diff --git a/js/plugins/anthropic/src/runner/beta.ts b/js/plugins/anthropic/src/runner/beta.ts
index 4efcd1fd13..24fcac60d8 100644
--- a/js/plugins/anthropic/src/runner/beta.ts
+++ b/js/plugins/anthropic/src/runner/beta.ts
@@ -51,7 +51,6 @@ import {
   unsupportedServerToolError,
 } from './converters/beta.js';
 import {
-  inputJsonDeltaError,
   redactedThinkingBlockToPart,
   textBlockToPart,
   textDeltaToPart,
@@ -464,7 +463,7 @@ export class BetaRunner extends BaseRunner<BetaRunnerTypes> {
         return thinkingDeltaToPart(event.delta);
       }
       if (event.delta.type === 'input_json_delta') {
-        throw inputJsonDeltaError();
+        return { data: event.delta.partial_json };
       }
       // signature_delta - ignore
       return undefined;
diff --git a/js/plugins/anthropic/src/runner/converters/shared.ts b/js/plugins/anthropic/src/runner/converters/shared.ts
index 6d6faf6091..ddb2fc0772 100644
--- a/js/plugins/anthropic/src/runner/converters/shared.ts
+++ b/js/plugins/anthropic/src/runner/converters/shared.ts
@@ -102,12 +102,3 @@ export function textDeltaToPart(delta: { text: string }): Part {
 export function thinkingDeltaToPart(delta: { thinking: string }): Part {
   return { reasoning: delta.thinking };
 }
-
-/**
- * Error for unsupported input_json_delta in streaming.
- */
-export function inputJsonDeltaError(): Error {
-  return new Error(
-    'Anthropic streaming tool input (input_json_delta) is not yet supported. Please disable streaming or upgrade this plugin.'
-  );
-}
diff --git a/js/plugins/anthropic/src/runner/stable.ts b/js/plugins/anthropic/src/runner/stable.ts
index 61c921b97c..e08031e85e 100644
--- a/js/plugins/anthropic/src/runner/stable.ts
+++ b/js/plugins/anthropic/src/runner/stable.ts
@@ -45,7 +45,6 @@ import { AnthropicConfigSchema, type ClaudeRunnerParams } from '../types.js';
 import { removeUndefinedProperties } from '../utils.js';
 import { BaseRunner } from './base.js';
 import {
-  inputJsonDeltaError,
   redactedThinkingBlockToPart,
   textBlockToPart,
   textDeltaToPart,
@@ -356,7 +355,7 @@ export class Runner extends BaseRunner<RunnerTypes> {
       }
 
       if (delta.type === 'input_json_delta') {
-        throw inputJsonDeltaError();
+        return { data: delta.partial_json };
       }
 
       // signature_delta - ignore
diff --git a/js/plugins/anthropic/tests/stable_runner_test.ts b/js/plugins/anthropic/tests/stable_runner_test.ts
index 28e1834e2a..478a9c1015 100644
--- a/js/plugins/anthropic/tests/stable_runner_test.ts
+++ b/js/plugins/anthropic/tests/stable_runner_test.ts
@@ -762,19 +762,18 @@ describe('fromAnthropicContentBlockChunk', () => {
     });
   }
 
-  it('should throw for unsupported tool input streaming deltas', () => {
-    assert.throws(
-      () =>
-        testRunner.fromAnthropicContentBlockChunk({
-          index: 0,
-          type: 'content_block_delta',
-          delta: {
-            type: 'input_json_delta',
-            partial_json: '{"foo":',
-          },
-        } as MessageStreamEvent),
-      /Anthropic streaming tool input \(input_json_delta\) is not yet supported/
-    );
+  it('should handle tool input streaming deltas', () => {
+    const actualOutput = testRunner.fromAnthropicContentBlockChunk({
+      index: 0,
+      type: 'content_block_delta',
+      delta: {
+        type: 'input_json_delta',
+        partial_json: '{"foo":',
+      },
+    } as MessageStreamEvent);
+    assert.deepStrictEqual(actualOutput, {
+      data: '{"foo":',
+    });
   });
 });
 
diff --git a/js/testapps/anthropic/README.md b/js/testapps/anthropic/README.md
index b209958e68..82f9182b69 100644
--- a/js/testapps/anthropic/README.md
+++ b/js/testapps/anthropic/README.md
@@ -72,4 +72,8 @@ Each source file defines flows that can be invoked from the Dev UI or the Genkit
 - `stable-vision-base64` – Analyze an image from a local file (base64 encoded)
 - `stable-vision-conversation` – Multi-turn conversation about an image
 
+### Tools
+- `anthropic-stable-tools` – Get the weather in a given location using a Genkit tool
+- `anthropic-stable-tools-stream` – Streaming response with Genkit tools
+
 Example: `genkit flow:run anthropic-stable-hello`
diff --git a/js/testapps/anthropic/src/stable/tools.ts b/js/testapps/anthropic/src/stable/tools.ts
index 95c62c5870..6947971600 100644
--- a/js/testapps/anthropic/src/stable/tools.ts
+++ b/js/testapps/anthropic/src/stable/tools.ts
@@ -54,3 +54,24 @@ ai.defineFlow(
     return text;
   }
 );
+
+ai.defineFlow(
+  'anthropic-stable-tools-stream',
+  async ({ place }: { place: string }, { sendChunk }) => {
+    const { stream } = ai.generateStream({
+      model: anthropic.model('claude-sonnet-4-5'),
+      tools: [getWeather],
+      prompt: `What is the weather in ${place}?`,
+    });
+
+    let response = '';
+    for await (const chunk of stream) {
+      response += chunk.text ?? '';
+      if (chunk.text) {
+        sendChunk(chunk.text);
+      }
+    }
+
+    return response;
+  }
+);