diff --git a/src/lib/BetaMessageStream.ts b/src/lib/BetaMessageStream.ts
index 2baa482a..5de54f06 100644
--- a/src/lib/BetaMessageStream.ts
+++ b/src/lib/BetaMessageStream.ts
@@ -9,6 +9,7 @@ import {
   type MessageCreateParams as BetaMessageCreateParams,
   type MessageCreateParamsBase as BetaMessageCreateParamsBase,
   type BetaTextBlock,
+  type BetaTextCitation,
 } from '@anthropic-ai/sdk/resources/beta/messages/messages';
 import { type ReadableStream, type Response } from '@anthropic-ai/sdk/_shims/index';
 import { Stream } from '@anthropic-ai/sdk/streaming';
@@ -18,6 +19,7 @@ export interface MessageStreamEvents {
   connect: () => void;
   streamEvent: (event: BetaMessageStreamEvent, snapshot: BetaMessage) => void;
   text: (textDelta: string, textSnapshot: string) => void;
+  citation: (citation: BetaTextCitation, citationsSnapshot: BetaTextCitation[]) => void;
   inputJson: (partialJson: string, jsonSnapshot: unknown) => void;
   message: (message: BetaMessage) => void;
   contentBlock: (content: BetaContentBlock) => void;
@@ -413,12 +415,27 @@ export class BetaMessageStream implements AsyncIterable<BetaMessageStreamEvent>
     switch (event.type) {
       case 'content_block_delta': {
         const content = messageSnapshot.content.at(-1)!;
-        if (event.delta.type === 'text_delta' && content.type === 'text') {
-          this._emit('text', event.delta.text, content.text || '');
-        } else if (event.delta.type === 'input_json_delta' && content.type === 'tool_use') {
-          if (content.input) {
-            this._emit('inputJson', event.delta.partial_json, content.input);
+        switch (event.delta.type) {
+          case 'text_delta': {
+            if (content.type === 'text') {
+              this._emit('text', event.delta.text, content.text || '');
+            }
+            break;
           }
+          case 'citations_delta': {
+            if (content.type === 'text') {
+              this._emit('citation', event.delta.citation, content.citations ?? []);
+            }
+            break;
+          }
+          case 'input_json_delta': {
+            if (content.type === 'tool_use' && content.input) {
+              this._emit('inputJson', event.delta.partial_json, content.input);
+            }
+            break;
+          }
+          default:
+            checkNever(event.delta);
         }
         break;
       }
@@ -505,24 +522,43 @@ export class BetaMessageStream implements AsyncIterable<BetaMessageStreamEvent>
         return snapshot;
       case 'content_block_delta': {
         const snapshotContent = snapshot.content.at(event.index);
-        if (snapshotContent?.type === 'text' && event.delta.type === 'text_delta') {
-          snapshotContent.text += event.delta.text;
-        } else if (snapshotContent?.type === 'tool_use' && event.delta.type === 'input_json_delta') {
-          // we need to keep track of the raw JSON string as well so that we can
-          // re-parse it for each delta, for now we just store it as an untyped
-          // non-enumerable property on the snapshot
-          let jsonBuf = (snapshotContent as any)[JSON_BUF_PROPERTY] || '';
-          jsonBuf += event.delta.partial_json;
-
-          Object.defineProperty(snapshotContent, JSON_BUF_PROPERTY, {
-            value: jsonBuf,
-            enumerable: false,
-            writable: true,
-          });
-
-          if (jsonBuf) {
-            snapshotContent.input = partialParse(jsonBuf);
+
+        switch (event.delta.type) {
+          case 'text_delta': {
+            if (snapshotContent?.type === 'text') {
+              snapshotContent.text += event.delta.text;
+            }
+            break;
           }
+          case 'citations_delta': {
+            if (snapshotContent?.type === 'text') {
+              snapshotContent.citations ??= [];
+              snapshotContent.citations.push(event.delta.citation);
+            }
+            break;
+          }
+          case 'input_json_delta': {
+            if (snapshotContent?.type === 'tool_use') {
+              // we need to keep track of the raw JSON string as well so that we can
+              // re-parse it for each delta, for now we just store it as an untyped
+              // non-enumerable property on the snapshot
+              let jsonBuf = (snapshotContent as any)[JSON_BUF_PROPERTY] || '';
+              jsonBuf += event.delta.partial_json;
+
+              Object.defineProperty(snapshotContent, JSON_BUF_PROPERTY, {
+                value: jsonBuf,
+                enumerable: false,
+                writable: true,
+              });
+
+              if (jsonBuf) {
+                snapshotContent.input = partialParse(jsonBuf);
+              }
+            }
+            break;
+          }
+          default:
+            checkNever(event.delta);
         }
         return snapshot;
       }
@@ -597,3 +633,6 @@ export class BetaMessageStream implements AsyncIterable<BetaMessageStreamEvent>
     return stream.toReadableStream();
   }
 }
+
+// used to ensure exhaustive case matching without throwing a runtime error
+function checkNever(x: never) {}
diff --git a/src/lib/MessageStream.ts b/src/lib/MessageStream.ts
index b47cded0..4ce3a382 100644
--- a/src/lib/MessageStream.ts
+++ b/src/lib/MessageStream.ts
@@ -9,6 +9,7 @@ import {
   type MessageCreateParams,
   type MessageCreateParamsBase,
   type TextBlock,
+  type TextCitation,
 } from '@anthropic-ai/sdk/resources/messages';
 import { type ReadableStream, type Response } from '@anthropic-ai/sdk/_shims/index';
 import { Stream } from '@anthropic-ai/sdk/streaming';
@@ -18,6 +19,7 @@ export interface MessageStreamEvents {
   connect: () => void;
   streamEvent: (event: MessageStreamEvent, snapshot: Message) => void;
   text: (textDelta: string, textSnapshot: string) => void;
+  citation: (citation: TextCitation, citationsSnapshot: TextCitation[]) => void;
   inputJson: (partialJson: string, jsonSnapshot: unknown) => void;
   message: (message: Message) => void;
   contentBlock: (content: ContentBlock) => void;
@@ -413,12 +415,27 @@ export class MessageStream implements AsyncIterable<MessageStreamEvent> {
     switch (event.type) {
       case 'content_block_delta': {
         const content = messageSnapshot.content.at(-1)!;
-        if (event.delta.type === 'text_delta' && content.type === 'text') {
-          this._emit('text', event.delta.text, content.text || '');
-        } else if (event.delta.type === 'input_json_delta' && content.type === 'tool_use') {
-          if (content.input) {
-            this._emit('inputJson', event.delta.partial_json, content.input);
+        switch (event.delta.type) {
+          case 'text_delta': {
+            if (content.type === 'text') {
+              this._emit('text', event.delta.text, content.text || '');
+            }
+            break;
           }
+          case 'citations_delta': {
+            if (content.type === 'text') {
+              this._emit('citation', event.delta.citation, content.citations ?? []);
+            }
+            break;
+          }
+          case 'input_json_delta': {
+            if (content.type === 'tool_use' && content.input) {
+              this._emit('inputJson', event.delta.partial_json, content.input);
+            }
+            break;
+          }
+          default:
+            checkNever(event.delta);
         }
         break;
       }
@@ -505,25 +522,45 @@ export class MessageStream implements AsyncIterable<MessageStreamEvent> {
         return snapshot;
       case 'content_block_delta': {
         const snapshotContent = snapshot.content.at(event.index);
-        if (snapshotContent?.type === 'text' && event.delta.type === 'text_delta') {
-          snapshotContent.text += event.delta.text;
-        } else if (snapshotContent?.type === 'tool_use' && event.delta.type === 'input_json_delta') {
-          // we need to keep track of the raw JSON string as well so that we can
-          // re-parse it for each delta, for now we just store it as an untyped
-          // non-enumerable property on the snapshot
-          let jsonBuf = (snapshotContent as any)[JSON_BUF_PROPERTY] || '';
-          jsonBuf += event.delta.partial_json;
-
-          Object.defineProperty(snapshotContent, JSON_BUF_PROPERTY, {
-            value: jsonBuf,
-            enumerable: false,
-            writable: true,
-          });
-
-          if (jsonBuf) {
-            snapshotContent.input = partialParse(jsonBuf);
+
+        switch (event.delta.type) {
+          case 'text_delta': {
+            if (snapshotContent?.type === 'text') {
+              snapshotContent.text += event.delta.text;
+            }
+            break;
+          }
+          case 'citations_delta': {
+            if (snapshotContent?.type === 'text') {
+              snapshotContent.citations ??= [];
+              snapshotContent.citations.push(event.delta.citation);
+            }
+            break;
           }
+          case 'input_json_delta': {
+            if (snapshotContent?.type === 'tool_use') {
+              // we need to keep track of the raw JSON string as well so that we can
+              // re-parse it for each delta, for now we just store it as an untyped
+              // non-enumerable property on the snapshot
+              let jsonBuf = (snapshotContent as any)[JSON_BUF_PROPERTY] || '';
+              jsonBuf += event.delta.partial_json;
+
+              Object.defineProperty(snapshotContent, JSON_BUF_PROPERTY, {
+                value: jsonBuf,
+                enumerable: false,
+                writable: true,
+              });
+
+              if (jsonBuf) {
+                snapshotContent.input = partialParse(jsonBuf);
+              }
+            }
+            break;
+          }
+          default:
+            checkNever(event.delta);
         }
+
         return snapshot;
       }
       case 'content_block_stop':
@@ -597,3 +634,6 @@ export class MessageStream implements AsyncIterable<MessageStreamEvent> {
     return stream.toReadableStream();
   }
 }
+
+// used to ensure exhaustive case matching without throwing a runtime error
+function checkNever(x: never) {}