Open to consulting, collaboration, and roles

Dependable AI systems, built on the harness, not the model.

This headline started as a wordy prompt. Cutting the filler took it from about 22 tokens to 13. Same idea, applied to whole systems, is what I do.

I’m Iggy Mwangi, an AI systems architect in Dallas–Fort Worth with 25+ years of shipping software at Apple, Sam’s Club, AT&T, and Contran. I call my approach Compound Engineering: put the effort into the harness (context, checks, and fixed workflows) instead of waiting for a better model, so every system gets more reliable and the next one ships faster.

Below: free tools that run in your browser, field guides, and open-source code. No account needed.

Now VynixAI · Nubla AI Earlier Apple · Sam’s Club · Contran · AT&T Since 1998

A simulated agent run. Each step follows a fixed path, and nothing ships until it passes a check.

What brings you here?

Try it: make a prompt clearer

Paste a prompt, or pick an example. You’ll get a score, a list of what’s missing, a version with the filler words removed, and a rewrite with clear sections. It’s a small version of Prompt Matrix Evaluator, and everything happens in your browser.

Tightened

Hi! Write a welcome email for our new customers. Mention the free trial and stuff, and keep it friendly and good.

About 47 tokens down to about 29, roughly 38% fewer.

Tools

Each tool is a single page you can use right away. Every card says where your text goes, so you can choose the ones that fit your privacy needs.

New to this? Four words you’ll see a lot
Prompt
The instructions and text you give an AI model, like a message in a chat.
Token
The unit models read and bill by. A token is roughly three-quarters of an English word, so fewer tokens usually means faster and cheaper replies.
Context window
How much text a model can consider at once. When a conversation outgrows it, older parts get dropped or ignored.
Agent
An AI model that works in steps: it uses tools, checks the results, and tries again if something fails, instead of answering once.

What the labels mean

  • Stays on your device Your text is processed in this browser tab and not sent anywhere.
  • Remembers your work Saves to this browser’s storage so it’s there next visit. Clear your site data to remove it.
  • Needs your API key Sends your prompt to OpenAI or Anthropic using a key you supply.
  • Sends text to a server Your text goes to a server I run, which passes it to a hosted model.

Improve a prompt

Build, reuse, and compare prompts

Plan and design AI systems

Read

Field guides I keep current on GitHub, essays from this site, and seventeen subject sites. Subscribe to new essays (Atom feed).

Field guides

Essays

Code

Open-source code on GitHub. Free to read, use, and adapt under each repo’s license.

Work with me

Open to consulting, collaboration, and roles.

How I build: every change follows a fixed path and passes a check before it ships.

What I help teams with

  • Making AI agents dependable. Fixed workflows and structured outputs, so an agent follows a path you can audit instead of improvising.
  • Keeping costs and wait times down. Tighter prompts and smarter context so the important instructions stay in view and bills stay predictable.
  • Shipping safely. Checks on tool calls and code changes before they land, with isolated execution and clear policies.

How I work: Compound Engineering

Harness over model. Most AI failures I’m called in for aren’t model problems; they’re missing context, missing checks, and agents left to improvise. I fix the harness around the model, and each fix becomes a reusable part, so the second system costs a fraction of the first.

Experience

2025 – present

VynixAI · Senior Solutions Architect, AI & Cloud Infrastructure

AI-driven, cloud-native, and edge platforms for real-time retail and enterprise workloads: RAG pipelines, scalable inference, and agent automation.

2024 – present

Nubla AI · Cloud Architect and Machine Learning Engineer

ML systems and cloud architectures across AWS, Azure, and GCP, focused on LLM integration, retrieval, and dependable ML pipelines.

2022 – 2023

Apple · Cloud Architect and Engineer

Cloud modernization across AWS and Apple’s internal platforms: replaced lift-and-shift workloads with serverless and container designs, moved pipelines to event-driven architectures, and led FinOps work.

2017 – 2021

Sam’s Club · Principal Software Engineer, Cloud and Machine Learning

Cloud ML for forecasting, computer vision, and real-time analytics, plus retail line-of-business apps on Azure, iOS, and Android at retail scale.

2011 – 2017

Contran · Mobile, Web, and Systems Architect

Unified fragmented mobile, web, and backend systems across iOS, Android, AWS, and GCP for long-running operational workflows.

Earlier, 1998 – 2011: AT&T, Verizon, Cingular, EDS, ADP, IBM Innovation Center, BP-Amoco, Williams Communications, and others. B.Sc. Computer Science, University of Minnesota.

Results

38%
fewer hallucinations after re-architecting our RAG pipeline VynixAI
42%
more reliable multi-tool routing, by treating tools as state transitions VynixAI
27%
lower spend from cost-aware LLM routing, with no drop in quality VynixAI
70%
less debugging time with OpenTelemetry reasoning-trace observability VynixAI
22%
lower LLM latency by reworking tokenization paths Nubla AI
35%
shorter training time by reorganizing data across S3, BigQuery, and ADLS Nubla AI
30%+
lower cloud spend year over year through right-sizing, auto-scaling, and FinOps Apple
~30%
lower compute cost by moving pipelines to event-driven designs Apple

Baselines and methods aren’t published here. The work falls under confidentiality agreements with my employers. I’m glad to discuss the details under NDA.