pi-e2b-extension-js

Pi with its tools in an E2B sandbox (JavaScript)

Pi runs on your machine; its tools run in an E2B sandbox. The @e2b/pi extension gives Pi a --e2b flag: the agent works on a copy of your project in a sandbox, can't touch your files, processes or credentials, and you bring its changes back with /e2b pull.

This example drives that flow from a script with Pi's SDK, so you can run it with one command and read every step in your terminal:

1. Start. A fresh git checkout, sandbox-roasters, is created on your machine. The sandbox starts with the first prompt and gets a copy of the working tree.
2. Work. Pi builds a one-page site for a coffee roaster. bash, read, write and edit run in the sandbox; preview_url turns port 8080 into a public https://8080-<sandbox>.e2b.app link.
3. Pull. /e2b pull shows the diff stat and applies it to your checkout. git status then shows index.html on your machine.

  E2B × Pi  @e2b/pi
  ────────────────────────────────────────────────────────────
  Task      Build a one-page site for Sandbox Roasters, a small coffee roaster: ...
  Project   /tmp/pi-e2b-2KlBlj/sandbox-roasters
  Model     anthropic/claude-sonnet-5-5

  ◆ E2B sandbox igjk3mmyvz8u15tikweg1 created in 0.7s
    └  1.0s  project uploaded: your git working tree, unpacked and committed as the baseline
  ● preview_url  port=8080
    └  0.0s  https://8080-igjk3mmyvz8u15tikweg1.e2b.app
  ● write  index.html  3,902 chars
    └  0.7s  Successfully wrote to /home/user/sandbox-roasters/index.html
  ● bash  cd /home/user/sandbox-roasters && (nohup python3 -m http.server 8080 --bind 0.0.0.0 ...
    └  1.5s  200

  Pi

  The Sandbox Roasters site is up on port 8080: https://8080-igjk3mmyvz8u15tikweg1.e2b.app
  ...

  Pull changes
  Apply to /tmp/pi-e2b-2KlBlj/sandbox-roasters?

  index.html | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   1 file changed, 78 insertions(+)
  → Yes (answered by the script)

  ◆ Pulled. Review with git diff.

  sandbox-roasters ❯ ls && git status --short
  index.html
  README.md
  ?? index.html

  ✓ Done in 21s · 3 tool calls

How to run the example

1. Set the API keys

Copy .env.example to .env and fill in E2B_API_KEY and ANTHROPIC_API_KEY.

2. Install dependencies (Node 22.19 or newer)

npm install

3. Run the script

npm start                                   # the Sandbox Roasters site
npm start -- "Write a FastAPI hello world, run it on port 8000 and share the link"   # your own task

In a terminal the script waits for Enter before it kills the sandbox, so you can open the preview URL. Piped or in CI it kills it at once.

How it works

src/index.ts is what cd sandbox-roasters && pi --e2b does, in SDK calls:

CLI	SDK
pi install npm:@e2b/pi	new DefaultResourceLoader({ additionalExtensionPaths: [<@e2b/pi>] })
pi --e2b	session.extensionRunner.setFlagValue('e2b', true), then session.bindExtensions(...) fires session_start and the extension swaps in its sandbox tools
typing the task	session.prompt(task)
/e2b pull, answering Yes	session.prompt('/e2b pull'), with a UI context whose confirm returns true
/e2b kill	session.prompt('/e2b kill')

The session is in memory, like pi --no-session, so the sandbox is created to be killed rather than paused. src/tui.ts only prints: the tool call trace, Pi's answer and the extension's dialogs.

Use it interactively

The everyday way to use the extension is Pi's own TUI, which is what the recording above shows:

npm install -g @earendil-works/pi-coding-agent
pi install npm:@e2b/pi
cd my-project
pi --e2b

/e2b shows the sandbox and what is not pulled yet, /e2b pull --branch commits the changes on a local pi/<session> branch instead, and pi --e2b -c resumes the same sandbox later. See the extension README for all flags and commands.