# Overview

# What is Standard Agents Builder?

Standard agents are portable agents that follow the [Standard Agent Specification](https://standardagentspec.org). The specification is at version 0.2.0. Standard Agents Builder is a first-party tool for building, deploying, and managing standard agents.

Standard agents support specific tasks, workflows, or business use cases. You choose the models and tools for each agent. Side-owned subagent relationships compose agents into larger systems.

Standard Agents Builder uses a Vite plugin to configure your runtime. It includes a built-in admin UI for testing and monitoring agents. A CLI scaffolds and manages projects. SDKs connect your applications to thread APIs. Production deployment uses Standard Agents hosting.

## Key Features

### Persistent Conversation Threads

Every agent thread is backed by a Cloudflare Durable Object with its own isolated SQLite database. This means:

- Message history is automatically persisted
- Execution logs and tool calls are tracked on a per-thread basis
- Conversation state is maintained across requests
- Each thread is fully isolated

### Composable Subagents

Agents can run as child threads through side-owned relationships.

- Parent and child communicate through durable queued messages
- Child results/failures are returned with attachment-safe path copying
- A prompt-backed owning side receives lifecycle tools (`subagents`, `subagent_create`, `subagent_message`)
- Child instances can be named and tracked in parent registry state

### Built-in Admin UI

Standard Agents includes a complete admin interface for:

- Testing agents in real time
- Monitoring conversation threads
- Viewing execution logs and debugging

### File-Based Auto-Discovery

All agents, prompts, models, and tools are defined as type-safe TypeScript files.

- Definition files in the recognized `agents/` subdirectories are discovered and loaded
- Agents, prompts, models, tools, and hooks are all committed to source control.
- You change an agent by editing its TypeScript file.
- Type-safe with TypeScript autocomplete for the defined tools, prompts, models, and agents.

## Next Steps

- [Installation](/docs/introduction/installation)

  Get Standard Agents up and running in minutes

* [Architecture](/docs/introduction/architecture)

  Understand how Standard Agents work

- [API reference](/docs/api-reference/rest/create-thread)

  Read the thread and message API