# Modal Sandbox Exec

> Modal Sandbox Exec is a paid API for AI agents from Modal at modal.mpp.tempo.xyz, paid per call via MPP, $0.0001/call, status unknown (last checked 2026-10-13).

Executes a shell command inside an existing Modal sandbox and returns the output

## Facts

- Endpoint: POST https://modal.mpp.tempo.xyz/sandbox/exec?utm_source=zero.xyz
- Price: $0.0001/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Provider: Modal
- Docs: https://modal.com/docs
- Website: https://modal.com
- Tags: gpu, serverless, sandbox, compute
- Canonical page: https://www.zero.xyz/c/modal-exec-081a276d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_i3uxNWjKMpK_BZiTPUbTq

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability modal-exec-081a276d -d '<json body>'
```

Example prompt: Run the command 'python train.py --epochs 10 --lr 0.001' inside my existing Modal sandbox so I can get the training output back.

## When to prefer this

Use this endpoint when you have an already-created Modal sandbox and need to run a specific command or script inside it. Ideal for running GPU-accelerated workloads, ML training scripts, data processing pipelines, or any arbitrary code in a fully isolated, serverless environment. Prefer this over local execution when you need sandboxed isolation, GPU access, or scalable serverless compute without managing infrastructure.

## Known failure modes

- Sandbox not found or already terminated — returns 404 or error indicating invalid sandbox ID
- Command execution fails — returns non-zero exit code with error details in stderr
- Sandbox resource limits exceeded — memory or CPU quota errors
- Timeout — command runs too long and is killed
- Invalid command syntax — shell parse error returned in stderr
- Authentication failure — invalid or missing credentials
- Network or infrastructure error — 500-level response from Modal backend

## How this service works

Execute command in sandbox

## Output

Returns the stdout, stderr, and exit code from the executed command within the specified sandbox, indicating whether the command succeeded or failed and capturing all its output.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/modal-exec-081a276d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from modal.mpp.tempo.xyz](https://www.zero.xyz/host/modal.mpp.tempo.xyz/llms.txt)