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Field Guide

06 · Field guide

ContextECF Halo

Prompt safety coaching that never leaves your machine.

Ready

What it does

Halo watches the moment before a prompt is sent in the browser. If a request looks risky — sensitive content, an over-broad ask, an unsafe destination — it coaches the person instead of silently blocking them.

The runtime is local. A Control Tower runs on 127.0.0.1 and holds a privacy-preserving receipt of decisions; the Chrome extension talks only to that local runtime, never to a remote service.

It is the human-facing counterpart to the machine-facing tools above: same governance model, applied to the person typing.

Who it’s for

Anyone using browser AI tools inside an organization with data-handling rules.

What you need

  • ·Node.js 20.20 or newer
  • ·Chrome for the paired extension (optional)

Quick start

# install & run$ npm install -g @contextecf/guardian-cli$ guardian setup$ guardian open

Requires Node.js 20.20+. guardian open launches the local Control Tower in your browser.

Paired with the ContextECF Halo Chrome extension for in-browser prompt coaching, connected to the local runtime only.

Step by step

  1. 01

    Install the runtime

    The guardian CLI is the local runtime behind Halo.

    $ npm install -g @contextecf/guardian-cli
  2. 02

    Run setup

    setup creates a local profile and runs a health check. A WARN on first run flags optional hardening, not a failure.

    $ guardian setup
  3. 03

    Open the Control Tower

    The Control Tower is a local page on 127.0.0.1:4317 showing decisions and receipts.

    $ guardian open
  4. 04

    Connect the extension

    Open the ContextECF Halo extension and click Connect. No setup code is needed — it discovers the local runtime.

What you’ll see

Project Guardian setup complete.Profile: ~/.local/share/guardianDoctor: WARNControl Tower: http://127.0.0.1:4317/control-towerBrowser connection: ready for ContextECF HaloExtension setup: open ContextECF Halo and click Connect. No setup code needed. Opening: http://127.0.0.1:4317/control-tower

"Doctor: WARN" on first run is normal — it flags optional hardening steps (OS key storage, daemon supervision) you haven't set up yet, not a failure. If no browser opens automatically (e.g. over SSH), the Control Tower URL above still works if you open it yourself.

If something goes wrong

No browser opened.

Common over SSH. Open http://127.0.0.1:4317/control-tower yourself; the runtime is already listening.

The extension will not connect.

Confirm guardian setup completed and the Control Tower URL loads locally; the extension only talks to that local runtime.

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