feat(sdk): Implement dynamic system instructions (#18863)

Co-authored-by: N. Taylor Mullen <ntaylormullen@google.com>
2026-04-24 03:54:43 -07:00 · 2026-02-13 12:48:35 -08:00
parent f460ab841d
commit f76e24c00f
6 changed files with 258 additions and 7 deletions
@@ -0,0 +1,154 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+import { GeminiCliAgent } from './agent.js';
+import * as path from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { dirname } from 'node:path';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+// Set this to true locally when you need to update snapshots
+const RECORD_MODE = process.env['RECORD_NEW_RESPONSES'] === 'true';
+
+const getGoldenPath = (name: string) =>
+  path.resolve(__dirname, '../test-data', `${name}.json`);
+
+describe('GeminiCliAgent Integration', () => {
+  it('handles static instructions', async () => {
+    const goldenFile = getGoldenPath('agent-static-instructions');
+
+    const agent = new GeminiCliAgent({
+      instructions: 'You are a pirate. Respond in pirate speak.',
+      model: 'gemini-2.0-flash',
+      recordResponses: RECORD_MODE ? goldenFile : undefined,
+      fakeResponses: RECORD_MODE ? undefined : goldenFile,
+    });
+
+    const events = [];
+    const stream = agent.sendStream('Say hello.');
+
+    for await (const event of stream) {
+      events.push(event);
+    }
+
+    const textEvents = events.filter((e) => e.type === 'content');
+    const responseText = textEvents
+      .map((e) => (typeof e.value === 'string' ? e.value : ''))
+      .join('');
+
+    // Expect pirate speak
+    expect(responseText.toLowerCase()).toMatch(/ahoy|matey|arrr/);
+  }, 30000);
+
+  it('handles dynamic instructions', async () => {
+    const goldenFile = getGoldenPath('agent-dynamic-instructions');
+
+    let callCount = 0;
+    const agent = new GeminiCliAgent({
+      instructions: (_ctx) => {
+        callCount++;
+        return `You are a helpful assistant. The secret number is ${callCount}. Always mention the secret number when asked.`;
+      },
+      model: 'gemini-2.0-flash',
+      recordResponses: RECORD_MODE ? goldenFile : undefined,
+      fakeResponses: RECORD_MODE ? undefined : goldenFile,
+    });
+
+    // First turn
+    const stream1 = agent.sendStream('What is the secret number?');
+    const events1 = [];
+    for await (const event of stream1) {
+      events1.push(event);
+    }
+    const responseText1 = events1
+      .filter((e) => e.type === 'content')
+      .map((e) => (typeof e.value === 'string' ? e.value : ''))
+      .join('');
+
+    expect(responseText1).toContain('1');
+    expect(callCount).toBe(1);
+
+    // Second turn
+    const stream2 = agent.sendStream('What is the secret number now?');
+    const events2 = [];
+    for await (const event of stream2) {
+      events2.push(event);
+    }
+    const responseText2 = events2
+      .filter((e) => e.type === 'content')
+      .map((e) => (typeof e.value === 'string' ? e.value : ''))
+      .join('');
+
+    // Should still be 1 because instructions are only loaded once per session
+    expect(responseText2).toContain('1');
+    expect(callCount).toBe(1);
+  }, 30000);
+
+  it('handles async dynamic instructions', async () => {
+    const goldenFile = getGoldenPath('agent-async-instructions');
+
+    let callCount = 0;
+    const agent = new GeminiCliAgent({
+      instructions: async (_ctx) => {
+        await new Promise((resolve) => setTimeout(resolve, 10)); // Simulate async work
+        callCount++;
+        return `You are a helpful assistant. The secret number is ${callCount}. Always mention the secret number when asked.`;
+      },
+      model: 'gemini-2.0-flash',
+      recordResponses: RECORD_MODE ? goldenFile : undefined,
+      fakeResponses: RECORD_MODE ? undefined : goldenFile,
+    });
+
+    // First turn
+    const stream1 = agent.sendStream('What is the secret number?');
+    const events1 = [];
+    for await (const event of stream1) {
+      events1.push(event);
+    }
+    const responseText1 = events1
+      .filter((e) => e.type === 'content')
+      .map((e) => (typeof e.value === 'string' ? e.value : ''))
+      .join('');
+
+    expect(responseText1).toContain('1');
+    expect(callCount).toBe(1);
+
+    // Second turn
+    const stream2 = agent.sendStream('What is the secret number now?');
+    const events2 = [];
+    for await (const event of stream2) {
+      events2.push(event);
+    }
+    const responseText2 = events2
+      .filter((e) => e.type === 'content')
+      .map((e) => (typeof e.value === 'string' ? e.value : ''))
+      .join('');
+
+    // Should still be 1 because instructions are only loaded once per session
+    expect(responseText2).toContain('1');
+    expect(callCount).toBe(1);
+  }, 30000);
+
+  it('throws when dynamic instructions fail', async () => {
+    const agent = new GeminiCliAgent({
+      instructions: () => {
+        throw new Error('Dynamic instruction failure');
+      },
+      model: 'gemini-2.0-flash',
+    });
+
+    const stream = agent.sendStream('Say hello.');
+
+    await expect(async () => {
+      for await (const _event of stream) {
+        // Just consume the stream
+      }
+    }).rejects.toThrow('Dynamic instruction failure');
+  });
+});