Jules Mcp

An SDK for running a fleet of coding agents in the Cloud

Orchestrate complex, long-running coding tasks to an ephemeral cloud environment integrated with a GitHub repo.

Send work to a Cloud based session

import { jules } from '@google/jules-sdk';

const session = await jules.session({
  prompt: `Fix visibility issues in the examples/nextjs app.

  **Visibility issues**
  - White text on white backgrounds
  - Low contrast on button hover

  **Instructions**
  - Update the global styles and page components to a dark theme with the shadcn zinc palette.
`,
  source: { github: 'davideast/dataprompt', baseBranch: 'main' },
  autoPr: true,
});

Monitor agent progress

import { jules } from '@google/jules-sdk';

const session = jules.session('<session-id>');

for await (const activity of session.stream()) {
  switch (activity.type) {
    case 'planGenerated':
      console.log(`${activity.plan.steps.length} steps.`);
      break;
    case 'progressUpdated':
      console.log(`${activity.title}`);
      // Check for code updates
      for (const artifact of activity.artifacts) {
        if (artifact.type === 'changeSet') {
          const parsed = artifact.parsed();
          for (const file of parsed.files) {
            console.log(`${file.path}: +${file.additions} -${file.deletions}`);
          }
        }
      }
      break;
    case 'sessionCompleted':
      console.log('Session finished successfully.');
      break;
  }
}

// Get the pull-request URL once complete
const outcome = await session.result();
if (outcome.pullRequest) {
  console.log(`PR: ${outcome.pullRequest.url}`);
}

Installation

npm i @google/jules-sdk
export JULES_API_KEY=<api-key>

Core Features

Run Cloud Functions with a Coding Agent

Jules sessions run in the cloud and can run without a GitHub repository. We call these "Repoless" sessions. They are incredibly powerful because they act like preconfigured serverless functions. The Jules VM comes with a preconfigured image with Node.js, Python, Rust, Bun, and many other runtimes and tools.

Pass context through the prompt and have the agent generate the result.

import { jules } from '@google/jules-sdk';
import { sql } from 'drizzle-orm';

const longDocumentsNobodyWantsToRead = await sql`SELECT * FROM documents`;
const userPrompt = process.argv[2];

const session = await jules.session({
  prompt: `You are a assistant that can read long documents and answer questions about them.

  ## The user's question
  ${userPrompt}

  ## The documents
  ${longDocumentsNobodyWantsToRead.map((e) => e.title).join('\n')}
  
  ## Answer Format
  Create a markdown response with the following sections:
  - Summary
  - Answer
  - Sources Cited
  `,
});

const result = await session.result();
const files = result.generatedFiles();
const answer = files.get('answer.md');
console.log(answer?.content);

// Call the script as CLI
// node index.js "Review the policies and explain to me delivery timelines like I'm 7 years old."

Interactive Sessions

Use jules.session() for workflows where you observe, provide feedback, and guide the process.

const session = await jules.session({
  prompt: 'Refactor the user authentication module.',
  source: { github: 'your-org/your-repo', baseBranch: 'develop' },
});

console.log(`Session created: ${session.id}`);

await session.waitFor('awaitingPlanApproval');
console.log('Plan is ready. Approving it now.');
await session.approve();

const reply = await session.ask(
  'Start with the first step and let me know when it is done.',
);
console.log(`[AGENT] ${reply.message}`);

const outcome = await session.result();
console.log(`Session finished with state: ${outcome.state}`);

Create a fleet of agent sessions

Process multiple items in parallel with jules.all(). Feels like Promise.all() but with built-in concurrency control.

const todos = ['Fix login bug', 'Update README', 'Refactor tests'];

const sessions = await jules.all(todos, (task) => ({
  prompt: task,
  source: { github: 'user/repo', baseBranch: 'main' },
}));

console.log(`Created ${sessions.length} sessions.`);

For more control over the concurrency count and error handling.

const sessions = await jules.all(largeList, mapFn, {
  concurrency: 10,
  stopOnError: false,
  delayMs: 500,
});

Query your local knowledge base

The SDK caches session data locally and exposes a query language for filtering and projecting across all sessions.

// Find failed sessions
const failures = await jules.select({
  from: 'sessions',
  where: { state: 'failed' },
  limit: 10,
});

// Get recent agent messages with computed summaries
const messages = await jules.select({
  from: 'activities',
  where: { type: 'agentMessaged' },
  select: ['id', 'createTime', 'summary', 'artifactCount'],
  order: 'desc',
  limit: 5,
});

// Find activities with bash errors (exitCode > 0)
const errors = await jules.select({
  from: 'activities',
  where: { 'artifacts.exitCode': { $gt: 0 } },
});

Reactive Streams

The .stream() method returns an AsyncIterator to observe the agent's progress.

for await (const activity of session.stream()) {
  switch (activity.type) {
    case 'planGenerated':
      console.log(
        'Plan:',
        activity.plan.steps.map((s) => s.title),
      );
      break;
    case 'agentMessaged':
      console.log('Agent says:', activity.message);
      break;
    case 'sessionCompleted':
      console.log('Session complete!');
      break;
  }
}

Code Diffs, Shell Output, and Media Artifacts

Activities can contain artifacts: code changes (changeSet), shell output (bashOutput), or images (media).

for (const artifact of activity.artifacts) {
  if (artifact.type === 'bashOutput') {
    console.log(artifact.toString());
  }
  if (artifact.type === 'changeSet') {
    const parsed = artifact.parsed();
    for (const file of parsed.files) {
      console.log(`${file.path}: +${file.additions} -${file.deletions}`);
    }
  }
  if (artifact.type === 'media' && artifact.format === 'image/png') {
    await artifact.save(`./screenshots/${activity.id}.png`);
  }
}

SDK Configuration

The default jules instance looks for the environment variable JULES_API_KEY. If you need to set an API key in code or create multiple instances, use the with method.

import { jules } from '@google/jules-sdk';

// Multiple API keys
const customJules = jules.with({ apiKey: 'other-api-key' });

// Polling & timeouts
const customJules = jules.with({
  pollingIntervalMs: 2000,
  timeout: 60000,
});

Error Handling

The SDK provides multiple error types that inherit from JulesError.

import {
  jules,
  JulesError,
  JulesNetworkError,
  JulesApiError,
  JulesRateLimitError,
  MissingApiKeyError
} from '@google/jules-sdk';

try {
  const session = await jules.session({ ... });
} catch (error) {
  if (error instanceof JulesError) {
    console.error(`SDK error: ${error.message}`);
  }
}

Agent Sources

Each agent session has a source property that defines what the source context is used for the session. This is primarily a GitHub repository, but sessions can also run without a source and use only the context passed in the prompt.

// List all connected sources
for await (const source of jules.sources()) {
  if (source.type === 'githubRepo') {
    console.log(`${source.githubRepo.owner}/${source.githubRepo.repo}`);
    console.log(`  Private: ${source.githubRepo.isPrivate}`);
  }
}

// Get a specific source
const myRepo = await jules.sources.get({ github: 'my-org/my-project' });
if (myRepo) {
  console.log(`Found: ${myRepo.id}`);
}

API Overview

• Core:
  • jules: The pre-initialized client.
  • jules.with(options): Creates a new client with custom configuration.
  • jules.run(options): Creates an automated session.
  • jules.session(options): Creates or rehydrates an interactive session.
  • jules.all(items, mapFn, options): Batch processing.
• Session Control:
  • session.ask(): Sends a message and awaits the agent's reply.
  • session.send(): Sends a fire-and-forget message.
  • session.approve(): Approves a pending plan.
  • session.waitFor(): Pauses until the session reaches a specific state.
  • session.result(): Awaits the final outcome.
• Observation:
  • session.stream(): Async iterator of all activities.
  • session.history(): Stream of cached activities.
  • session.updates(): Stream of live activities.
  • session.select(query): Query local cache.
  • session.info(): Fetch latest session state.
• Artifacts:
  • artifact.save(): Save to filesystem.
  • artifact.toUrl(): Get data URI.
  • artifact.toString(): Formatted output for bash artifacts.
  • artifact.parsed(): Structured diff parsing for changesets.
• Sources:
  • jules.sources(): Async iterator over all connected sources.
  • jules.sources.get(filter): Retrieve a specific source by identifier.

License

Apache-2.0

Note: This is not an officially supported Google product. This project is not eligible for the Google Open Source Software Vulnerability Rewards Program.