remiss

remiss is a Slack desktop client mod for macOS and Windows. It injects renderer-side plugins (e.g. syntax highlighting) into Slack via Chrome DevTools Protocol.

Requirements

• Bun >= 1.0
• Slack desktop for macOS or Windows

Installation

bun install -g remiss

Then install the resident Remiss agent:

remiss install

The agent runs at login, starts Slack with CDP when needed, injects the payload, then idles while Slack is open.

Usage

# Install / remove the background agent
remiss install
remiss uninstall

# Dev mode — launches Slack with CDP, injects payload, and hot-reloads on changes
remiss dev

# One-shot inject via DevTools (resets on Slack reload)
remiss cdp

# Build the payload bundle
remiss build-payload

# Launch Slack with remote debugging port for manual inspection
remiss inspect

While dev is running, editing any file under payload/ triggers a hot reload. Press r to hard-reload Slack. Ctrl+C stops the dev session but leaves Slack running.

Current plugins

Syntax Highlighting

Adds Shiki-powered highlighting to Slack code blocks.

To use it, type ``` in Slack, then once Slack renders the code block, put the language extension on the first line and your code below it.

Example:

```
ts
const hello: string = "world";
```

Supported languages: JavaScript, TypeScript, JSON, Python, Bash, HTML/XML, CSS, SQL, Go, and Rust.

Supported aliases: js, jsx, mjs, cjs, ts, tsx, json5, py, sh, shell, zsh, htm, xml, golang, rs.

Project structure

• payload/ — renderer plugins (injected into Slack's DOM)
• src/cdp/ — Chrome DevTools Protocol client and injection logic
• src/dev/ — dev console bridge, file watcher, and keypress handler