diff --git a/lib/fmt/fmt.ww b/lib/fmt/fmt.ww
index 819485cf..6e0a6178 100644
--- a/lib/fmt/fmt.ww
+++ b/lib/fmt/fmt.ww
@@ -20,27 +20,7 @@
 // via `args...`.
 
 use io;
-
-// Direct rt_syscall / rt_exit bindings rather than `use os;` because
-// os exports read/write/close, which collide with io.read/write/close
-// under the driver's flat-scope concat — same workaround used by
-// lib/memio. Both fmt's fd sink and io.stream sink need to coexist
-// in this module, so the os surface has to come in à la carte.
-@symbol("rt_syscall") fn rtsyscall3(num: i64, a: i64, b: i64, c: i64) i64;
-@symbol("rt_syscall") fn rtsyscall1(num: i64, a: i64) i64;
-
-// rawwrite — Linux write(2) syscall (nr=1). The fd sinks below call
-// this directly instead of [[os.write]] to keep the collision off
-// fmt's exported surface. Same signature, same negative-errno
-// convention.
-fn rawwrite(fd: i32, buf: *u8, n: u64) i64 = {
-	return rtsyscall3(1i64, fd: i64, buf: i64, n: i64);
-};
-
-// rawexit — Linux exit(2) syscall (nr=60). Used only by `fatal`.
-fn rawexit(code: i32) void = {
-	rtsyscall1(60i64, code: i64);
-};
+use os;
 
 // i64dec_buf — scratch buffer for [[i64dec]] below. Module-level
 // because Hare's `strconv::i64tos` is a static-buffer view and we
@@ -102,33 +82,33 @@ export fn fdprint(fd: i32, args: formattable...) i64 = {
 	let i: i32 = 0;
 	for (i < args.len) {
 		if (i > 0) {
-			let r: i64 = rawwrite(fd, " ".ptr, 1u64);
+			let r: i64 = os.write(fd, " ".ptr, 1u64);
 			if (r < 0) { return r; };
 			total += r;
 		};
 		match (args[i]) {
 		case let n: i64 => {
 			let s: str = i64dec(n);
-			let r: i64 = rawwrite(fd, s.ptr, s.len: u64);
+			let r: i64 = os.write(fd, s.ptr, s.len: u64);
 			if (r < 0) { return r; };
 			total += r;
 		};
 		case let s: str => {
-			let r: i64 = rawwrite(fd, s.ptr, s.len: u64);
+			let r: i64 = os.write(fd, s.ptr, s.len: u64);
 			if (r < 0) { return r; };
 			total += r;
 		};
 		case let b: bool => {
 			let s: str = "false";
 			if (b) { s = "true"; };
-			let r: i64 = rawwrite(fd, s.ptr, s.len: u64);
+			let r: i64 = os.write(fd, s.ptr, s.len: u64);
 			if (r < 0) { return r; };
 			total += r;
 		};
 		case let r: rune => {
 			let buf: [4]u8;
 			buf[0] = r: u8;
-			let n: i64 = rawwrite(fd, &buf[0], 1u64);
+			let n: i64 = os.write(fd, &buf[0], 1u64);
 			if (n < 0) { return n; };
 			total += n;
 		};
@@ -142,7 +122,7 @@ export fn fdprint(fd: i32, args: formattable...) i64 = {
 export fn fdprintln(fd: i32, args: formattable...) i64 = {
 	let n: i64 = fdprint(fd, args...);
 	if (n < 0) { return n; };
-	let m: i64 = rawwrite(fd, "\n".ptr, 1u64);
+	let m: i64 = os.write(fd, "\n".ptr, 1u64);
 	if (m < 0) { return m; };
 	return n + m;
 };
@@ -267,5 +247,5 @@ export fn errorln(args: formattable...) i64 = {
 // follows immediately).
 export fn fatal(args: formattable...) never = {
 	fdprintln(2, args...);
-	rawexit(255);
+	os.exit(255);
 };
diff --git a/lib/log/log.ww b/lib/log/log.ww
index 1354e095..09ce07fb 100644
--- a/lib/log/log.ww
+++ b/lib/log/log.ww
@@ -39,13 +39,8 @@
 //
 // Sink today is [[io.stream]] only — lib/io has no fd-backed stream
 // yet (Hare's `io::handle = file | int` collapses to one variant).
-// The default logger writes to stderr via a private io.stream that
-// dispatches through an rt_syscall write callback; mirrors lib/fmt's
-// defensive `rawwrite` / `rawexit` shape for the same C-symbol
-// collision reason (lib/os and lib/io both export `write`/`read`/
-// `close`, and `use os;` from log would re-trip #17). Both fmt and
-// log drop their rt_syscall stubs in one cleanup commit once #17
-// (cgen module-mangling of fn labels) lands.
+// The default logger writes to stderr via a private io.stream whose
+// write callback forwards to [[os.write]] on fd 2.
 //
 // Compiler note: wwstage cgen's variadic dispatch is name-based
 // (`fnparamslookup(callee.str)`), which would conflate the
@@ -74,25 +69,7 @@
 
 use fmt;
 use io;
-
-// Direct rt_syscall bindings rather than `use os;` — os exports
-// read/write/close, which collide with io.read/write/close under the
-// driver's flat-scope concat. Mirrors lib/fmt and lib/memio. Removed
-// once #17 (cgen mod-mangle for fn labels) lands.
-@symbol("rt_syscall") fn rtsyscall3(num: i64, a: i64, b: i64, c: i64) i64;
-@symbol("rt_syscall") fn rtsyscall1(num: i64, a: i64) i64;
-
-// rawwrite — Linux write(2) syscall (nr=1). Private stderr sink uses
-// this so log's exported surface stays clear of the os.write symbol.
-fn rawwrite(fd: i32, p: *u8, n: u64) i64 = {
-	return rtsyscall3(1i64, fd: i64, p: i64, n: i64);
-};
-
-// rawexit — Linux exit(2) syscall (nr=60). Used by [[fatal]] and
-// [[lfatal]] for the process-terminating arm.
-fn rawexit(code: i32) void = {
-	rtsyscall1(60i64, code: i64);
-};
+use os;
 
 // logger — interface for log dispatch. v1 carries a single vtable
 // slot. Hare layers a `printfln` slot for format-string callbacks;
@@ -115,10 +92,10 @@ export type stdlogger = struct {
 	sink:   *io.stream,
 };
 
-// stderrsink — private io.stream wired through the raw stderr fd (2)
-// via [[rawwrite]]. Used as [[default]]'s sink. Independent of lib/io's
-// future fd-backed stream — when that lands, this collapses to a
-// thin wrapper and graduates in one go.
+// stderrsink — private io.stream wired through fd 2 via [[os.write]].
+// Used as [[default]]'s sink. Independent of lib/io's future fd-backed
+// stream — when that lands, this collapses to a thin wrapper and
+// graduates in one go.
 let stderrsink: io.stream;
 
 // _silent — backing storage for the [[silent]] global.
@@ -167,7 +144,7 @@ fn stderrread(s: *io.stream, buf: []u8) (i32 | io.eof | io.closed) = {
 };
 
 fn stderrwrite(s: *io.stream, buf: []u8) (i32 | io.closed) = {
-	let r: i64 = rawwrite(2, buf.ptr, buf.len: u64);
+	let r: i64 = os.write(2, buf.ptr, buf.len: u64);
 	if (r < 0) {
 		let e: io.closed;
 		return e;
@@ -218,14 +195,14 @@ export fn println(args: fmt.formattable...) void = {
 // Hare's lib/log/funcs.ha counterpart at line 28.
 export fn lfatal(log: *logger, args: fmt.formattable...) never = {
 	lprintln(log, args...);
-	rawexit(255);
+	os.exit(255);
 };
 
 // fatal — lprintln to [[global]] then exit(255). Hare's lib/log/
 // funcs.ha counterpart at line 45.
 export fn fatal(args: fmt.formattable...) never = {
 	println(args...);
-	rawexit(255);
+	os.exit(255);
 };
 
 // setlogger — install `log` as the [[global]] logger. Hare's