Python REPL

Runs model-generated Python through the agent’s sandbox by calling sandbox.execute_code(code, "python3") (sandbox.executeCode(code, 'python3') in TypeScript). It returns output (stdout), error (stderr, including tracebacks), and exit_code. Each call runs in a fresh interpreter, so variables, imports, and definitions do not persist across calls. Files written to the sandbox filesystem do persist, so the model can checkpoint intermediate results to disk and load them in a later call.

Supported in: Node.js on Unix/Linux/macOS (TypeScript), Python.

Security Warning

This tool executes arbitrary Python code. Without a Sandbox, code runs with the full permissions of the process. Only use with trusted input and consider running in a sandboxed environment for production.

TypeScript

import { Agent } from '@strands-agents/sdk'
import { pythonRepl } from '@strands-agents/sdk/vended-tools/python-repl'

const agent = new Agent({ tools: [pythonRepl] })
await agent.invoke(
  'Use python_repl to compute the first 10 Fibonacci numbers and print them.'
)

Python

from strands import Agent
from strands.vended_tools import python_repl

agent = Agent(tools=[python_repl])
agent("Use python_repl to compute the first 10 Fibonacci numbers and print them.")

Bound sandbox or custom interpreter:

TypeScript

import { Agent } from '@strands-agents/sdk'
import { DockerSandbox } from '@strands-agents/sdk/sandbox/docker'
import { makePythonRepl } from '@strands-agents/sdk/vended-tools/python-repl'

const pythonRepl = makePythonRepl(new DockerSandbox({ container: 'my-container' }), {
  language: 'python3.12',
})
const agent = new Agent({ tools: [pythonRepl] })

Python

from strands import Agent
from strands.sandbox.docker import DockerSandbox
from strands.vended_tools import make_python_repl

python_repl = make_python_repl(
    sandbox=DockerSandbox("my-container"),  # bind at creation instead of reading agent.sandbox
    language="python3.12",  # interpreter on the sandbox's PATH
)
agent = Agent(tools=[python_repl])

Full API reference

Tags

tool-authoring26