Claude Managed Agents is a beta managed harness. This comparison covers its Anthropic-managed cloud environment; its self-hosted execution option has a separate infrastructure boundary. Read the source ↗

Agent sandboxes / Claude Managed Agents alternative

Claude Managed Agents alternative for your own agent harness

Claude Managed Agents supplies an agent harness as well as execution infrastructure. Sandbox0 supplies the persistent Linux computer for a harness you run. Compare that product boundary first, then the lifetime of its files and the cost of execution.

Start buildingCompare capabilities ↓

Reviewed 2026-10-18 · Published by the Sandbox0 team

When Claude Managed Agents fits

Claude Managed Agents fits teams that want Anthropic to operate the agent loop, tools, conversation events, and cloud environment. Stateful sessions and asynchronous tasks are built into that managed harness.

When to consider Sandbox0

Consider Sandbox0 when you need to choose and operate the harness while retaining a per-user Linux RootFS across tasks. Its online storage growth and paused Files API target the execution environment; model calls and agent orchestration remain your application’s responsibility.

Capabilities

Claude Managed Agents and Sandbox0: what persists?

Feature comparison with documentation and verification status
Environment and runtime lifetimeClaude Managed AgentsManaged sessions support long-running asynchronous tasks and multiple interactions.View evidence ↗Sandbox0ttl and hard_ttl default to 0 (disabled). Configure idle pause and deletion policies for the same persistent sandbox identity; an idle running sandbox still accrues compute charges.Read documentation →
Persistent filesClaude Managed AgentsSession filesystem and outputs persist across interactions within that session.View evidence ↗Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFSClaude Managed AgentsEach new session receives a fresh cloud container. An environment ID does not share filesystem changes between sessions.View evidence ↗Sandbox0Persistence extends beyond /workspace to paths such as /usr/local, /etc, and /home. Runtime tmpfs and virtual filesystems are excluded.Read documentation →
Release compute, keep stateClaude Managed AgentsManaged sessions resume after pauses; this is a harness lifecycle, not a general VM checkpoint interface.View evidence ↗Sandbox0Pause compute between tasks; resume on available capacity. Default resume starts fresh processes from the saved filesystem.Read documentation →
Memory and process stateClaude Managed AgentsNot established in this reviewSandbox0Experimental memory checkpoints can preserve compatible process state. Use memory: true on both pause and resume on a compatible deployment. A filesystem checkpoint alone does not preserve running processes.Read documentation →

Online RootFS growth

On growth-enabled images, Sandbox0 automatically expands the writable RootFS as free space runs low, within a configured sparse logical ceiling up to 64 TiB. Agent processes keep running. Growth is enabled in the qualified Cloud region; confirm activation for other regions. Existing images and snapshots retain their captured storage geometry. The ceiling is logical capacity, not preallocated host disk.

The Anthropic-managed cloud sandbox reference lists a disk up to 10 GB. Its reusable environment configuration and session state do not establish automatic online RootFS expansion.

Files while compute is paused

Sandbox0's Files API reads persistent files without resuming compute. Filesystem-only pauses also permit edits; retained-memory pauses are read-only and reject mutations with 409. SSH, SFTP, file watching, and runtime-only mounts require running compute.

See paused file operations →

An environment configuration is not a shared computer

Claude environments define reusable packages and network settings. Each new session still receives a fresh isolated cloud container; sessions do not share filesystem state through the environment ID. Choose how an evolving toolchain and user files should carry across independent tasks.

Source 1 ↗

Session state and RootFS growth are separate questions

Managed Agents retains state across interactions within a session. The cloud reference lists up to 8 GB RAM and 10 GB disk. A larger or differently controlled execution environment requires evaluating another environment option; these specifications do not establish an automatically expanding root disk.

Source 1 ↗Source 2 ↗

A session-hour is a harness meter

Managed Agents charges runtime only while a session is running, plus model tokens and applicable tools. That session-hour is not a vCPU-hour or a GiB-hour. Sandbox0’s compute and retained-storage prices describe the machine layer; model and harness costs must be added to the application budget.

Source 1 ↗Source 2 ↗

Pricing

Compare billing models, then price your workload

CPU allocation, memory, billing minimums, disk, plan fees, and supported workload differ. These meters are not equal-performance machine quotes. Confirm region, resource units, and included allowances before estimating a total.

Claude Managed Agents

Pricing reviewed 2026-10-18

Managed session runtime
$0.08 per session-hour
Measured to the millisecond while status is running. Idle, rescheduling, and terminated time do not accrue this runtime meter.
Rate source ↗
Model tokens
Additional usage at the selected Claude model’s rates
Rate source ↗
Session web search
$10 per 1,000 searches
Rate source ↗

Model speed, prompt caching, inference geography, and other applicable tool charges can change the total. Sandbox0’s infrastructure price does not include an equivalent managed agent harness or model tokens.

Check current Claude Managed Agents pricing ↗

Sandbox0

$0.015/GiB-hour compute (billed by the second at approximately $0.000004167/GiB-second), plus $0.02/GiB-month of retained incremental RootFS and memory checkpoint data. Shared base images and platform recovery retention are excluded; paused sandboxes accrue storage charges only.

Compute / GiB-hour
$0.015
Retained data / GiB-month
$0.02
Paused compute
$0.00

A 4 GiB agent, 100 running hours

$6.00 compute

4 GiB × 100 hours, billed by the second. Keeping 20 GiB of billable incremental data for a full billing month adds $0.40. CPU is derived from memory by the platform; choose a tier that fits your workload.

Understand storage billing →

Before migrating from Claude Managed Agents

  1. Separate reusable agent/environment configuration, session conversation events, uploaded files, and session-produced files.
  2. Choose or implement the harness and model integration that will run on Sandbox0; port tool permissions, network policy, and credentials.
  3. Export needed session outputs before deleting the source session, then test repeated tasks, installed packages, RootFS growth, and paused file access.

Common questions

Is Sandbox0 a drop-in Claude Managed Agents replacement?

Evaluate API compatibility and product scope. A shared sandbox category does not make SDKs, lifecycle semantics, or limits interchangeable.

Does keeping files also keep a running agent?

Filesystem state and volatile process state are separate. Sandbox0 requires explicit compatible memory checkpoints to preserve running processes; its default filesystem resume starts fresh processes.

Sources and review scope

The Boat team's Battleships directory is the discovery source. References below describe the product and plan discussed on this page. Check current availability, regional terms and billing units before migrating. Where the cited material does not establish a capability or price, the comparison identifies that uncertainty.

Battleships research record ↗platform.claude.com/docs/en/managed-agents/environments ↗platform.claude.com/docs/en/managed-agents/overview ↗platform.claude.com/docs/en/managed-agents/cloud-sandboxes-reference ↗platform.claude.com/docs/en/about-claude/pricing ↗/pricing ↗Sandbox0 RootFS capacity →

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