@factory/droid-sdk

TypeScript SDK for the Factory Droid CLI. Provides a high-level API for interacting with Droid as a subprocess, with streaming message support, multi-turn sessions, spec mode, tool controls, initialization metadata, session forking, session discovery, and tool permission handling.

Requirements

• Node.js 18+
• The droid CLI installed and available on your PATH

Installation

npm install @factory/droid-sdk

Quick Start

Send a one-shot prompt and stream the response:

import { DroidMessageType, query } from '@factory/droid-sdk';

const stream = query({
  prompt: 'What files are in the current directory?',
  cwd: '/my/project',
});

for await (const msg of stream) {
  if (msg.type === DroidMessageType.AssistantTextDelta) {
    process.stdout.write(msg.text);
  }
  if (msg.type === DroidMessageType.TurnComplete) {
    console.log('\nDone!');
  }
}

Multi-Turn Sessions

Use createSession() for persistent conversations with multiple turns:

import { createSession, DroidMessageType } from '@factory/droid-sdk';

const session = await createSession({ cwd: '/my/project' });

// Streaming turn
for await (const msg of session.stream('List all TypeScript files')) {
  if (msg.type === DroidMessageType.AssistantTextDelta) {
    process.stdout.write(msg.text);
  }
}

// Non-streaming turn
const result = await session.send('Summarize the project');
console.log(result.text);

await session.close();

Resume an existing session by ID:

import { resumeSession } from '@factory/droid-sdk';

const session = await resumeSession('session-id-here');
const result = await session.send('Continue where we left off');
console.log(result.text);
await session.close();

The returned DroidSession also exposes session.initResult, which contains the raw initialize_session or load_session result returned by the JSON-RPC server.

Initialization Metadata

Inspect the raw initialization metadata from query(), createSession(), and resumeSession():

import { createSession, query, resumeSession } from '@factory/droid-sdk';

const stream = query({
  prompt: 'Reply with "ready" and nothing else.',
  cwd: '/my/project',
});

console.log(stream.sessionId); // null before initialization
console.log(stream.initResult); // null before initialization

const initialized = await stream.initialized;
console.log(initialized.sessionId);
console.log(initialized.settings.modelId);
stream.abort();

const session = await createSession({ cwd: '/my/project' });
console.log(session.initResult.settings.modelId);

const resumed = await resumeSession(session.sessionId, { cwd: '/my/project' });
console.log(resumed.initResult.cwd);

await resumed.close();
await session.close();

Spec Mode

Start a session directly in spec mode, or enter spec mode later on an existing session:

import {
  createSession,
  DroidInteractionMode,
  ReasoningEffort,
} from '@factory/droid-sdk';

const session = await createSession({
  cwd: '/my/project',
  interactionMode: DroidInteractionMode.Spec,
  specModeReasoningEffort: ReasoningEffort.High,
  specModeModelId: 'claude-sonnet-4-20250514',
});

const plan = await session.send('Draft a plan for adding integration tests');
console.log(plan.text);

await session.enterSpecMode({
  specModeReasoningEffort: ReasoningEffort.High,
});

await session.close();

When handling spec-mode approval, you can approve implementation in the same session with ToolConfirmationOutcome.ProceedOnce, or hand off to a fresh session with ToolConfirmationOutcome.ProceedNewSessionHigh.

Tool Controls

Control which exec tools are available at session start, inspect the current tool catalog, and update tool overrides later:

import { createSession } from '@factory/droid-sdk';

const session = await createSession({
  cwd: '/my/project',
  enabledToolIds: ['Read'],
  disabledToolIds: ['Execute'],
});

const { tools } = await session.listTools();
console.log(
  tools.map((tool) => ({
    id: tool.llmId,
    allowed: tool.currentlyAllowed,
  }))
);

await session.updateSettings({
  disabledToolIds: ['Read', 'Execute'],
});

await session.close();

Forking Sessions

Fork the current server-side session and continue from the new session ID:

import { createSession, resumeSession } from '@factory/droid-sdk';

const session = await createSession({ cwd: '/my/project' });

await session.send('Remember this phrase: mango sunrise');

const { newSessionId } = await session.forkSession();
const fork = await resumeSession(newSessionId, { cwd: '/my/project' });

const result = await fork.send('What phrase did I ask you to remember?');
console.log(result.text);

await fork.close();
await session.close();

Listing Sessions

Discover droid sessions saved on disk (mirrors the CLI's /sessions command). Reads ~/.factory/sessions/ directly — no droid process is spawned, so this works even when no session is running:

import { listSessions } from '@factory/droid-sdk';

// Sessions for the current project (cwd defaults to process.cwd())
const current = await listSessions();

// 10 most recent sessions in the current project
const recent = await listSessions({ numSessions: 10 });

// Every session on disk, most recent first
const all = await listSessions({ fetchOutsideCWD: true });

// 10 most recent sessions across all projects
const recentAcrossProjects = await listSessions({
  fetchOutsideCWD: true,
  numSessions: 10,
});

// Sessions for a specific other project
const other = await listSessions({ cwd: '/Users/me/other-repo' });

for (const s of current) {
  console.log(`[${s.id}] ${s.title} (${s.messageCount} msgs)`);
}

Each SessionMetadata record includes id, title, sessionTitle, owner, messageCount, modifiedTime, createdTime, isFavorite, cwd, decompSessionType, and decompMissionId. Archived sessions (those with an archivedAt in their settings file) are excluded automatically. Results are sorted by modifiedTime descending.

ListSessionsOptions:

• cwd — working directory to scope the listing to (default process.cwd()). Ignored when fetchOutsideCWD is true.
• fetchOutsideCWD — return sessions from every working directory on disk (default false)
• numSessions — cap on total sessions returned
• sessionsDir — override the sessions root (default ~/.factory/sessions/)

Permission Handling

Handle tool confirmation requests with a custom permission handler:

import {
  DroidMessageType,
  query,
  ToolConfirmationOutcome,
} from '@factory/droid-sdk';

const stream = query({
  prompt: 'Create a hello.txt file',
  cwd: '/my/project',
  permissionHandler(params) {
    console.log('Tool permission requested:', params);
    return ToolConfirmationOutcome.ProceedOnce;
  },
});

for await (const msg of stream) {
  if (msg.type === DroidMessageType.AssistantTextDelta) {
    process.stdout.write(msg.text);
  }
}

API Reference

Top-Level Functions

| Function | Description | | ----------------------------- | ---------------------------------------------------------------- | | query(options) | One-shot prompt → async generator of DroidMessage events | | createSession(options?) | Create a new multi-turn session → DroidSession | | resumeSession(id, options?) | Resume an existing session → DroidSession | | listSessions(options?) | List droid sessions saved on disk → Promise<SessionMetadata[]> |

query(options): DroidQuery

Returns an async generator that yields DroidMessage events. The returned DroidQuery object also exposes:

• interrupt() — gracefully interrupt the agent's current turn
• abort() — forcefully kill the subprocess
• sessionId — the session ID (available after initialization)
• initResult — cached initialize_session result, or null before initialization
• initialized — promise that resolves with the initialize_session result

query(options) also accepts an abortSignal for external cancellation.

DroidSession

Returned by createSession() and resumeSession(). Key methods:

• stream(text, options?) — send a message, returns async generator of DroidMessage
• send(text, options?) — send a message, returns aggregated DroidResult
• interrupt() — interrupt the current turn
• close() — close the session and release resources
• updateSettings(params) — update model, autonomy level, etc.
• enterSpecMode(params?) — switch the current session into spec mode
• forkSession() — create a forked server-side session and return its new session ID
• addMcpServer(params) / removeMcpServer(params) / toggleMcpServer(params) — manage MCP servers
• listMcpServers() / listMcpTools() / authenticateMcpServer(params) — inspect and authenticate MCP servers
• listTools(params?) — inspect the exec tool catalog and current allow/deny state
• renameSession(params) — rename the current session
• sessionId — the session ID
• initResult — cached initialize_session or load_session result

DroidResult

Returned by session.send():

• text — concatenated assistant response text
• messages — all DroidMessage objects from the turn
• tokenUsage — final token usage, or null

DroidMessage Types

All messages have a discriminated type field:

import { DroidMessageType } from '@factory/droid-sdk';

if (msg.type === DroidMessageType.AssistantTextDelta) {
  process.stdout.write(msg.text);
}

| Type | Description | | ----------------------- | --------------------------------------- | | assistant_text_delta | Streaming text token from the assistant | | thinking_text_delta | Streaming reasoning/thinking token | | tool_use | Tool invocation by the assistant | | tool_result | Result from a tool execution | | tool_progress | Progress update during tool execution | | working_state_changed | Agent working state transition | | token_usage_update | Updated token usage counters | | create_message | Full assistant message created | | turn_complete | Sentinel: agent turn finished | | session_title_updated | Session title changed | | mcp_status_changed | MCP server status changed | | mcp_auth_required | MCP authentication required | | mcp_auth_completed | MCP authentication completed | | error | Error event from the process |

Options

QueryOptions and CreateSessionOptions accept:

• prompt — the user prompt (query only)
• cwd — working directory for the session
• modelId — LLM model identifier
• autonomyLevel — AutonomyLevel enum value
• interactionMode — DroidInteractionMode enum value
• reasoningEffort — ReasoningEffort enum value
• specModeModelId — override model used in spec mode
• specModeReasoningEffort — override reasoning level used in spec mode
• mcpServers — initial MCP server configurations, including SDK-backed MCP servers from createSdkMcpServer()
• enabledToolIds — explicit exec tool allowlist
• disabledToolIds — explicit exec tool denylist
• permissionHandler — callback for tool confirmations
• askUserHandler — callback for interactive questions
• abortSignal — standard AbortSignal for cancellation
• execPath — path to droid executable (default: "droid")
• transport — provide a custom transport instead of spawning a process

DroidClient

Low-level JSON-RPC client for advanced use. Provides typed methods for the underlying protocol operations, including listTools() and renameSession(). Most users should prefer query() and createSession().

Error Types

| Error | Description | | ---------------------- | -------------------------------------- | | ConnectionError | Failed to connect to the droid process | | ProtocolError | JSON-RPC protocol error | | SessionError | Base session error | | SessionNotFoundError | Session ID not found | | TimeoutError | Request timed out | | ProcessExitError | Droid subprocess exited unexpectedly |

Examples

See the examples/ directory for runnable examples:

• simple-query.ts — one-shot query with streaming output
• multi-turn-session.ts — multi-turn session lifecycle
• abort-session-stream.ts — cancel an in-flight streaming session turn with AbortSignal
• init-metadata.ts — read initialization and load metadata from query/session APIs
• permission-handler.ts — custom permission handling
• spec-mode-same-session.ts — approve a spec and continue in the same session
• spec-mode-new-session.ts — approve a spec and hand off implementation to a new session
• tool-controls.ts — configure allow/deny lists and inspect tool availability
• sdk-mcp-tool.ts — expose SDK-defined tools to Droid through MCP
• fork-session.ts — fork a session and continue from the new session ID
• list-sessions.ts — discover droid sessions saved on disk

License

Apache 2.0