diff --git a/codegen/build.zig b/codegen/build.zig
index bd0f3ee..4763371 100644
--- a/codegen/build.zig
+++ b/codegen/build.zig
@@ -1,5 +1,8 @@
 const std = @import("std");
 
+// Although this function looks imperative, note that its job is to
+// declaratively construct a build graph that will be executed by an external
+// runner.
 pub fn build(b: *std.build.Builder) !void {
     // Standard target options allows the person running `zig build` to choose
     // what target to build for. Here we do not override the defaults, which
@@ -7,53 +10,65 @@ pub fn build(b: *std.build.Builder) !void {
     // for restricting supported target set are available.
     const target = b.standardTargetOptions(.{});
 
-    // Standard release options allow the person running `zig build` to select
-    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall.
-    const mode = b.standardReleaseOptions();
+    // Standard optimization options allow the person running `zig build` to select
+    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
+    // set a preferred release mode, allowing the user to decide how to optimize.
+    const optimize = b.standardOptimizeOption(.{});
 
-    const exe = b.addExecutable("codegen", "src/main.zig");
-    exe.addPackagePath("smithy", "../smithy/src/smithy.zig");
-    exe.setTarget(target);
-    exe.setBuildMode(mode);
-    // This line works as of c5d412268
-    // Earliest nightly is 05b5e49bc on 2021-06-12
-    // https://ziglang.org/builds/zig-linux-x86_64-0.9.0-dev.113+05b5e49bc.tar.xz
-    // exe.override_dest_dir = .{ .Custom = ".." };
-    exe.override_dest_dir = .{ .custom = ".." };
+    const exe = b.addExecutable(.{
+        .name = "codegen",
+        .root_source_file = .{ .path = "src/main.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
 
-    // Static linkage flag was nonfunctional until 2b2efa24d0855
-    // Did not notice this until 2021-06-28, and that nightly is:
-    // https://ziglang.org/builds/zig-linux-x86_64-0.9.0-dev.321+15a030ef3.tar.xz
-    exe.linkage = .static;
+    const smithy_dep = b.dependency("smithy", .{
+        .target = target,
+        .optimize = optimize,
+    });
+    exe.addModule("smithy", smithy_dep.module("smithy"));
 
-    const is_strip = b.option(bool, "strip", "strip exe") orelse true;
-    exe.strip = !is_strip;
-    exe.install();
+    // This declares intent for the executable to be installed into the
+    // standard location when the user invokes the "install" step (the default
+    // step when running `zig build`).
+    b.installArtifact(exe);
 
-    const run_cmd = exe.run();
+    // This *creates* a Run step in the build graph, to be executed when another
+    // step is evaluated that depends on it. The next line below will establish
+    // such a dependency.
+    const run_cmd = b.addRunArtifact(exe);
+
+    // By making the run step depend on the install step, it will be run from the
+    // installation directory rather than directly from within the cache directory.
+    // This is not necessary, however, if the application depends on other installed
+    // files, this ensures they will be present and in the expected location.
     run_cmd.step.dependOn(b.getInstallStep());
+
+    // This allows the user to pass arguments to the application in the build
+    // command itself, like this: `zig build run -- arg1 arg2 etc`
     if (b.args) |args| {
         run_cmd.addArgs(args);
     }
 
+    // This creates a build step. It will be visible in the `zig build --help` menu,
+    // and can be selected like this: `zig build run`
+    // This will evaluate the `run` step rather than the default, which is "install".
     const run_step = b.step("run", "Run the app");
     run_step.dependOn(&run_cmd.step);
 
-    const test_step = b.step("test", "Run library tests");
-    var src_dir = try std.fs.openDirAbsolute(b.build_root, .{});
-    defer src_dir.close();
-    var iterable = try src_dir.openIterableDir(".", .{});
-    defer iterable.close();
-    var iterator = iterable.iterate();
-    while (try iterator.next()) |entry| {
-        if (std.mem.endsWith(u8, entry.name, ".zig") and
-            !std.mem.eql(u8, entry.name, "main.zig"))
-        {
-            const name = try std.fmt.allocPrint(b.allocator, "src/{s}", .{entry.name});
-            defer b.allocator.free(name);
-            const t = b.addTest(name);
-            t.setBuildMode(mode);
-            test_step.dependOn(&t.step);
-        }
-    }
+    // Creates a step for unit testing. This only builds the test executable
+    // but does not run it.
+    const unit_tests = b.addTest(.{
+        .root_source_file = .{ .path = "src/main.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const run_unit_tests = b.addRunArtifact(unit_tests);
+
+    // Similar to creating the run step earlier, this exposes a `test` step to
+    // the `zig build --help` menu, providing a way for the user to request
+    // running the unit tests.
+    const test_step = b.step("test", "Run unit tests");
+    test_step.dependOn(&run_unit_tests.step);
 }
diff --git a/codegen/build.zig.zon b/codegen/build.zig.zon
new file mode 100644
index 0000000..e7a073c
--- /dev/null
+++ b/codegen/build.zig.zon
@@ -0,0 +1,11 @@
+.{
+    .name = "aws-zig-codegen",
+    .version = "0.0.1",
+
+    .dependencies = .{
+        .smithy = .{
+            .url = "https://git.lerch.org/lobo/smithy/archive/41b61745d25a65817209dd5dddbb5f9b66896a99.tar.gz",
+            .hash = "122087deb0ae309b2258d59b40d82fe5921fdfc35b420bb59033244851f7f276fa34",
+        },
+    },
+}
diff --git a/codegen/src/json.zig b/codegen/src/json.zig
index 2b38b9c..c9ff0ea 100644
--- a/codegen/src/json.zig
+++ b/codegen/src/json.zig
@@ -19,7 +19,7 @@ pub fn serializeMap(map: anytype, key: []const u8, options: anytype, out_stream:
     try out_stream.writeByte('{');
     if (options.whitespace) |_|
         try out_stream.writeByte('\n');
-    for (map) |tag, i| {
+    for (map, 0..) |tag, i| {
         if (tag.key == null or tag.value == null) continue;
         // TODO: Deal with escaping and general "json.stringify" the values...
         if (child_options.whitespace) |ws|
@@ -100,8 +100,8 @@ fn outputUnicodeEscape(
         assert(codepoint <= 0x10FFFF);
         // To escape an extended character that is not in the Basic Multilingual Plane,
         // the character is represented as a 12-character sequence, encoding the UTF-16 surrogate pair.
-        const high = @intCast(u16, (codepoint - 0x10000) >> 10) + 0xD800;
-        const low = @intCast(u16, codepoint & 0x3FF) + 0xDC00;
+        const high = @as(u16, @intCast((codepoint - 0x10000) >> 10)) + 0xD800;
+        const low = @as(u16, @intCast(codepoint & 0x3FF)) + 0xDC00;
         try out_stream.writeAll("\\u");
         try std.fmt.formatIntValue(high, "x", std.fmt.FormatOptions{ .width = 4, .fill = '0' }, out_stream);
         try out_stream.writeAll("\\u");
diff --git a/codegen/src/snake.zig b/codegen/src/snake.zig
index fba9dfa..299d6a3 100644
--- a/codegen/src/snake.zig
+++ b/codegen/src/snake.zig
@@ -72,7 +72,7 @@ fn isAcronymChar(char: u8) bool {
 fn isAscii(codepoint: ?u21) !?u8 {
     if (codepoint) |cp| {
         if (cp > 0xff) return error.UnicodeNotSupported;
-        return @truncate(u8, cp);
+        return @as(u8, @truncate(cp));
     }
     return null;
 }