diff --git a/dist/index.d.mts b/dist/index.d.mts
index 266c5ffdd9ee74ff95908ce90858ee4369d4e4ae..990ef4195bc67b6d25f249e1c81cf51710390f9a 100644
--- a/dist/index.d.mts
+++ b/dist/index.d.mts
@@ -78,6 +78,7 @@ declare const xaiLanguageModelResponsesOptions: z.ZodObject<{
     topLogprobs: z.ZodOptional<z.ZodNumber>;
     store: z.ZodOptional<z.ZodBoolean>;
     previousResponseId: z.ZodOptional<z.ZodString>;
+    promptCacheKey: z.ZodOptional<z.ZodString>;
     include: z.ZodOptional<z.ZodNullable<z.ZodArray<z.ZodEnum<{
         "file_search_call.results": "file_search_call.results";
     }>>>>;
diff --git a/dist/index.d.ts b/dist/index.d.ts
index 266c5ffdd9ee74ff95908ce90858ee4369d4e4ae..990ef4195bc67b6d25f249e1c81cf51710390f9a 100644
--- a/dist/index.d.ts
+++ b/dist/index.d.ts
@@ -78,6 +78,7 @@ declare const xaiLanguageModelResponsesOptions: z.ZodObject<{
     topLogprobs: z.ZodOptional<z.ZodNumber>;
     store: z.ZodOptional<z.ZodBoolean>;
     previousResponseId: z.ZodOptional<z.ZodString>;
+    promptCacheKey: z.ZodOptional<z.ZodString>;
     include: z.ZodOptional<z.ZodNullable<z.ZodArray<z.ZodEnum<{
         "file_search_call.results": "file_search_call.results";
     }>>>>;
diff --git a/dist/index.js b/dist/index.js
index 717b74538f5c8f0d6ab1475ebb2a84a47ccd3950..dd7dbeb3bc307e0d355f4bb4939d06cc8eae7528 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -1119,6 +1119,14 @@ async function convertToXaiResponsesInput({
                   type: "input_file",
                   file_url: block.data.toString()
                 });
+              } else if (block.mediaType === "application/pdf") {
+                contentParts.push({
+                  type: "input_file",
+                  ...typeof block.data === "string" && block.data.startsWith("file-") ? { file_id: block.data } : {
+                    filename: block.filename ?? "file",
+                    file_data: `data:application/pdf;base64,${(0, import_provider_utils5.convertToBase64)(block.data)}`
+                  }
+                });
               } else {
                 throw new import_provider4.UnsupportedFunctionalityError({
                   functionality: `file part media type ${block.mediaType} as inline data (xAI Responses requires a URL or a Files API reference for non-image files)`
@@ -1760,6 +1768,10 @@ var xaiLanguageModelResponsesOptions = import_v47.z.object({
    * The ID of the previous response from the model.
    */
   previousResponseId: import_v47.z.string().optional(),
+  /**
+   * A stable key used by xAI to improve prompt cache routing.
+   */
+  promptCacheKey: import_v47.z.string().optional(),
   /**
    * Specify additional output data to include in the model response.
    * Example values: 'file_search_call.results'.
@@ -2165,6 +2177,9 @@ var XaiResponsesLanguageModel = class {
       },
       ...options.previousResponseId != null && {
         previous_response_id: options.previousResponseId
+      },
+      ...options.promptCacheKey != null && {
+        prompt_cache_key: options.promptCacheKey
       }
     };
     if (xaiTools2 && xaiTools2.length > 0) {
diff --git a/dist/index.mjs b/dist/index.mjs
index a26af109585fc2bd3053b320142aa869c06d36f4..774adaf971b648544317a4fc65d0c56e488d4fc7 100644
--- a/dist/index.mjs
+++ b/dist/index.mjs
@@ -1122,6 +1122,14 @@ async function convertToXaiResponsesInput({
                   type: "input_file",
                   file_url: block.data.toString()
                 });
+              } else if (block.mediaType === "application/pdf") {
+                contentParts.push({
+                  type: "input_file",
+                  ...typeof block.data === "string" && block.data.startsWith("file-") ? { file_id: block.data } : {
+                    filename: block.filename ?? "file",
+                    file_data: `data:application/pdf;base64,${convertToBase642(block.data)}`
+                  }
+                });
               } else {
                 throw new UnsupportedFunctionalityError3({
                   functionality: `file part media type ${block.mediaType} as inline data (xAI Responses requires a URL or a Files API reference for non-image files)`
@@ -1763,6 +1771,10 @@ var xaiLanguageModelResponsesOptions = z7.object({
    * The ID of the previous response from the model.
    */
   previousResponseId: z7.string().optional(),
+  /**
+   * A stable key used by xAI to improve prompt cache routing.
+   */
+  promptCacheKey: z7.string().optional(),
   /**
    * Specify additional output data to include in the model response.
    * Example values: 'file_search_call.results'.
@@ -2186,6 +2198,9 @@ var XaiResponsesLanguageModel = class {
       },
       ...options.previousResponseId != null && {
         previous_response_id: options.previousResponseId
+      },
+      ...options.promptCacheKey != null && {
+        prompt_cache_key: options.promptCacheKey
       }
     };
     if (xaiTools2 && xaiTools2.length > 0) {
diff --git a/src/responses/convert-to-xai-responses-input.ts b/src/responses/convert-to-xai-responses-input.ts
index 9a3712990cf646a6f7ba757d3f2893a3c37c6ef9..b018a9b95eb21e6c12794e6bddb3d953f40441e5 100644
--- a/src/responses/convert-to-xai-responses-input.ts
+++ b/src/responses/convert-to-xai-responses-input.ts
@@ -64,6 +64,17 @@ export async function convertToXaiResponsesInput({
                   type: 'input_file',
                   file_url: block.data.toString(),
                 });
+              } else if (block.mediaType === 'application/pdf') {
+                contentParts.push({
+                  type: 'input_file',
+                  ...(typeof block.data === 'string' &&
+                  block.data.startsWith('file-')
+                    ? { file_id: block.data }
+                    : {
+                        filename: block.filename ?? 'file',
+                        file_data: `data:application/pdf;base64,${convertToBase64(block.data)}`,
+                      }),
+                });
               } else {
                 throw new UnsupportedFunctionalityError({
                   functionality: `file part media type ${block.mediaType} as inline data (xAI Responses requires a URL or a Files API reference for non-image files)`,
diff --git a/src/responses/xai-responses-api.ts b/src/responses/xai-responses-api.ts
index 70483ea4f7c340b84c23766ac1d1df21e052842b..4b4d052860caa019556151e9e46dbfda8dfb18a9 100644
--- a/src/responses/xai-responses-api.ts
+++ b/src/responses/xai-responses-api.ts
@@ -27,7 +27,13 @@ export type XaiResponsesSystemMessage = {
 export type XaiResponsesUserMessageContentPart =
   | { type: 'input_text'; text: string }
   | { type: 'input_image'; image_url: string }
-  | { type: 'input_file'; file_url: string };
+  | {
+      type: 'input_file';
+      file_url?: string;
+      file_id?: string;
+      file_data?: string;
+      filename?: string;
+    };
 
 export type XaiResponsesUserMessage = {
   role: 'user';
diff --git a/src/responses/xai-responses-language-model.ts b/src/responses/xai-responses-language-model.ts
index f90df62eb9a30154388b1390e9f3acc3ccc022bf..00e61cba6cf048ae0045be692f33cb7e1e6a1188 100644
--- a/src/responses/xai-responses-language-model.ts
+++ b/src/responses/xai-responses-language-model.ts
@@ -182,6 +182,9 @@ export class XaiResponsesLanguageModel implements LanguageModelV3 {
       ...(options.previousResponseId != null && {
         previous_response_id: options.previousResponseId,
       }),
+      ...(options.promptCacheKey != null && {
+        prompt_cache_key: options.promptCacheKey,
+      }),
     };
 
     if (xaiTools && xaiTools.length > 0) {
diff --git a/src/responses/xai-responses-options.ts b/src/responses/xai-responses-options.ts
index f8e96c061bf8793a402ababb8cad65bb2ad6aead..15c168892c1e8755453c61d3061e958cfd51ac71 100644
--- a/src/responses/xai-responses-options.ts
+++ b/src/responses/xai-responses-options.ts
@@ -32,6 +32,10 @@ export const xaiLanguageModelResponsesOptions = z.object({
    * The ID of the previous response from the model.
    */
   previousResponseId: z.string().optional(),
+  /**
+   * A stable key used by xAI to improve prompt cache routing.
+   */
+  promptCacheKey: z.string().optional(),
   /**
    * Specify additional output data to include in the model response.
    * Example values: 'file_search_call.results'.