.') {
diff --git a/pkg.v b/pkg.v
index 6e29901..7482951 100644
--- a/pkg.v
+++ b/pkg.v
@@ -24,7 +24,29 @@ fn toolchain_init(args []string) ! {
 	if !os.exists('main.vr') {
 		os.write_file('main.vr', 'fn main() {\n\tprintln("hello from ${pkg}")\n}\n')!
 	}
-	println('initialized project "${pkg}" (${manifest_file}, main.vr)')
+	if !os.exists('build.vrmm') {
+		os.write_file('build.vrmm', '// build.vrmm — build instructions for the VuurRaaf toolchain.
+//
+//   vr make           runs main()
+//   vr make clean     runs the clean() target
+//
+// Build builtins: build_compile, build_assemble, build_link, build_run,
+// build_test, build_bench, build_clean, build_exec, build_exec_status,
+// build_exists, build_mkdir, build_rm, build_copy, build_glob, build_ls,
+// build_base, build_dir, build_join, build_root.
+
+fn main() {
+	build_compile("main.vr", "main.vobj")
+	build_link(["main.vobj"], "main.vbin")
+	println("built main.vbin — run it with: vr run main.vbin")
+}
+
+fn clean() {
+	build_clean()
+}
+')!
+	}
+	println('initialized project "${pkg}" (${manifest_file}, main.vr, build.vrmm)')
 }
 
 fn toolchain_get(args []string) ! {
diff --git a/vm/native.v b/vm/native.v
index ed09809..fb63a0b 100644
--- a/vm/native.v
+++ b/vm/native.v
@@ -11,6 +11,10 @@ import os
 import math
 import rand
 import time
+import obj
+import compiler
+import assembler
+import linker
 
 fn (mut v Vm) native(id int, _argc int) ! {
 	match id {
@@ -346,12 +350,260 @@ fn (mut v Vm) native(id int, _argc int) ! {
 			x := v.pop()!
 			eprintln(v.val_str(x, 0))
 		}
+		// -------------------------------------------------------------------
+		// build-module builtins (.vrmm) — these let a VuurRaaf program drive
+		// the toolchain itself, the way V's .vsh scripts drive `v build`.
+		native_build_compile {
+			out := v.pop_str()!
+			src := v.pop_str()!
+			o := compiler.compile_file(src) or { return error('build_compile: ${err.msg()}') }
+			o_path := if out.len == 0 { src.all_before_last('.') + '.vobj' } else { out }
+			obj.write(o_path, o) or { return error('build_compile: cannot write ${o_path}: ${err.msg()}') }
+			println('compiled ${src} -> ${o_path} (${o.code.len} bytes code, ${o.symbols.len} symbols)')
+			v.push(v.alloc_str(o_path))!
+		}
+		native_build_assemble {
+			out := v.pop_str()!
+			src := v.pop_str()!
+			o := assembler.assemble_file(src) or { return error('build_assemble: ${err.msg()}') }
+			o_path := if out.len == 0 { src.all_before_last('.') + '.vobj' } else { out }
+			obj.write(o_path, o) or { return error('build_assemble: cannot write ${o_path}: ${err.msg()}') }
+			println('assembled ${src} -> ${o_path} (${o.code.len} bytes code)')
+			v.push(v.alloc_str(o_path))!
+		}
+		native_build_link {
+			out := v.pop_str()!
+			h := v.pop()!
+			if !v.is_arr(h) || !v.valid_arr_handle(h) {
+				return error('build_link() expects an array of object files as its first argument')
+			}
+			mut objs := []string{}
+			for x in v.arrays[v.hand(h)] {
+				if !v.is_str(x) || !v.valid_handle(x) {
+					return error('build_link() expects string paths inside the object array')
+				}
+				objs << v.strings[v.hand(x)]
+			}
+			if objs.len == 0 {
+				return error('build_link() needs at least one object file')
+			}
+			o_path := if out.len == 0 { os.base(objs[0]).all_before_last('.') + '.vbin' } else { out }
+			linker.link(objs, o_path) or { return error('build_link: ${err.msg()}') }
+			println('linked ${objs.len} object file(s) -> ${o_path}')
+			v.push(v.alloc_str(o_path))!
+		}
+		native_build_run {
+			f := v.pop_str()!
+			if f.ends_with('.vbin') {
+				bin := obj.read_bin(f) or { return error('build_run: ${err.msg()}') }
+				code := run_with_args(bin, 'main', false, []string{}) or {
+					return error('build_run: ${err.msg()}')
+				}
+				v.push(v.enc_int(code))!
+				return
+			}
+			if !f.ends_with('.vr') {
+				return error('build_run() expects a .vr or .vbin file')
+			}
+			tmp_obj := os.join_path(os.temp_dir(), 'vr_build_${os.getpid()}.vobj')
+			tmp_bin := os.join_path(os.temp_dir(), 'vr_build_${os.getpid()}.vbin')
+			defer {
+				os.rm(tmp_obj) or {}
+				os.rm(tmp_bin) or {}
+			}
+			o := compiler.compile_file(f) or { return error('build_run: ${err.msg()}') }
+			obj.write(tmp_obj, o) or { return error('build_run: ${err.msg()}') }
+			linker.link([tmp_obj], tmp_bin) or { return error('build_run: ${err.msg()}') }
+			bin := obj.read_bin(tmp_bin) or { return error('build_run: ${err.msg()}') }
+			code := run_with_args(bin, 'main', false, []string{}) or {
+				return error('build_run: ${err.msg()}')
+			}
+			v.push(v.enc_int(code))!
+		}
+		native_build_test {
+			src := v.pop_str()!
+			o := compiler.compile_file(src) or { return error('build_test: ${err.msg()}') }
+			mut tests := []string{}
+			for s in o.symbols {
+				if s.name.starts_with('test_') {
+					tests << s.name
+				}
+			}
+			if tests.len == 0 {
+				return error('build_test: no test_* functions found in ${src}')
+			}
+			tmp_obj := os.join_path(os.temp_dir(), 'vr_build_${os.getpid()}.vobj')
+			tmp_bin := os.join_path(os.temp_dir(), 'vr_build_${os.getpid()}.vbin')
+			defer {
+				os.rm(tmp_obj) or {}
+				os.rm(tmp_bin) or {}
+			}
+			obj.write(tmp_obj, o) or { return error('build_test: ${err.msg()}') }
+			linker.link([tmp_obj], tmp_bin) or { return error('build_test: ${err.msg()}') }
+			bin := obj.read_bin(tmp_bin) or { return error('build_test: ${err.msg()}') }
+			mut passes := 0
+			mut fails := 0
+			for t in tests {
+				run(bin, t, false) or {
+					eprintln('  FAIL  ${t}  —  ${err}')
+					fails++
+					continue
+				}
+				println('  PASS  ${t}')
+				passes++
+			}
+			if fails > 0 {
+				return error('build_test: ${fails} of ${tests.len} test(s) failed in ${src}')
+			}
+			println('${passes} test(s) passed')
+			v.push(v.enc_int(i64(passes)))!
+		}
+		native_build_bench {
+			n := int(v.dec_int(v.pop()!))
+			src := v.pop_str()!
+			if n < 1 {
+				return error('build_bench() expects a positive iteration count')
+			}
+			tmp_obj := os.join_path(os.temp_dir(), 'vr_build_${os.getpid()}.vobj')
+			tmp_bin := os.join_path(os.temp_dir(), 'vr_build_${os.getpid()}.vbin')
+			defer {
+				os.rm(tmp_obj) or {}
+				os.rm(tmp_bin) or {}
+			}
+			o := compiler.compile_file(src) or { return error('build_bench: ${err.msg()}') }
+			obj.write(tmp_obj, o) or { return error('build_bench: ${err.msg()}') }
+			linker.link([tmp_obj], tmp_bin) or { return error('build_bench: ${err.msg()}') }
+			bin := obj.read_bin(tmp_bin) or { return error('build_bench: ${err.msg()}') }
+			start := time.now().unix_milli()
+			for _ in 0..n {
+				run(bin, 'main', false) or { return error('build_bench: ${err.msg()}') }
+			}
+			ms := time.now().unix_milli() - start
+			rate := if ms > 0 { f64(n) / (f64(ms) / 1000.0) } else { f64(0) }
+			println('bench: ${n} runs of main() in ${ms}ms (${rate:.0} runs/s)')
+			v.push(v.enc_int(0))!
+		}
+		native_build_clean {
+			mut n := 0
+			if files := os.ls('.') {
+				for f in files {
+					if f.ends_with('.vobj') || f.ends_with('.vbin') {
+						os.rm(f) or {}
+						n++
+					}
+				}
+			}
+			println('cleaned ${n} artifact(s)')
+			v.push(v.enc_int(i64(n)))!
+		}
+		native_build_exec {
+			cmd := v.pop_str()!
+			res := os.execute(cmd)
+			if res.exit_code != 0 {
+				return error('build_exec: "${cmd}" failed with exit code ${res.exit_code}: ${res.output}')
+			}
+			v.push(v.alloc_str(res.output))!
+		}
+		native_build_exec_status {
+			cmd := v.pop_str()!
+			res := os.execute(cmd)
+			v.push(v.enc_int(i64(res.exit_code)))!
+		}
+		native_build_exists {
+			p := v.pop_str()!
+			v.push(v.enc_int(bool_i64(os.exists(p))))!
+		}
+		native_build_mkdir {
+			p := v.pop_str()!
+			os.mkdir_all(p) or { return error('build_mkdir: cannot create ${p}: ${err.msg()}') }
+			v.push(v.enc_int(0))!
+		}
+		native_build_rm {
+			p := v.pop_str()!
+			if !os.exists(p) {
+				v.push(v.enc_int(0))!
+				return
+			}
+			if os.is_dir(p) {
+				os.rmdir_all(p) or { return error('build_rm: cannot remove ${p}: ${err.msg()}') }
+			} else {
+				os.rm(p) or { return error('build_rm: cannot remove ${p}: ${err.msg()}') }
+			}
+			v.push(v.enc_int(1))!
+		}
+		native_build_copy {
+			dst := v.pop_str()!
+			src := v.pop_str()!
+			if os.is_dir(src) {
+				v.copy_tree(src, dst) or { return error('build_copy: ${err.msg()}') }
+			} else {
+				os.cp(src, dst, os.CopyParams{}) or {
+					return error('build_copy: cannot copy ${src} -> ${dst}: ${err.msg()}')
+				}
+			}
+			v.push(v.enc_int(0))!
+		}
+		native_build_glob {
+			pat := v.pop_str()!
+			files := os.glob(pat) or { return error('build_glob: ${err.msg()}') }
+			mut arr := []i64{}
+			for f in files {
+				v.strings << f
+				arr << v.mkstr(v.strings.len - 1)
+			}
+			v.arrays << arr
+			v.push(v.mkarr(v.arrays.len - 1))!
+		}
+		native_build_ls {
+			dir := v.pop_str()!
+			entries := os.ls(dir) or { return error('build_ls: cannot read ${dir}: ${err.msg()}') }
+			mut arr := []i64{}
+			for f in entries {
+				v.strings << f
+				arr << v.mkstr(v.strings.len - 1)
+			}
+			v.arrays << arr
+			v.push(v.mkarr(v.arrays.len - 1))!
+		}
+		native_build_base {
+			p := v.pop_str()!
+			v.push(v.alloc_str(os.base(p)))!
+		}
+		native_build_dir {
+			p := v.pop_str()!
+			v.push(v.alloc_str(os.dir(p)))!
+		}
+		native_build_join {
+			b := v.pop_str()!
+			a := v.pop_str()!
+			v.push(v.alloc_str(os.join_path(a, b)))!
+		}
+		native_build_root {
+			v.push(v.alloc_str(v.build_root))!
+		}
 		else {
 			return error('unknown native builtin ${id}')
 		}
 	}
 }
 
+// copy_tree recursively copies a directory tree (used by build_copy).
+fn (mut v Vm) copy_tree(src string, dst string) ! {
+	if !os.is_dir(src) {
+		return error('${src} is not a directory')
+	}
+	os.mkdir_all(dst) or { return error('cannot create ${dst}: ${err.msg()}') }
+	for entry in os.ls(src) or { return error('cannot read ${src}: ${err.msg()}') } {
+		sp := os.join_path(src, entry)
+		dp := os.join_path(dst, entry)
+		if os.is_dir(sp) {
+			v.copy_tree(sp, dp)!
+		} else if os.is_file(sp) {
+			os.cp(sp, dp, os.CopyParams{}) or { return error('cannot copy ${sp}: ${err.msg()}') }
+		}
+	}
+}
+
 // pop_str pops the top value and requires it to be a string.
 fn (mut v Vm) pop_str() !string {
 	x := v.pop()!
diff --git a/vm/opcodes.v b/vm/opcodes.v
index 1836d39..27fbbf7 100644
--- a/vm/opcodes.v
+++ b/vm/opcodes.v
@@ -105,3 +105,24 @@ const native_sleep = 134
 const native_read_file = 135
 const native_write_file = 136
 const native_eprint = 137
+
+// build-module builtins (.vrmm) — driven by `vr make`
+const native_build_compile = 138
+const native_build_assemble = 139
+const native_build_link = 140
+const native_build_run = 141
+const native_build_test = 142
+const native_build_bench = 143
+const native_build_clean = 144
+const native_build_exec = 145
+const native_build_exec_status = 146
+const native_build_exists = 147
+const native_build_mkdir = 148
+const native_build_rm = 149
+const native_build_copy = 150
+const native_build_glob = 151
+const native_build_ls = 152
+const native_build_base = 153
+const native_build_dir = 154
+const native_build_join = 155
+const native_build_root = 156
diff --git a/vm/types.v b/vm/types.v
index 19d85de..95978d8 100644
--- a/vm/types.v
+++ b/vm/types.v
@@ -49,6 +49,7 @@ mut:
 	lines     []obj.LineInfo // debug info: code offset -> source line
 	const_strs int          // strings[0..const_strs] are bytecode constants, never collected
 	last_heap  int          // heap size at the last GC check (allocation trigger)
+	build_root string       // directory of the .vrmm build module (build_root() builtin)
 }
 
 fn bool_i64(b bool) i64 {
diff --git a/vm/vm.v b/vm/vm.v
index 837bfea..7b95d34 100644
--- a/vm/vm.v
+++ b/vm/vm.v
@@ -17,6 +17,17 @@ pub fn run(bin obj.Bin, entry string, trace bool) !i64 {
 // run_with_args is run() with command-line arguments exposed to the program
 // via the `args()` builtin.
 pub fn run_with_args(bin obj.Bin, entry string, trace bool, args []string) !i64 {
+	return run_internal(bin, entry, trace, args, '')!
+}
+
+// run_build executes a .vrmm build module: the entry target receives the
+// extra CLI arguments via `args()`, and `build_root()` reports the module's
+// own directory so scripts can find files regardless of the working directory.
+pub fn run_build(bin obj.Bin, entry string, args []string, root string) !i64 {
+	return run_internal(bin, entry, false, args, root)!
+}
+
+fn run_internal(bin obj.Bin, entry string, trace bool, args []string, root string) !i64 {
 	mut v := Vm{
 		code:       bin.code
 		strings:    bin.strings.clone()
@@ -25,6 +36,7 @@ pub fn run_with_args(bin obj.Bin, entry string, trace bool, args []string) !i64
 		prog_args:  args
 		lines:      bin.lines
 		const_strs: bin.strings.len
+		build_root: root
 	}
 	mut entry_ip := -1
 	for f in bin.fns {