Prompt Optimizer

Overview

Prompt Optimizer is a native macOS utility that turns rough text into a well-engineered prompt without leaving the app you're in. Select text anywhere, press ⌥Space, and a floating panel returns two rewrites generated against a chosen profile: Concise, Creative, Technical, or custom. Accepted rewrites feed an on-device learning engine that replays them as few-shot examples on the next call, so suggestions track your style over time. A Hub window manages a local library of saved prompts, parameterized templates, and settings. Everything runs locally: the only network traffic is one encrypted call to the configured model provider, with the API key held in the Keychain and no telemetry.

Highlights

• Global-hotkey capture with a dual clipboard + Accessibility-API path for reliable text grabs across any app
• On-device learning engine records accepted rewrites and replays them as few-shot examples, so it personalizes without anything leaving the machine
• Profile system encodes seven rewriting techniques (chain-of-thought, analogical, and others) as swappable system prompts
• Promptfoo eval harness scores 60 core prompts × 7 profiles on an LLM-judge rubric, cross-validated across OpenAI, Anthropic, and Google
• Quantified same-family judge bias (99% self-pass vs 60-81% cross-model), a concrete prompt-engineering finding, not a wrapper

Stack & tools

• Swift
• SwiftUI
• Core Data
• Keychain
• Accessibility API
• OpenAI API
• Promptfoo
• XCTest