diff --git a/scripts/fix-index-exports.cjs b/scripts/fix-index-exports.cjs
index 0909af7c..b61b2ea3 100644
--- a/scripts/fix-index-exports.cjs
+++ b/scripts/fix-index-exports.cjs
@@ -1,7 +1,11 @@
 const fs = require('fs');
 const path = require('path');
 
-const indexJs = path.resolve(__dirname, '..', 'dist', 'index.js');
+const indexJs =
+  process.env['DIST_PATH'] ?
+    path.resolve(process.env['DIST_PATH'], 'index.js')
+  : path.resolve(__dirname, '..', 'dist', 'index.js');
+
 let before = fs.readFileSync(indexJs, 'utf8');
 let after = before.replace(
   /^\s*exports\.default\s*=\s*(\w+)/m,
diff --git a/scripts/make-dist-package-json.cjs b/scripts/make-dist-package-json.cjs
index def768ed..d4a0a69b 100644
--- a/scripts/make-dist-package-json.cjs
+++ b/scripts/make-dist-package-json.cjs
@@ -1,4 +1,4 @@
-const pkgJson = require('../package.json');
+const pkgJson = require(process.env['PKG_JSON_PATH'] || '../package.json');
 
 function processExportMap(m) {
   for (const key in m) {
diff --git a/scripts/postprocess-files.cjs b/scripts/postprocess-files.cjs
index f990dbc5..cbe266dc 100644
--- a/scripts/postprocess-files.cjs
+++ b/scripts/postprocess-files.cjs
@@ -2,7 +2,12 @@ const fs = require('fs');
 const path = require('path');
 const { parse } = require('@typescript-eslint/parser');
 
-const distDir = path.resolve(__dirname, '..', 'dist');
+const pkgImportPath = process.env['PKG_IMPORT_PATH'] ?? '@anthropic-ai/sdk/'
+
+const distDir =
+  process.env['DIST_PATH'] ?
+    path.resolve(process.env['DIST_PATH'])
+  : path.resolve(__dirname, '..', 'dist');
 const distSrcDir = path.join(distDir, 'src');
 
 /**
@@ -105,11 +110,11 @@ async function postprocess() {
 
     let transformed = mapModulePaths(code, (importPath) => {
       if (file.startsWith(distSrcDir)) {
-        if (importPath.startsWith('@anthropic-ai/sdk/')) {
+        if (importPath.startsWith(pkgImportPath)) {
           // convert self-references in dist/src to relative paths
           let relativePath = path.relative(
             path.dirname(file),
-            path.join(distSrcDir, importPath.substring('@anthropic-ai/sdk/'.length)),
+            path.join(distSrcDir, importPath.substring(pkgImportPath.length)),
           );
           if (!relativePath.startsWith('.')) relativePath = `./${relativePath}`;
           return relativePath;
diff --git a/src/core.ts b/src/core.ts
index 756d7bc3..404e9b01 100644
--- a/src/core.ts
+++ b/src/core.ts
@@ -342,6 +342,11 @@ export abstract class APIClient {
     return reqHeaders;
   }
 
+  /**
+   * Used as a callback for mutating the given `FinalRequestOptions` object.
+   */
+  protected async prepareOptions(options: FinalRequestOptions): Promise<void> {}
+
   /**
    * Used as a callback for mutating the given `RequestInit` object.
    *
@@ -387,6 +392,8 @@ export abstract class APIClient {
       retriesRemaining = options.maxRetries ?? this.maxRetries;
     }
 
+    await this.prepareOptions(options);
+
     const { req, url, timeout } = this.buildRequest(options);
 
     await this.prepareRequest(req, { url, options });
@@ -1139,3 +1146,7 @@ export const toBase64 = (str: string | null | undefined): string => {
 
   throw new AnthropicError('Cannot generate b64 string; Expected `Buffer` or `btoa` to be defined');
 };
+
+export function isObj(obj: unknown): obj is Record<string, unknown> {
+  return obj != null && typeof obj === 'object' && !Array.isArray(obj);
+}