Spec-Driven Development: the SDD → RPI → Harness loop
Why writing the spec before the code isn't ceremony — it's the only way to parallelize AI without rewriting three times.
Jair Nunes
Software & AI Systems Architect
I'm Jair Nunes — a software architect with fifteen years building enterprise e-commerce and retail systems, and for the last few years putting AI agent systems into production. Not demos, not conference slides — systems that survive contact with reality: a multilingual GenAI pipeline that ran in production for two years across three continents, handling specialized-domain hallucination, loop detection inside the agent loop, and at-least-once persistence on the steps you can't undo.
The method I build around is Service as Software — spec-driven development, harness engineering, and multi-agent pipelines with human-in-the-loop gates and real observability. Wiring a prompt is the easy part; the work is making it hold under load, cost, and failure. This site is the long-form home for that — the short version lives on LinkedIn, the code on GitHub. To talk: contato@jairnunes.com.
Good software disappears. The rest is marketing.
Featured
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Context Lattice: coordinating multiple AI squads without losing the thread
How lat.md files become the canonical source of context across parallel agents, and why that solves the telephone-game problem in AI squads.
Recent writing
Projects
- skeleton-agent — Reference implementation of the Service-as-Software method — a provider-agnostic agent scaffold. Swap the model engine without touching the domain layer.
- Remarge — Multi-tenant SaaS for abandoned-cart recovery in e-commerce. WhatsApp + AI, idempotent, built to tolerate an unstable messaging API.
What I work on
Fifteen years across enterprise e-commerce and retail. Where I go deep:
- Agent systems in production — multi-agent pipelines, human-in-the-loop gates, cost and failure observability.
- Enterprise e-commerce platforms — catalogs with millions of SKUs, incremental indexing, search.
- Card-present payments & self-checkout — pinpads, offline queues on SQLite, idempotency under retry.
- Payments & checkout — PIX, card, recovery flows that survive a flaky PSP.
- Resilience under peak — systems that can't go down on the busiest day of the year.
- Legacy migration — strangler-fig, evolution scripts, zero-downtime cutovers.
Where I write
- LinkedIn — short, practical notes on engineering and shipping AI into production.
- GitHub — open-source work and code.
- Substack — Infraestrutura Invisível — occasional long-form essays, in Portuguese.
Get in touch
Email: contato@jairnunes.com. LinkedIn for a quick message (/in/jairnunes). GitHub issues for technical discussion (@jairnunes). I don't run a contact form — that's the filter.