repld-tool 0.0.18

Persistent Python runtime with MCP channel push. Dev shell and autonomous-agent substrate in one package.

repld

A live Python kernel for your agent. Shared namespace, channel push, a scriptable browser, and one-off code that hardens into tools.

uv tool install repld-tool

What it does

• Persistent kernel — one long-running Python process in your project directory. State survives across turns.
• Shared namespace — you and the agent operate on the same __main__. Inspect its variables, patch its functions, take over mid-task.
• Channel push — long jobs, timers, file watchers, and webhooks push back as notifications. The agent reacts; it never polls.
• Browser — attach to your logged-in Chrome via CDP. Every mutation settles, then returns the accessibility tree, network delta, and console delta.
• Gists — plain Python files the kernel hot-reloads. Reverse-engineer an API once, import it forever, link it across projects, register it as an MCP tool.

Install

uv tool install repld-tool        # global install (recommended)

cd your-project
repld init                         # writes .mcp.json + updates .gitignore
repld                              # starts the kernel

Project-local alternative: uv add --dev repld-tool, then point .mcp.json at uv run repld bridge.

repld init produces:

{
  "mcpServers": {
    "repld": { "type": "stdio", "command": "repld", "args": ["bridge"] }
  }
}

Quick example

# runs inline — result returned immediately
import httpx
httpx.get("https://api.example.com/status").json()

# long-running — returns task_id, pushes channel notification on completion
await asyncio.sleep(30)
notify("done", kind="migration")

Autonomous worker:

@every(300)
async def check_overdue():
    for inv in await erp.get_overdue():
        notify(f"Overdue: {inv.customer} — {inv.amount}",
               kind="overdue", invoice_id=inv.id)

The kernel runs the watcher; the agent reacts to each channel notification.

With an existing app

repld inherits your project's environment. A repl.py at the project root:

from myapp.main import app
from myapp.db import async_session_maker
import asyncio, uvicorn

asyncio.create_task(uvicorn.Server(
    uvicorn.Config(app, host="127.0.0.1", port=8000, log_level="warning")
).serve())

session = async_session_maker()
print("FastAPI on :8000, db session ready")

repld --init repl.py

The agent now has a live handle on your running app: inspect routes, query the ORM, call handlers directly.

Tools

Core:

Tool	What it does
exec	Execute Python. Returns inline within timeout (default 2s); otherwise returns task_id and pushes channel on completion.
get_task	Status + head/tail preview of a running task's output.
cancel	Cancel a running task by id.

Browser (requires uv tool install repld-tool[browser]):

Tool	What it does
browser_watch	Watch URL pattern, auto-attach matching tabs.
browser_tabs	List attached tabs.
browser_pages	List all Chrome targets.
browser_js	Evaluate JavaScript (REPL semantics, top-level await).
browser_network	Query captured traffic (HAR-style, DuckDB).
browser_request	Full HAR entry — headers, postData, timing.
browser_body	Response body for a captured request.
browser_fetch	In-page fetch (inherits auth/cookies).
browser_click	Click element (auto-waits, returns observation).
browser_type	Type into element.
browser_key	Send key press (Enter, Escape, etc).
browser_navigate	Navigate tab to URL.
browser_open	Open new tab and navigate.
browser_tree	Accessibility tree snapshot.
browser_console	Query console logs and exceptions.
browser_screenshot	Capture page screenshot.
browser_cdp	Raw CDP passthrough.
browser_clear	Reset captured network/console.
browser_detach	Remove watch pattern, detach tabs.

Output from every cell spills to $XDG_RUNTIME_DIR/repld/ — the inline response carries a head/tail preview plus the spill path. Use standard Read/Grep tools for full output.

Kernel builtins

notify(content, **meta)              # channel push to the agent
ask(prompt)                          # block on free-form human input
confirm(prompt)                      # block on yes/no
choose(prompt, options)              # block on pick-one
defer(coro, label=None)              # fire-and-forget, channel push on completion
@every(seconds)                      # periodic ticker, fn.cancel() to stop

Browser

repld[browser] attaches to Chrome via CDP (--remote-debugging-port=9222). You log in normally; the agent sees your traffic, discovers the API surface, and works with your authenticated sessions.

tab = await browser.get("*example.com*")     # find tab by URL glob
tab = await browser.open("https://...")      # open new tab
await browser.watch("*pattern*")             # auto-attach matching tabs

await tab.js("document.title")               # eval JS (top-level await works)
await tab.fetch("/api/data")                 # in-page fetch (inherits session)
await tab.click("#submit")                   # click, settle, return observation
await tab.type_text("#search", "query")      # type into element
tab.network(url="*api*")                     # query captured traffic

Body capture via Fetch interception means login flows, redirects, and CSRF exchanges are never lost. See docs/browser.md for the full design.

Gists

Gists are Python modules in ./gists/ (project) or ~/.repld/gists/ (global) that wrap anything into a callable API. The browser supplies auth; the gist captures the pattern.

# gists/myapp.py
"""MyApp — accounts and transactions."""

class MyApp:
    def __init__(self, tab): self._tab = tab

    @classmethod
    async def connect(cls):
        from __main__ import browser
        tab = await browser.get("*myapp.com*")
        return cls(tab)

    async def accounts(self):
        return (await self._tab.fetch("/api/accounts"))["body"]

from myapp import MyApp
app = await MyApp.connect()
await app.accounts()

Re-importing after edits auto-reloads. Gists can declare dependencies (__repld_deps__), register MCP tools (__repld_tools__), and link across projects (repld gist add <name>). See repld help gists for details.

Scope

repld executes arbitrary Python in your project environment. It is a dev-time tool — never a runtime dependency. The IPC socket is localhost-only with user-only permissions.

Channel push requires Claude Code's --channels flag (research preview).

License

MIT