Run a code snippet in a sandboxed interpreter

POST /v1/exec

Executes a program in a throwaway sandbox and answers with what it printed and what it left behind.

lang names one of the thirteen the sandbox image carries — py, js, ts, bash, r, php, go, rs, c, cpp, java, d, f90 — and code is the whole program, not a fragment: a compiled language is compiled and then run, an interpreted one is interpreted, and args becomes the program's own argv either way. Nothing is installed for you; the image is the environment.

A PROGRAM THAT FAILS IS A SUCCESSFUL CALL. A non-zero exit answers 200 with the diagnostics on stderr, because "the code threw" and "the interpreter is down" are different facts a caller renders differently. Only the second is an error status.

Runs are stateful through session_id. Omit it and the run gets a fresh sandbox whose id comes back on the answer; pass that id again and the next run sees the same filesystem, so a program can write a file one call and read it the next. files names bytes already uploaded to a session (POST /v1/exec/upload), copied in before the program starts. files on the ANSWER is what the program created or changed, by comparison against a marker taken at start — so it is the run's real output, not a listing of the directory — and each is fetched from GET /v1/exec/download/{session}/{name}.

The tenant is the caller's, never the body's, at every door. A typed op is also an MCP tool and an op-plane op; MCP's tools/call invokes it directly, with no route and therefore no middleware, so nothing there could have checked a credential. tenantOf refuses a context carrying neither a validated principal nor exec's own admission marker, so those doors fail closed without a second gate to keep in step.

Request

11 fields, body application/json (required).

Response

200 body — 8 fields.

Failure carries the platform error shape — see Errors.

Examples

hanzo exec create \
  --code <code> \
  --lang <lang>

import { Configuration, ExecApi } from 'hanzoai';

const api = new ExecApi(new Configuration({ accessToken: process.env.HANZO_API_KEY }));
const { data } = await api.postExec({ lang: "<lang>", code: "<code>" });

from hanzoai.cloud import ApiClient, Configuration
from hanzoai.cloud.api import ExecApi

client = ApiClient(Configuration(access_token=os.environ["HANZO_API_KEY"]))
result = ExecApi(client).post_exec(lang="<lang>", code="<code>")

cfg := cloud.NewConfiguration()
cfg.AddDefaultHeader("Authorization", "Bearer "+os.Getenv("HANZO_API_KEY"))
client := cloud.NewAPIClient(cfg)

resp, _, err := client.ExecAPI.PostExec(context.Background()).Execute()
if err != nil {
	return err
}

use hanzo_cloud::apis::{configuration::Configuration, exec_api};

let mut cfg = Configuration::new();
cfg.bearer_access_token = std::env::var("HANZO_API_KEY").ok();

let result = exec_api::post_exec(&cfg, Default::default()).await?;

import ai.hanzo.cloud.ApiClient;
import ai.hanzo.cloud.api.ExecApi;

ApiClient client = new ApiClient();
client.setRequestInterceptor(b -> b.header("Authorization", "Bearer " + System.getenv("HANZO_API_KEY")));

var result = new ExecApi(client).postExec();

curl -X POST https://api.hanzo.ai/v1/exec \
  -H "Authorization: Bearer $HANZO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
       "lang": "<lang>",
       "code": "<code>"
     }'

curl -X POST https://api.hanzo.ai/v1/mcp \
  -H "Content-Type: application/json" \
  -d '{
       "jsonrpc": "2.0",
       "id": 1,
       "method": "tools/call",
       "params": {
         "name": "describe",
         "arguments": {
           "op": "get_download"
         }
       }
     }'

Exec API · All Hanzo APIs · Interactive reference