diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 94994d4..2f16273 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.67.0"
+  ".": "0.67.1"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9f50ab1..5a9ba83 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## 0.67.1 (2026-06-17)
+
+Full Changelog: [v0.67.0...v0.67.1](https://github.com/smithery-ai/typescript-api/compare/v0.67.0...v0.67.1)
+
+### Bug Fixes
+
+* **client:** send content-type header for requests with an omitted optional body ([50edf0a](https://github.com/smithery-ai/typescript-api/commit/50edf0ad77b4a1d2fce4757102521c009110a0d0))
+
 ## 0.67.0 (2026-05-30)
 
 Full Changelog: [v0.66.0...v0.67.0](https://github.com/smithery-ai/typescript-api/compare/v0.66.0...v0.67.0)
diff --git a/package-lock.json b/package-lock.json
index bcd9591..2556f78 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@smithery/api",
-  "version": "0.67.0",
+  "version": "0.67.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@smithery/api",
-      "version": "0.67.0",
+      "version": "0.67.1",
       "license": "Apache-2.0",
       "devDependencies": {
         "@arethetypeswrong/cli": "^0.17.0",
diff --git a/package.json b/package.json
index 233fad5..4bb0603 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@smithery/api",
-  "version": "0.67.0",
+  "version": "0.67.1",
   "description": "The official TypeScript library for the Smithery API",
   "author": "Smithery <contact@smithery.ai>",
   "types": "dist/index.d.ts",
diff --git a/src/client.ts b/src/client.ts
index 289dbc9..4f3ddca 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -780,11 +780,19 @@ export class Smithery {
     return () => controller.abort();
   }
 
-  private buildBody({ options: { body, headers: rawHeaders } }: { options: FinalRequestOptions }): {
+  private buildBody({ options }: { options: FinalRequestOptions }): {
     bodyHeaders: HeadersLike;
     body: BodyInit | undefined;
   } {
+    const { body, headers: rawHeaders } = options;
     if (!body) {
+      // A resource method always passes a `body` key when its operation defines a
+      // request body, even if the caller omitted an optional body param. Keep the
+      // content-type for those, and only elide it for operations with no body at
+      // all (e.g. GET/DELETE).
+      if (body == null && 'body' in options) {
+        return this.#encoder({ body, headers: buildHeaders([rawHeaders]) });
+      }
       return { bodyHeaders: undefined, body: undefined };
     }
     const headers = buildHeaders([rawHeaders]);
diff --git a/src/version.ts b/src/version.ts
index ed32717..08f9854 100644
--- a/src/version.ts
+++ b/src/version.ts
@@ -1 +1 @@
-export const VERSION = '0.67.0'; // x-release-please-version
+export const VERSION = '0.67.1'; // x-release-please-version