sandbox-next

1# Sandbox SDK — `@next` (1.0 preview)
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3Isolated Linux environments on [Cloudflare Containers](https://developers.cloudflare.com/containers/index.md), driven from Workers.
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5**Prefer preview docs and installed `@next` types over memory.** APIs change; this skill is a gate, a contract, and a retrieval map—not a full manual.
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7We recommend **new projects** on this line. Apps still on the default package use **`sandbox-stable`**. Port only when asked, via **`sandbox-migrate-to-next`**.
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9## 1. Gate — confirm the package line
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11Before writing code, inspect the app:
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13| Check | Must match |
14| ----- | ---------- |
15| npm dependency | `@cloudflare/sandbox@next` (or another preview tag) |
16| Container image | Same line (e.g. `cloudflare/sandbox:next`, `next-python`) |
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18| If you find… | Action |
19| ------------ | ------ |
20| Default `@cloudflare/sandbox` (no `@next`) | **Stop.** Load **`sandbox-stable`**. Do not apply this skill’s APIs. |
21| User wants to port stable → `@next` | **Stop.** Load **`sandbox-migrate-to-next`**. |
22| Self-deployed **bridge** only | Bridge is **not** on the 1.0 preview line yet. Keep bridge on stable package + image. [Bridge (stable)](https://developers.cloudflare.com/sandbox/sdk/bridge/index.md) |
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24Never mix an `@next` Worker package with a stable container image (or the reverse).
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26Skills install: [Agent setup](https://developers.cloudflare.com/agent-setup/index.md) · [cloudflare/skills](https://github.com/cloudflare/skills)
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28## 2. Contract — non-negotiables
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