Claude Managed Agents is a suite of composable APIs from 📝Anthropic for building, running, and observing cloud-hosted AI agents at scale, launched in public beta on April 8, 2026. The platform decouples the model — the "brain" — from execution infrastructure — the "hands" — by providing a fully managed, sandboxed environment in which 📝Claude can read files, run commands, browse the web, and execute code under scoped credentials.

Key Facts

Status: Public beta (requires managed-agents-2026-04-01 beta header; SDK sets it automatically)
Access: Enabled by default for all API accounts
Pricing: Standard token pricing + $0.08/session-hour (runtime only, measured to the millisecond) + $10/1k web searches
CLI: ant CLI available via Homebrew (macOS), curl (Linux), or Go install
SDKs: Python, TypeScript, Java, Go, C#, Ruby, PHP
Rate limits: 60 RPM for create endpoints, 600 RPM for read endpoints (org-level)
Batch API discounts do not apply — Managed Agents is billed separately from the standard Messages API
Research preview features: Outcomes, multiagent, and memory (require access request)

Core Concepts

The platform is built around four primitives:

How It Works

Create an agent — define model (e.g., claude-opus-4-7), system prompt, and tools
Create an environment — configure a cloud container with networking rules
Start a session — launch a session referencing your agent and environment
Send events and stream responses — send user messages as events; Claude autonomously executes tools and streams results via SSE
Steer or interrupt — send additional events to guide the agent mid-execution, or interrupt to change direction

When a session starts, the agent loop runs autonomously: Claude decides which tools to use, executes them inside the sandboxed container, and streams events back. The session emits session.status_idle when complete. Sessions persist file systems and conversation history across multiple interactions.

Built-in Tools

The agent_toolset_20260401 tool type enables all built-in tools:

Tools can be individually enabled/disabled via a configs array. Custom tools (client-executed, like Messages API tool use) are also supported alongside the built-in toolset.

Architecture: Brain-Hands Decoupling

The engineering design follows an operating systems principle: virtualizing components into stable abstractions that outlast implementations.

Session — a durable, append-only event log stored outside Claude's context window. Supports crash recovery via wake(sessionId). The session functions as "a context object that lives outside the context window."

Harness — stateless and decoupled. No longer assumes resources exist in its container. Provisions containers only when Claude requests them via tool calls. Can be rebooted independently without losing session data. Reduced time-to-first-token by ~60% at p50 and >90% at p95.

Sandbox — containers became replaceable "cattle" rather than precious "pets." Each execution environment is a tool with a uniform interface: execute(name, input) → string.

Credential isolation — tokens never become reachable from sandboxes executing Claude-generated code. Two patterns enforce this: resource-bundled auth (tokens used at sandbox init, then discarded) and vault-based OAuth (MCP with tokens stored outside the sandbox).

Scaling — the decoupled design enables multiple stateless harnesses serving the same session, and multiple sandboxes serving the same harness. Customers can run harnesses in their own VPCs without network peering.

Messages API vs Managed Agents

Positioned Alongside

📝Claude Cowork — Anthropic's enterprise collaboration product
📝Claude Code — Terminal-native agent (local execution; Managed Agents is cloud execution)
📝Agent SDK — Lower-level SDK for building custom agent loops

Early adopters include Notion, Rakuten, and Asana.