diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..f4e9c15
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1727802920,
+        "narHash": "sha256-HP89HZOT0ReIbI7IJZJQoJgxvB2Tn28V6XS3MNKnfLs=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "27e30d177e57d912d614c88c622dcfdb2e6e6515",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..3247922
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,25 @@
+{
+  description = "A shell environment for building and testing build-tools";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs = { nixpkgs, ... }:
+    let
+      forAllSystems = function:
+        nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed
+          (system: function nixpkgs.legacyPackages.${system});
+    in
+    {
+      formatter = forAllSystems (pkgs: pkgs.alejandra);
+      devShells = forAllSystems (pkgs: {
+        default = pkgs.mkShell {
+          packages = with pkgs; [
+            pnpm
+            nodejs_22
+          ];
+        };
+      });
+    };
+}
diff --git a/src/BuildService.ts b/src/BuildService.ts
index 5aebbb7..c7e360b 100644
--- a/src/BuildService.ts
+++ b/src/BuildService.ts
@@ -286,7 +286,7 @@ export const BuildServiceLive: RTE.ReaderTaskEither<
                     RTE.map(() => file),
                   ),
                 ),
-                RT.chainFirstW(({ left, right }) =>
+                RT.tap(({ left, right }) =>
                   pipe(
                     RT.Do,
                     RT.tap(() =>
@@ -309,38 +309,56 @@ export const BuildServiceLive: RTE.ReaderTaskEither<
             ),
             // Copy `srcDir` files to dist for source maps
             RTE.tap(() =>
-              Files.copyDirectory(
-                config.srcDir,
-                path.join(config.outDir, config.srcDir),
-                { recursive: true },
-              ),
-            ),
-            RTE.tapReaderTask(() =>
-              Log.info(color.magenta('PCK') + color.whiteBright(' Copied source files')),
+              config.emitDeclarationMaps
+                ? pipe(
+                    Files.copyDirectory(
+                      config.srcDir,
+                      path.join(
+                        config.basePath,
+                        config.outDir,
+                        Src.NEW_SOURCE_DIRECTORY,
+                        config.srcDir,
+                      ),
+                      { recursive: true },
+                    ),
+                    RTE.tapReaderTask(() =>
+                      Log.info(
+                        color.magenta('PCK') + color.whiteBright(' Copied source files'),
+                      ),
+                    ),
+                  )
+                : RTE.of(void 0),
             ),
-            // Copy non-`srcDir` entrypoints to dist
+            // Copy non-`srcDir` entrypoints to dist/source-files for source maps
             RTE.tap(() =>
-              pipe(
-                entrypoints,
-                RA.wither(RTE.ApplicativePar)(
-                  (
-                    entrypoint,
-                  ): RTE.ReaderTaskEither<
-                    Files.FileService,
-                    Files.FileServiceError,
-                    O.Option<void>
-                  > =>
-                    rootDirRegex.test(entrypoint)
-                      ? RTE.of(O.none)
-                      : pipe(
-                          Files.copyFile(
-                            entrypoint,
-                            path.join(config.basePath, config.outDir, entrypoint),
-                          ),
-                          RTE.as(O.of(void 0)),
-                        ),
-                ),
-              ),
+              config.emitDeclarationMaps
+                ? pipe(
+                    entrypoints,
+                    RA.wither(RTE.ApplicativePar)(
+                      (
+                        entrypoint,
+                      ): RTE.ReaderTaskEither<
+                        Files.FileService,
+                        Files.FileServiceError,
+                        O.Option<void>
+                      > =>
+                        rootDirRegex.test(entrypoint)
+                          ? RTE.of(O.none)
+                          : pipe(
+                              Files.copyFile(
+                                entrypoint,
+                                path.join(
+                                  config.basePath,
+                                  config.outDir,
+                                  Src.NEW_SOURCE_DIRECTORY,
+                                  entrypoint,
+                                ),
+                              ),
+                              RTE.as(O.of(void 0)),
+                            ),
+                    ),
+                  )
+                : RTE.of(void 0),
             ),
             RTE.tap(() =>
               config.emitTypes
diff --git a/src/ConfigService.ts b/src/ConfigService.ts
index 6e18e2e..65b56b2 100644
--- a/src/ConfigService.ts
+++ b/src/ConfigService.ts
@@ -86,6 +86,15 @@ export type ConfigParameters = {
    */
   readonly srcDir?: string
 
+  /**
+   * Whether to copy the source-directory to "source-files," along with declaration maps.
+   * This allows consumers of the library to control-click in VsCode or go-to-source and
+   * be taken to the raw source of the library.
+   *
+   * @default true
+   */
+  readonly emitDeclarationMaps?: boolean
+
   /**
    * A list of package.json keys to omit from the copied file in dist
    *
@@ -147,11 +156,13 @@ export class ConfigService {
     dtsConfig = 'tsconfig.json',
     dtsCompilerOverrides = {},
     bin = null,
+    emitDeclarationMaps = true,
   }: ConfigParameters) {
     this[ConfigServiceSymbol] = {
       buildType,
       srcDir,
       omittedPackageKeys,
+      emitDeclarationMaps,
       dtsConfig,
       copyFiles,
       basePath,
diff --git a/src/SourceService.ts b/src/SourceService.ts
index 736c83a..a5f33ae 100644
--- a/src/SourceService.ts
+++ b/src/SourceService.ts
@@ -29,12 +29,14 @@ export class SourceService {
   }
 }
 
-function flattenDirByAtLeast1Regex(srcDir: string) {
+function rewriteSourceFolderDropGrandparentDir(srcDir: string) {
   return new RegExp(`(.*)../${srcDir}(.*)`, 'gm')
 }
 
 const rootDirRegex = /^\.\.\/(?!\.\.\/)(.*).(m|c)?ts$/
 
+export const NEW_SOURCE_DIRECTORY = 'source-files'
+
 const rewriteSource: (srcDir: string, file: string) => (source: string) => string =
   (srcDir, file) => source => {
     const fileIsInRootDir = rootDirRegex.test(source)
@@ -42,13 +44,16 @@ const rewriteSource: (srcDir: string, file: string) => (source: string) => strin
     // re-point it to the same directory (dist)
     if (fileIsInRootDir) {
       const basename = path.basename(source)
-      const adjusted = basename.startsWith('.') ? basename : './' + basename
+      const inNewSourceDir = path.join(NEW_SOURCE_DIRECTORY, basename)
+      const adjusted = inNewSourceDir.startsWith('.')
+        ? inNewSourceDir
+        : './' + inNewSourceDir
       return adjusted
       // For other files, re-point the src dir to "."
     } else {
       const flattenedBy1 = `${source}`.replace(
-        flattenDirByAtLeast1Regex(srcDir),
-        `$1${srcDir}$2`,
+        rewriteSourceFolderDropGrandparentDir(srcDir),
+        `$1${NEW_SOURCE_DIRECTORY}/${srcDir}$2`,
       )
       const directory = path.dirname(file)
       const adjusted = path.posix.relative(
diff --git a/src/TypesService.ts b/src/TypesService.ts
index b1693e8..0f1457b 100644
--- a/src/TypesService.ts
+++ b/src/TypesService.ts
@@ -351,7 +351,7 @@ function sharedConfig(
               emitDeclarationOnly: true,
               sourceMap: true,
               declaration: true,
-              declarationMap: true,
+              declarationMap: config.emitDeclarationMaps,
               noEmit: false,
               rootDir: config.basePath,
               outDir: path.join(config.basePath, config.outDir),