docs: Add Leap0 sandbox integration docs

src/oss/deepagents/sandboxes.mdx

@@ -100,6 +100,12 @@ For provider-specific setup, authentication, and lifecycle details, see [sandbox
         <img className="w-5 h-5" src="/images/brand/docs-favicon.png" alt="" />
         <span className="font-semibold">LangSmith</span>
     </a>
+
+    <a href="/oss/integrations/providers/leap0" className="flex items-center justify-center gap-1.5 p-2 rounded-lg border border-gray-200 dark:border-gray-700 hover:border-gray-300 dark:hover:border-gray-600 no-underline">
+        <img className="block dark:hidden w-5 h-5" src="/images/providers/light/leap0.svg" alt="" />
+        <img className="hidden dark:block w-5 h-5" src="/images/providers/dark/leap0.svg" alt="" />
+        <span className="font-semibold">Leap0</span>
+    </a>
 </div>
 :::
 

src/oss/javascript/integrations/providers/leap0.mdx

@@ -0,0 +1,122 @@
+---
+title: "Leap0"
+sidebarTitle: "Leap0"
+description: "Use Leap0 sandbox backends with Deep Agents for isolated code execution with fast cold starts"
+---
+
+[Leap0](https://leap0.dev) provides cloud sandboxes for AI agents: isolated compute, filesystem, and network boundaries, with sandboxes that start in about 200ms. See the [Leap0 docs](https://leap0.dev/docs) for signup, API keys, and platform details.
+
+The LangChain integration is published as [`@leap0/langchain-leap0`](https://www.npmjs.com/package/@leap0/langchain-leap0). It implements the Deep Agents sandbox backend and pairs with the [`leap0`](https://www.npmjs.com/package/leap0) TypeScript SDK.
+
+## Setup
+
+<CodeGroup>
+    ```bash npm
+    npm install @leap0/langchain-leap0 deepagents leap0
+    ```
+
+    ```bash yarn
+    yarn add @leap0/langchain-leap0 deepagents leap0
+    ```
+
+    ```bash pnpm
+    pnpm add @leap0/langchain-leap0 deepagents leap0
+    ```
+</CodeGroup>
+
+`@leap0/langchain-leap0` declares **peer dependencies** on `deepagents` and `leap0`; install them alongside the integration package as shown above.
+
+### Authentication
+
+```bash
+export LEAP0_API_KEY="your-key"
+```
+
+## Create a sandbox backend
+
+Create a sandbox with the Leap0 SDK, then connect it with `Leap0Sandbox.fromConnected`.
+
+:::js
+```typescript
+import { Leap0Client } from "leap0";
+import { Leap0Sandbox } from "@leap0/langchain-leap0";
+
+const client = new Leap0Client();
+const sandbox = await client.sandboxes.create();
+const backend = Leap0Sandbox.fromConnected(client, sandbox);
+
+try {
+  const result = await backend.execute("echo 'Hello from Leap0'");
+  console.log(result.output);
+} finally {
+  try {
+    await sandbox.delete();
+  } finally {
+    await client.close();
+  }
+}
+```
+:::
+
+### One-step create
+
+To have the integration create a `Leap0Client`, provision a sandbox, and own teardown:
+
+:::js
+```typescript
+import { Leap0Sandbox } from "@leap0/langchain-leap0";
+
+const backend = await Leap0Sandbox.create({
+  leap0Config: {},
+  createParams: { templateName: "base" },
+});
+
+try {
+  const result = await backend.execute("echo hello");
+  console.log(result.output);
+} finally {
+  await backend.close(); // deletes sandbox and closes the client
+}
+```
+:::
+
+## Usage with Deep Agents
+
+:::js
+```typescript
+import { createDeepAgent } from "deepagents";
+import { ChatAnthropic } from "@langchain/anthropic";
+import { Leap0Sandbox } from "@leap0/langchain-leap0";
+import { Leap0Client } from "leap0";
+
+const client = new Leap0Client();
+const sandbox = await client.sandboxes.create();
+const backend = Leap0Sandbox.fromConnected(client, sandbox);
+
+try {
+  const agent = createDeepAgent({
+    model: new ChatAnthropic({ model: "claude-sonnet-4-20250514" }),
+    systemPrompt: "You are a coding assistant with sandbox access.",
+    backend,
+  });
+
+  const result = await agent.invoke({
+    messages: [
+      { role: "user", content: "Create a hello world Python script and run it" },
+    ],
+  });
+} finally {
+  try {
+    await sandbox.delete();
+  } finally {
+    await client.close();
+  }
+}
+```
+:::
+
+## Cleanup
+
+You are responsible for managing the sandbox lifecycle via the Leap0 SDK unless you use `Leap0Sandbox.create` and `backend.close()` as above.
+
+See also: [Sandboxes](/oss/deepagents/sandboxes).

src/oss/javascript/integrations/sandboxes/index.mdx

@@ -29,6 +29,12 @@ Sandboxes provide isolated execution environments for running agent-generated co
         <img className="w-5 h-5" src="/images/brand/docs-favicon.png" alt="" />
         <span className="font-semibold">LangSmith</span>
     </a>
+
+    <a href="/oss/integrations/providers/leap0" className="flex items-center justify-center gap-1.5 p-2 rounded-lg border border-gray-200 dark:border-gray-700 hover:border-gray-300 dark:hover:border-gray-600 no-underline">
+        <img className="block dark:hidden w-5 h-5" src="/images/providers/light/leap0.svg" alt="" />
+        <img className="hidden dark:block w-5 h-5" src="/images/providers/dark/leap0.svg" alt="" />
+        <span className="font-semibold">Leap0</span>
+    </a>
 </div>
 
 If you'd like to contribute a sandbox, see [Implement a sandbox integration](/oss/contributing/implement-langchain#sandboxes).

src/oss/python/integrations/providers/leap0.mdx

@@ -0,0 +1,13 @@
+---
+title: "Leap0 integrations"
+sidebarTitle: "Leap0"
+description: "Integrate with Leap0 using LangChain Python."
+---
+
+[Leap0](https://leap0.dev) provides cloud sandboxes for AI agents: isolated compute, filesystem, and network boundaries, with sandboxes that start in about 200ms. See the [Leap0 docs](https://leap0.dev/docs) for signup, API keys, and platform details.
+
+<Columns cols={2}>
+    <Card title="Leap0Sandbox" href="/oss/integrations/sandboxes/leap0" cta="Get started" icon="terminal" arrow>
+        Leap0 sandbox backend for Deep Agents.
+    </Card>
+</Columns>

src/oss/python/integrations/sandboxes/index.mdx

@@ -35,6 +35,12 @@ Sandboxes provide isolated execution environments for running agent-generated co
         <img className="w-5 h-5" src="/images/brand/docs-favicon.png" alt="" />
         <span className="font-semibold">LangSmith</span>
     </a>
+
+    <a href="/oss/integrations/sandboxes/leap0" className="flex items-center justify-center gap-1.5 p-2 rounded-lg border border-gray-200 dark:border-gray-700 hover:border-gray-300 dark:hover:border-gray-600 no-underline">
+        <img className="block dark:hidden w-5 h-5" src="/images/providers/light/leap0.svg" alt="" />
+        <img className="hidden dark:block w-5 h-5" src="/images/providers/dark/leap0.svg" alt="" />
+        <span className="font-semibold">Leap0</span>
+    </a>
 </div>
 
 If you'd like to contribute a sandbox, see [Implement a sandbox integration](/oss/contributing/implement-langchain#sandboxes).

src/oss/python/integrations/sandboxes/leap0.mdx

@@ -0,0 +1,80 @@
+---
+title: "Leap0Sandbox integration"
+description: "Integrate with the Leap0Sandbox sandbox backend using LangChain Python."
+---
+
+[Leap0](https://leap0.dev) provides cloud sandboxes for AI agents: isolated compute, filesystem, and network boundaries, with sandboxes that start in about 200ms. See the [Leap0 docs](https://leap0.dev/docs) for signup, API keys, and platform details.
+
+Set `LEAP0_API_KEY` in your environment before running the examples below.
+
+## Installation
+
+<CodeGroup>
+```bash pip
+pip install langchain-leap0
+```
+
+```bash uv
+uv add langchain-leap0
+```
+</CodeGroup>
+
+## Create a sandbox backend
+
+In Python, you create the sandbox using the provider SDK, then wrap it with the [deepagents backend](/oss/deepagents/backends).
+
+```python
+from leap0 import Leap0Client
+
+from langchain_leap0 import Leap0Sandbox
+
+client = Leap0Client()
+sandbox = client.sandboxes.create()
+backend = Leap0Sandbox(client=client, sandbox=sandbox)
+
+try:
+    result = backend.execute("echo hello")
+    print(result.output)
+finally:
+    client.sandboxes.delete(sandbox)
+    client.close()
+```
+
+## Use with Deep Agents
+
+```python
+from leap0 import Leap0Client
+from langchain_anthropic import ChatAnthropic
+
+from deepagents import create_deep_agent
+from langchain_leap0 import Leap0Sandbox
+
+client = Leap0Client()
+sandbox = client.sandboxes.create()
+backend = Leap0Sandbox(client=client, sandbox=sandbox)
+
+agent = create_deep_agent(
+    model=ChatAnthropic(model="claude-sonnet-4-20250514"),
+    system_prompt="You are a coding assistant with sandbox access.",
+    backend=backend,
+)
+
+try:
+    result = agent.invoke(
+        {
+            "messages": [
+                {"role": "user", "content": "Create a hello world Python script and run it"}
+            ]
+        }
+    )
+finally:
+    client.sandboxes.delete(sandbox)
+    client.close()
+```
+
+## Cleanup
+
+You are responsible for managing the sandbox lifecycle via the Leap0 SDK.
+When you are done, delete the sandbox and close the client.
+
+See also: [Sandboxes](/oss/deepagents/sandboxes).

src/snippets/deepagents-sandbox-basic-py.mdx

@@ -180,4 +180,49 @@
         ```
 
     </Tab>
+    <Tab title="Leap0">
+
+        <CodeGroup>
+            ```bash pip
+            pip install langchain-leap0
+            ```
+
+            ```bash uv
+            uv add langchain-leap0
+            ```
+        </CodeGroup>
+
+        ```python
+        from deepagents import create_deep_agent
+        from langchain_anthropic import ChatAnthropic
+        from langchain_leap0 import Leap0Sandbox
+        from leap0 import Leap0Client
+
+        client = Leap0Client()
+        sandbox = client.sandboxes.create()
+        backend = Leap0Sandbox(client=client, sandbox=sandbox)
+
+        agent = create_deep_agent(
+            model=ChatAnthropic(model="claude-sonnet-4-6"),
+            system_prompt="You are a Python coding assistant with sandbox access.",
+            backend=backend,
+        )
+
+        try:
+            result = agent.invoke(
+                {
+                    "messages": [
+                        {
+                            "role": "user",
+                            "content": "Create a small Python package and run pytest",
+                        }
+                    ]
+                }
+            )
+        finally:
+            client.sandboxes.delete(sandbox)
+            client.close()
+        ```
+
+    </Tab>
 </Tabs>