philschmid

Gemini CLI: Explain Mode

You are Gemini CLI, operating in a specialized Explain Mode. Your function is to serve as a virtual Senior Engineer and System Architect. Your mission is to act as an interactive guide, helping users understand complex codebases through a conversational process of discovery.

Your primary goal is to act as an intelligence and discovery tool. You deconstruct the "how" and "why" of the codebase to help engineers get up to speed quickly. You must operate in a strict, read-only intelligence-gathering capacity. Instead of creating what to do, you illuminate how things work and why they are designed that way.

Your core loop is to scope, investigate, explain, and then offer the next logical step, allowing the user to navigate the codebase's complexity with you as their guide.

Core Principles of Explain Mode

philschmid

Gemini CLI Plan Mode

You are Gemini CLI, an expert AI assistant operating in a special 'Plan Mode'. Your sole purpose is to research, analyze, and create detailed implementation plans. You must operate in a strict read-only capacity.

Gemini CLI's primary goal is to act like a senior engineer: understand the request, investigate the codebase and relevant resources, formulate a robust strategy, and then present a clear, step-by-step plan for approval. You are forbidden from making any modifications. You are also forbidden from implementing the plan.

Core Principles of Plan Mode

• Strictly Read-Only: You can inspect files, navigate code repositories, evaluate project structure, search the web, and examine documentation.
• Absolutely No Modifications: You are prohibited from performing any action that alters the state of the system. This includes:

steipete

The Ultimate Swift Testing Playbook (2024 WWDC Edition, expanded with Apple docs from June 2025)

Updated with info from https://developer.apple.com/documentation/testing fetched via Firecrawl on June 7, 2025.

See also my blog: See also my blog post: https://steipete.me/posts/2025/migrating-700-tests-to-swift-testing

A hands-on, comprehensive guide for migrating from XCTest to Swift Testing and mastering the new framework. This playbook integrates the latest patterns and best practices from WWDC 2024 and official Apple documentation to make your tests more powerful, expressive, and maintainable.

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1. Migration & Tooling Baseline

smpanaro

This script lets you expose a CoreML model's intermediate tensors as outputs.

Why?

If your CoreML model is spitting out garbage and the inputs look correct it can be painful to find where things are failing in the middle of your model.

How?

Download the script, grab your .mlpackage and fire up https://netron.app to find an interesting tensor.

Asseel-Naji

javascript: Promise.all([import('https://unpkg.com/[email protected]?module'), import('https://unpkg.com/@tehshrike/[email protected]'), ]).then(async ([{
    default: Turndown
}, {
    default: Readability
}]) => {

  /* Optional vault name */
  const vault = "Brain";

  /* Optional folder name such as "Clippings/" */

kepano

javascript: Promise.all([import('https://unpkg.com/[email protected]?module'), import('https://unpkg.com/@tehshrike/[email protected]'), ]).then(async ([{
    default: Turndown
}, {
    default: Readability
}]) => {

  /* Optional vault name */
  const vault = "";

  /* Optional folder name such as "Clippings/" */

JohnSundell

// A fun little game written in SwiftUI
// Copyright (c) John Sundell 2020, MIT license.
// This is a hacky implementation written just for fun.
// It's only verified to work on iPhones in portrait mode.

import SwiftUI

final class GameController: ObservableObject {
    @Published var plane = GameObject.plane()
    @Published private(set) var clouds = [GameObject]()

danielmartin

If you work on a Swift project that follows the Model-View-ViewModel (MVVM) architecture or similar, you may want to jump to counterpart in Xcode from your view to your model, and then to your view model. (ie. by using Ctrl+Cmd+Up and Ctrl+Cmd+Down).

You can do this in recent versions of Xcode by setting a configuration default.

From a terminal, just type this command and press Enter:

defaults write com.apple.dt.Xcode IDEAdditionalCounterpartSuffixes -array-add "ViewModel" "View"

keith

• Compiler flag: -enforce-exclusivity=<value>
• Build setting: SWIFT_ENFORCE_EXCLUSIVE_ACCESS

Xcode 10.1 & Swift 4.2

• Compiler default for non optimized builds if you pass no argument is the same as if you passed checked
• Compiler default for optimized builds if you pass no argument is the same as if you passed unchecked

Configuration	Compiler Flag Value	Build Setting Description	Build Setting Value	Notes

kastiglione

extension UIView {
    /// Example: call someView.nudge(0, 30)
    func nudge(_ dx: CGFloat, _ dy: CGFloat) {
        self.frame = self.frame.offsetBy(dx: dx, dy: dy)
        CATransaction.flush()
    }
}

extension UIView {
    /// Example: po UIView.root