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Refining a model-as-judge evaluator in Apple's Evaluations framework

Two Refinements That Sharpen a Model-as-Judge Evaluator

Two refinements to the NeighborhoodCoherence judge from part two: pass the metric name straight to ModelJudgeEvaluator to drop the ScoreDimension boilerplate, and shape what the judge actually reads with evaluationTarget and reference.

August 19, 2026 · 7 min · Walid Sassi
When code can't judge quality: model-as-judge evaluators in Swift

When Code Can't Judge Quality: Model-as-Judge Evaluators in Apple's Evaluations Framework

Code-based evaluators can only measure what code can measure. This companion article goes deep on ModelJudgeEvaluator: choosing a scoring scale, writing scoring levels that actually work, and wiring a model-as-judge into the TripPlanner evaluation from part one.

July 26, 2026 · 7 min · Walid Sassi
Apple's Evaluations framework: testing non-deterministic Foundation Models features

Testing the Untestable: A Deep Dive into Apple's Evaluations Framework

How to test generative, non-deterministic features with Apple’s Evaluations framework, the five steps of an evaluation, datasets and the Loader protocol, synthetic sample generation, evaluators and metrics, and the compiler gotchas hit along the way.

July 19, 2026 · 22 min · Walid Sassi
Claude Agents in Claude Code, the new agent view for multi-agent iOS workflows

Claude Agents: Multi-Agent iOS Workflows in Claude Code

A walkthrough of Anthropic’s new Claude Agents (agent view) inside Claude Code on iOS: how to run a Clean Architecture refactor agent and a unit-testing agent in parallel on isolated Git worktrees, with the full lifecycle and synchronisation pitfalls.

May 13, 2026 · 12 min · Walid Sassi
MLX Embedders, Text Embeddings on Apple Silicon with Swift

MLX Embedders in Swift: On-Device Text Embeddings for iOS

In Part 1 of this series, we built a minimal LLM inference pipeline on Apple Silicon using MLX Swift. In Part 2, we quantized a model from scratch and saw how 4-bit precision makes billion-parameter models tractable on a phone. This article introduces MLX Embedders, specifically the MLXEmbedders Swift library, and takes a different angle. Instead of generating text, we are going to encode meaning. A user types: “best hikes near a volcano.” A keyword search returns nothing useful. An embedding-based system returns exactly what they need, because it understands what the words mean, not just what they spell. That capability is what embeddings unlock, and it is the foundation of every serious AI feature in production today: semantic search, recommendation systems, RAG pipelines, and clustering. ...

April 24, 2026 · 19 min · Walid Sassi
MLX Swift, On-Device Large Language Models on Apple Silicon

MLX Swift: Enabling On-Device Large Language Models on Apple Silicon

Abstract The proliferation of large-scale neural language models has, until recently, been contingent upon access to remote computational infrastructure. The architectural characteristics of Apple Silicon, most notably its unified memory subsystem, present a substantive departure from this dependency. This article examines MLX Swift, a native Swift binding to Apple’s MLX machine learning framework, as a mechanism for deploying quantized Large Language Models (LLMs) directly on consumer Apple hardware. We characterize the layered architecture of the MLX ecosystem, contrast its design philosophy with that of Apple’s Foundation Models API, and present a reference implementation demonstrating the complete inference lifecycle: model acquisition, session initialization, and autoregressive text generation. The discussion is grounded in the computational properties of unified memory and their implications for on-device inference efficiency. ...

March 31, 2026 · 13 min · Walid Sassi

Getting Started with Claude Code for Xcode 26: Setup, Pricing & Monitoring Guide

The landscape of iOS development has dramatically shifted in 2025. With Apple’s introduction of Xcode 26 at WWDC 2025, which integrates ChatGPT and supports multiple AI models through API keys, and Anthropic’s release of Claude Code as a powerful command-line tool for agentic coding, developers now have unprecedented AI-powered development capabilities. ...

September 2, 2025 · 6 min · Walid Sassi

Understanding Swift's isolated Keyword: Parameters and Closures

Swift’s concurrency model introduces actors to provide safe, isolated access to mutable state. However, constantly using await when interacting with actors can create performance bottlenecks and reduce code readability. The isolated keyword offers an elegant solution by allowing synchronous access to actor state in specific contexts. ...

August 18, 2025 · 2 min · Walid Sassi

Integrating Claude API with Xcode 26 Beta 5: A Complete Guide

With the release of Xcode 26, developers now have exciting new possibilities for integrating AI capabilities directly into their development workflow. In this article, I’ll walk you through my experience integrating Claude’s API with Xcode 26 Beta 5, including the cost considerations and token system that you should be aware of. Getting Started: API Key Setup Step 1: Creating Your API Key The first step is to obtain your API key from the Anthropic Console: ...

August 14, 2025 · 2 min · Walid Sassi

Swift Actor Common Pitfall: Parameters Are NOT Protected!

class DownloadCounter { var count = 0 var lastDownload: Date? } actor DownloadManager { private var totalProcessed = 0 // ✅ Protected by actor func processDownload(_ counter: DownloadCounter) async { totalProcessed += 1 // ✅ Safe - actor's state // 💥 DANGER: counter is NOT protected! counter.count += 1 // ❌ Potential data race counter.lastDownload = Date() // ❌ Potential data race } } // Data race scenario func dangerousUsage() async { let counter = DownloadCounter() let manager = DownloadManager() // Thread 1 Task { await manager.processDownload(counter) } // Thread 2 - Concurrent access! Task { counter.count += 5 // 💥 DATA RACE with Thread 1 } } ✅ The Solution: sending to Transfer Ownership ...

August 11, 2025 · 1 min · Walid Sassi