Apps — Plexi Docs

Plexi apps render into panes through PGAP. The Python SDK is the default authoring path.

Python apps are native subprocesses. Capabilities gate host APIs such as net.http, secrets.get, and ai.query; they are not a Python process sandbox.

Create an App

From inside a Plexi workspace:

plexi app init my-app

Outside a workspace, use --global.

This scaffolds a new app folder with:

my-app/
  manifest.toml    ← capabilities, entry point, metadata
  main.py          ← your app code
  tests/test_app.py ← AppHarness smoke tests
  .venv/           ← isolated Python runtime

Validate the app and write screenshots:

plexi app check ./my-app --png-dir /tmp/my-app-shots

Open an App

Pass the path to the app folder:

plexi app open ./my-app

The app opens in a pane. Use this during development; no marketplace install is required.

The App Pattern

SDK v3 apps are module-level init, update, and view functions. view() returns a component tree and must stay pure:

#!/usr/bin/env python3
from __future__ import annotations

from plexi_sdk import state
from plexi_sdk.effects import SetState, SetTitle
from plexi_sdk.events import KeyEvent
from plexi_sdk.ui import AppBar, Column, FooterKeys, Text


def init(size, args):
    return [SetTitle("My App"), SetState({"count": 0})]


def update(event):
    if isinstance(event, KeyEvent) and event.key == "return" and event.pressed:
        return [SetState({"count": state.get("count", 0) + 1})]
    return []


def view():
    return Column([
        AppBar("My App"),
        Text(str(state.get("count", 0)), bold=True),
        FooterKeys([("return", "increment")]),
    ], grow=True)

Canvas apps also return from view(): use Canvas(...) components and RenderFrame events for animation.

Capabilities

Declare what your app needs in manifest.toml:

[app.capabilities]
capabilities = ["secrets.get", "net.http"]

Common capabilities: secrets.get, net.http, fs.read, fs.write, ai.query, audio.record, timer.

Logging

Use plexi_sdk.log from init() or update(). Log lines are tagged with the app process in the host log.

from plexi_sdk import log


def init(size, args):
    log.info("my-app initialized")
    return []