Gemini CLI SDK for Dart

A powerful Dart SDK for interacting with Google Gemini CLI, providing seamless integration with AI-powered coding assistance through the Gemini CLI tool.

Features

  • πŸš€ Shared Core: Built on top of programming_cli_core_sdk for consistent streaming, schema, and file workflows across Codex, Claude, and Gemini.
  • πŸ“ File Support: Attach local files or in-memory bytes through the shared PromptContent helpers.
  • πŸ“‹ Schema Orchestration: Generate structured responses that are automatically validated against JSON schemas.
  • πŸ”Œ MCP Management: Inspect and configure Model Context Protocol servers using the shared MCP models.
  • 🌊 Streaming: Stream Gemini responses while the core handles cleanup and schema validation.
  • πŸ› οΈ CLI Utilities: Check, install, and upgrade the Gemini CLI with convenience helpers.
  • πŸ” Secure: Isolated environment per API key prevents credential leakage.

Prerequisites

  1. Node.js and npm (for Gemini CLI)

  2. Gemini CLI

    • Install globally: npm install -g @google/gemini-cli
    • Or use the SDK's installGeminiCLI() helper

  3. Gemini API Key (Optional)

    • Create one in Google AI Studio
    • Or sign in to Gemini CLI with: gemini login
    • Or export it as GEMINI_API_KEY environment variable

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  gemini_cli_sdk: ^3.0.0

Then run dart pub get.

Architecture Overview

As of v3.0.0 the Gemini SDK is a thin implementation on top of programming_cli_core_sdk. The core package provides:

  • PromptContent for text, file, bytes, and JSON prompts
  • Process orchestration, streaming, and schema validation
  • Shared MCP models and CLI helpers

GeminiChat is responsible only for constructing the Gemini CLI command and interpreting its output. This keeps the behaviour aligned with the Codex and Claude SDKs.

Quick Start

Authentication Options

The SDK supports three authentication methods:

Option 1: Use CLI Login (Recommended for Development)

import 'package:gemini_cli_sdk/gemini_cli_sdk.dart';

Future<void> main() async {
  // No API key needed - uses existing CLI authentication
  final gemini = Gemini();

  final chat = gemini.createNewChat();
  // ... use the chat
}

Option 2: Provide API Key to SDK

import 'package:gemini_cli_sdk/gemini_cli_sdk.dart';

Future<void> main() async {
  // API key applies to all chats from this SDK instance
  final gemini = Gemini(apiKey: 'YOUR_API_KEY');

  final chat = gemini.createNewChat();
  // ... use the chat
}

Option 3: Provide API Key Per Chat

import 'package:gemini_cli_sdk/gemini_cli_sdk.dart';

Future<void> main() async {
  final gemini = Gemini(apiKey: 'DEFAULT_KEY');

  // This chat uses the SDK's default key
  final chat1 = gemini.createNewChat();

  // This chat overrides with a different key
  final chat2 = gemini.createNewChat(apiKey: 'SPECIAL_KEY');

  // ... use the chats
}

Basic Usage

import 'package:gemini_cli_sdk/gemini_cli_sdk.dart';

Future<void> main() async {
  // Initialize the SDK (API key is optional)
  final gemini = Gemini(apiKey: 'YOUR_API_KEY');
  final chat = gemini.createNewChat(
    options: const GeminiChatOptions(
      model: 'gemini-2.5-flash',
      allowedTools: ['*'],
      allowedMcpServerNames: ['playwright'],
    ),
  );

  try {
    final reply = await chat.sendMessage([
      PromptContent.text('What is the capital of France?'),
    ]);

    print('Gemini: $reply');
  } finally {
    await chat.dispose();
    await gemini.dispose();
  }
}

Sending Files

final response = await chat.sendMessage([
  PromptContent.text('Summarise the findings in this report'),
  PromptContent.file(File('report.md')),
]);

Structured Responses with JSON Schema

final schema = SchemaDefinition.object(
  properties: {
    'company': SchemaProperty.string(nullable: false),
    'revenue': SchemaProperty.number(nullable: false),
  },
);

final result = await chat.sendMessageWithSchema(
  messages: [
    PromptContent.text('Extract the company name and revenue from this article.'),
    PromptContent.file(File('article.html')),
  ],
  schema: schema,
);

print(result.llmMessage);
print(result.structuredSchemaData);

Streaming Responses

final stream = chat.streamResponse([
  PromptContent.text('Explain the Gemini CLI in bullet points'),
]);

await for (final chunk in stream) {
  stdout.write(chunk);
}

GeminiChatOptions

GeminiChatOptions controls how the CLI is invoked. Common fields include:

  • model: Gemini model identifier (gemini-2.5-flash, gemini-2.5-pro, etc.)
  • allowedTools: Explicit tool whitelist passed via --allowed-tools
  • allowedMcpServerNames: MCP servers Gemini may call (--allowed-mcp-server-names)
  • approvalMode: Tool approval strategy (--approval-mode)
  • repeatSystemPrompt: Reuse the system prompt on every turn
  • resumeSessionId: Resume a previous Gemini CLI session
  • additionalArgs: Extra CLI flags forwarded verbatim

All options extend CliChatOptions, so systemPrompt, model, and cwd are shared across SDKs.

MCP Helpers

final gemini = Gemini(apiKey: 'YOUR_API_KEY');

final mcpInfo = await gemini.isMcpInstalled();
print('MCP available: ${mcpInfo.hasMcpSupport}');

await gemini.installPopularMcpServer(
  'filesystem',
  environment: {'ROOT': '/Users/me/Projects'},
);

final servers = await gemini.listMcpServers();
for (final server in servers) {
  print('Configured MCP: ${server.name} -> ${server.command} ${server.args.join(' ')}');
}

CLI Management

final gemini = Gemini(apiKey: 'YOUR_API_KEY');

final installed = await gemini.isGeminiCLIInstalled();
if (!installed) {
  await gemini.installGeminiCLI();
}

await gemini.updateToNewestVersionIfNeeded();
final info = await gemini.getSDKInfo();
print(info);

Migration Notes (v3.0.0)

  • Use PromptContent instead of GeminiSdkContent.
  • Catch CliException instead of GeminiSDKException.
  • Import gemini_cli_sdk.dart to gain access to the shared core exports.
  • GeminiChatOptions now aligns with the options used by the Codex and Claude SDKs.

License

MIT

Libraries

gemini_cli_sdk