diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index bcd0522..5d02000 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.6.0"
+  ".": "0.6.1"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 930b4e9..affcdeb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,19 @@
 # Changelog
 
+## 0.6.1 (2025-06-14)
+
+Full Changelog: [v0.6.0...v0.6.1](https://github.com/gitpod-io/gitpod-sdk-typescript/compare/v0.6.0...v0.6.1)
+
+### Bug Fixes
+
+* publish script — handle NPM errors correctly ([be3283b](https://github.com/gitpod-io/gitpod-sdk-typescript/commit/be3283b4cfb44646b33bf364fb5380d3a226f6a0))
+
+
+### Chores
+
+* **internal:** add pure annotations, make base APIResource abstract ([e489880](https://github.com/gitpod-io/gitpod-sdk-typescript/commit/e48988064ee76b254985960b3c8c7c649d47398e))
+* **internal:** version bump ([94014af](https://github.com/gitpod-io/gitpod-sdk-typescript/commit/94014af9bfcfcf6e676dcc7934687db8704b429f))
+
 ## 0.6.0 (2025-06-06)
 
 Full Changelog: [v0.5.0...v0.6.0](https://github.com/gitpod-io/gitpod-sdk-typescript/compare/v0.5.0...v0.6.0)
diff --git a/bin/publish-npm b/bin/publish-npm
index 2505dec..fa2243d 100644
--- a/bin/publish-npm
+++ b/bin/publish-npm
@@ -7,15 +7,35 @@ npm config set '//registry.npmjs.org/:_authToken' "$NPM_TOKEN"
 yarn build
 cd dist
 
+# Get package name and version from package.json
+PACKAGE_NAME="$(jq -r -e '.name' ./package.json)"
+VERSION="$(jq -r -e '.version' ./package.json)"
+
 # Get latest version from npm
 #
-# If the package doesn't exist, yarn will return
-# {"type":"error","data":"Received invalid response from npm."}
-# where .data.version doesn't exist so LAST_VERSION will be an empty string.
-LAST_VERSION="$(yarn info --json 2> /dev/null | jq -r '.data.version')"
-
-# Get current version from package.json
-VERSION="$(node -p "require('./package.json').version")"
+# If the package doesn't exist, npm will return:
+# {
+#   "error": {
+#     "code": "E404",
+#     "summary": "Unpublished on 2025-06-05T09:54:53.528Z",
+#     "detail": "'the_package' is not in this registry..."
+#   }
+# }
+NPM_INFO="$(npm view "$PACKAGE_NAME" version --json 2>/dev/null || true)"
+
+# Check if we got an E404 error
+if echo "$NPM_INFO" | jq -e '.error.code == "E404"' > /dev/null 2>&1; then
+  # Package doesn't exist yet, no last version
+  LAST_VERSION=""
+elif echo "$NPM_INFO" | jq -e '.error' > /dev/null 2>&1; then
+  # Report other errors
+  echo "ERROR: npm returned unexpected data:"
+  echo "$NPM_INFO"
+  exit 1
+else
+  # Success - get the version
+  LAST_VERSION=$(echo "$NPM_INFO" | jq -r '.') # strip quotes
+fi
 
 # Check if current version is pre-release (e.g. alpha / beta / rc)
 CURRENT_IS_PRERELEASE=false
diff --git a/package.json b/package.json
index 445157f..35f22df 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@gitpod/sdk",
-  "version": "0.6.0",
+  "version": "0.6.1",
   "description": "The official TypeScript library for the Gitpod API",
   "author": "Gitpod <dev-feedback@gitpod.com>",
   "types": "dist/index.d.ts",
@@ -45,7 +45,7 @@
     "sshpk": "^1.18.0",
     "ts-jest": "^29.1.0",
     "ts-node": "^10.5.0",
-    "tsc-multi": "https://github.com/stainless-api/tsc-multi/releases/download/v1.1.4/tsc-multi-1.1.4.tgz",
+    "tsc-multi": "https://github.com/stainless-api/tsc-multi/releases/download/v1.1.7/tsc-multi.tgz",
     "tsconfig-paths": "^4.0.0",
     "typescript": "5.8.3",
     "typescript-eslint": "8.31.1"
diff --git a/scripts/build b/scripts/build
index 1909619..5885b39 100755
--- a/scripts/build
+++ b/scripts/build
@@ -31,7 +31,7 @@ fi
 node scripts/utils/make-dist-package-json.cjs > dist/package.json
 
 # build to .js/.mjs/.d.ts files
-npm exec tsc-multi
+./node_modules/.bin/tsc-multi
 # we need to patch index.js so that `new module.exports()` works for cjs backwards
 # compat. No way to get that from index.ts because it would cause compile errors
 # when building .mjs
diff --git a/src/core/resource.ts b/src/core/resource.ts
index c73b82d..1b226a8 100644
--- a/src/core/resource.ts
+++ b/src/core/resource.ts
@@ -2,7 +2,7 @@
 
 import type { Gitpod } from '../client';
 
-export class APIResource {
+export abstract class APIResource {
   protected _client: Gitpod;
 
   constructor(client: Gitpod) {
diff --git a/src/internal/headers.ts b/src/internal/headers.ts
index 5cc03ce..c724a9d 100644
--- a/src/internal/headers.ts
+++ b/src/internal/headers.ts
@@ -1,5 +1,7 @@
 // File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
+import { isReadonlyArray } from './utils/values';
+
 type HeaderValue = string | undefined | null;
 export type HeadersLike =
   | Headers
@@ -9,7 +11,7 @@ export type HeadersLike =
   | null
   | NullableHeaders;
 
-const brand_privateNullableHeaders = Symbol('brand.privateNullableHeaders');
+const brand_privateNullableHeaders = /* @__PURE__ */ Symbol('brand.privateNullableHeaders');
 
 /**
  * @internal
@@ -25,8 +27,6 @@ export type NullableHeaders = {
   nulls: Set<string>;
 };
 
-const isArray = Array.isArray as (val: unknown) => val is readonly unknown[];
-
 function* iterateHeaders(headers: HeadersLike): IterableIterator<readonly [string, string | null]> {
   if (!headers) return;
 
@@ -43,7 +43,7 @@ function* iterateHeaders(headers: HeadersLike): IterableIterator<readonly [strin
   let iter: Iterable<readonly (HeaderValue | readonly HeaderValue[])[]>;
   if (headers instanceof Headers) {
     iter = headers.entries();
-  } else if (isArray(headers)) {
+  } else if (isReadonlyArray(headers)) {
     iter = headers;
   } else {
     shouldClear = true;
@@ -52,7 +52,7 @@ function* iterateHeaders(headers: HeadersLike): IterableIterator<readonly [strin
   for (let row of iter) {
     const name = row[0];
     if (typeof name !== 'string') throw new TypeError('expected header name to be a string');
-    const values = isArray(row[1]) ? row[1] : [row[1]];
+    const values = isReadonlyArray(row[1]) ? row[1] : [row[1]];
     let didClear = false;
     for (const value of values) {
       if (value === undefined) continue;
diff --git a/src/internal/uploads.ts b/src/internal/uploads.ts
index ef497d7..b9a6090 100644
--- a/src/internal/uploads.ts
+++ b/src/internal/uploads.ts
@@ -90,7 +90,7 @@ export const multipartFormRequestOptions = async (
   return { ...opts, body: await createForm(opts.body, fetch) };
 };
 
-const supportsFormDataMap = new WeakMap<Fetch, Promise<boolean>>();
+const supportsFormDataMap = /** @__PURE__ */ new WeakMap<Fetch, Promise<boolean>>();
 
 /**
  * node-fetch doesn't support the global FormData object in recent node versions. Instead of sending
@@ -138,7 +138,7 @@ export const createForm = async <T = Record<string, unknown>>(
 
 // We check for Blob not File because Bun.File doesn't inherit from File,
 // but they both inherit from Blob and have a `name` property at runtime.
-const isNamedBlob = (value: object) => value instanceof Blob && 'name' in value;
+const isNamedBlob = (value: unknown) => value instanceof Blob && 'name' in value;
 
 const isUploadable = (value: unknown) =>
   typeof value === 'object' &&
diff --git a/src/internal/utils/log.ts b/src/internal/utils/log.ts
index 8fdf60d..dcbf51c 100644
--- a/src/internal/utils/log.ts
+++ b/src/internal/utils/log.ts
@@ -58,7 +58,7 @@ const noopLogger = {
   debug: noop,
 };
 
-let cachedLoggers = new WeakMap<Logger, [LogLevel, Logger]>();
+let cachedLoggers = /** @__PURE__ */ new WeakMap<Logger, [LogLevel, Logger]>();
 
 export function loggerFor(client: Gitpod): Logger {
   const logger = client.logger;
diff --git a/src/internal/utils/path.ts b/src/internal/utils/path.ts
index 56154a2..5800607 100644
--- a/src/internal/utils/path.ts
+++ b/src/internal/utils/path.ts
@@ -60,4 +60,4 @@ export const createPathTagFunction = (pathEncoder = encodeURIPath) =>
 /**
  * URI-encodes path params and ensures no unsafe /./ or /../ path segments are introduced.
  */
-export const path = createPathTagFunction(encodeURIPath);
+export const path = /* @__PURE__ */ createPathTagFunction(encodeURIPath);
diff --git a/src/internal/utils/values.ts b/src/internal/utils/values.ts
index d0e9c61..af2e5ed 100644
--- a/src/internal/utils/values.ts
+++ b/src/internal/utils/values.ts
@@ -9,6 +9,9 @@ export const isAbsoluteURL = (url: string): boolean => {
   return startsWithSchemeRegexp.test(url);
 };
 
+export let isArray = (val: unknown): val is unknown[] => ((isArray = Array.isArray), isArray(val));
+export let isReadonlyArray = isArray as (val: unknown) => val is readonly unknown[];
+
 /** Returns an object if the given value isn't an object, otherwise returns as-is */
 export function maybeObj(x: unknown): object {
   if (typeof x !== 'object') {
diff --git a/src/version.ts b/src/version.ts
index 30c2817..3998d8e 100644
--- a/src/version.ts
+++ b/src/version.ts
@@ -1 +1 @@
-export const VERSION = '0.6.0'; // x-release-please-version
+export const VERSION = '0.6.1'; // x-release-please-version
diff --git a/tsc-multi.json b/tsc-multi.json
index 170bac7..384ddac 100644
--- a/tsc-multi.json
+++ b/tsc-multi.json
@@ -1,7 +1,15 @@
 {
   "targets": [
-    { "extname": ".js", "module": "commonjs", "shareHelpers": "internal/tslib.js" },
-    { "extname": ".mjs", "module": "esnext", "shareHelpers": "internal/tslib.mjs" }
+    {
+      "extname": ".js",
+      "module": "commonjs",
+      "shareHelpers": "internal/tslib.js"
+    },
+    {
+      "extname": ".mjs",
+      "module": "esnext",
+      "shareHelpers": "internal/tslib.mjs"
+    }
   ],
   "projects": ["tsconfig.build.json"]
 }
diff --git a/yarn.lock b/yarn.lock
index a95c3a3..b28a9b6 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3402,9 +3402,9 @@ ts-node@^10.5.0:
     v8-compile-cache-lib "^3.0.0"
     yn "3.1.1"
 
-"tsc-multi@https://github.com/stainless-api/tsc-multi/releases/download/v1.1.4/tsc-multi-1.1.4.tgz":
-  version "1.1.4"
-  resolved "https://github.com/stainless-api/tsc-multi/releases/download/v1.1.4/tsc-multi-1.1.4.tgz#cbed459a9e902f5295ec3daaf1c7aa3b10427e55"
+"tsc-multi@https://github.com/stainless-api/tsc-multi/releases/download/v1.1.7/tsc-multi.tgz":
+  version "1.1.7"
+  resolved "https://github.com/stainless-api/tsc-multi/releases/download/v1.1.7/tsc-multi.tgz#52f40adf8b808bd0b633346d11cc4a8aeea465cd"
   dependencies:
     debug "^4.3.7"
     fast-glob "^3.3.2"