DiegoVallejo

Diego Vallejo

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Analysis and reflections on technology, language, and thought

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26 articles

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Agent Evals Are the New Unit Tests — And Yours Are Flaky

Evals are the only thing standing between your agent and production, and most of them fail for reasons that have nothing to do with the agent. Here is how I stopped trusting a green run.

aitestingengineeringagents

SPEI Is About to Eat Mexico's Card Payments

How Mexico’s real-time interbank payment rail went from back-office plumbing to the default way millions pay — and why cards are now the underdog.

bankingengineeringarchitecturestrategy

MCPs Are the New Glue Code

The Model Context Protocol buys you a socket, not a clean integration. Here is how the promise of plug-and-play agent tooling quietly becomes the same old adapter problem.

aimcpintegrationarchitectureglue code

The Half-Life of a Good Abstraction

Why every abstraction that saves you once will eventually cost you, and how to know when to rewrite it.

software engineeringarchitectureabstractioncomplexity

Decoding the Artificial Analysis Coding Agent Index v1.1

Version 1.1 replaces SWE-Bench-Pro-Hard-AA with DeepSWE and averages pass@1 across three complementary benchmarks. Here is what each component measures, what the headline score hides, and how to use it when choosing a coding agent.

aiengineeringbenchmarks

Anatomía de un fracaso: análisis del rediseño y colapso de infraestructura de BBVA México

El rediseño de la app de BBVA México y las caídas continuas en 2025 y 2026 exponen qué sucede cuando la experiencia de usuario y la estabilidad del backend desacoplan sus prioridades: una lección sobre arquitectura financiera.

bankinguxinfraestructuraingenieríaresiliencia

AI Devs Now: What Tools Are Trending Right Now (August 2026)

August 2026 developer radar: stateless MCP, universal memory layers, open-source meta-harnesses, and the new model tier reshaping agentic coding.

aiengineering

The Anatomy of an AI GPU: From SIMT to Silicon Photonics

A layer-by-layer tour of modern accelerator design: SMs vs CUs, tensor cores, reticle limits, prefill vs decode, the 1000W power wall, HBM4, and why the compiler is the final boss.

hardwareaiarchitectureengineering

The Polaris Council: A Live Demo of Layered Agent Debate

An interactive policy-debate demo built on the POLARIS multi-agent framework: five biased agents, four layers, and a quality gate that decides when the answer is good enough.

aiMulti-Agent Systemstypescriptpolarisdemo

I Turned Off Copilot for a Week: Field Notes

Seven days without AI autocomplete. What got slower, what got sharper, and what I turned back on when the week was over.

aiessayengineering

Context Windows Are Not Memory: Engineering Recall for AI Agents

Why stuffing the prompt is a losing strategy, and how to design a tiered memory architecture with deterministic eviction and retrieval budgets.

aiarchitectureengineeringtypescript

AI Devs Now: What Tools Are Trending Right Now (July 2026)

An empirical analysis of the mid-2026 development stack: from AI-native IDEs and autonomous orchestration to agentic DevSecOps.

aiengineering

Deconstructing the Hive Mind: The Multi-Agent Topology of POLARIS

How Policy Optimization via Layered Agent Recursive Inference Search enforces determinism through agent isolation.

aiMulti-Agent SystemsTypeScriptarchitecture

I’ve Been Using Devin/Windsurf All Week: It’s the Synergy, Not the Automation

Reflections after orchestrating a dozen minor side projects. Here is what we missed in the tutorial: the paradigm shift from reactive assistance to proactive predictive engineering.

aiessayengineering

Desbloqueando el Valor Real de la IA: Protocolos de Ingeniería para un ROI Medible y Escalable

Superando el 80%+ de fracaso en proyectos de IA: Una arquitectura estructural para transformar la experimentación corporativa en rendimiento empírico, contable y defendible en el P&L.

aiengineeringstrategy

AI Devs Now: What Tools Are Trending Right Now (June 2026)

An empirical analysis of the mid-2026 development stack: from AI-native IDEs and autonomous orchestration to agentic DevSecOps.

aiengineering

La Ansiedad como Simulación Estocástica: Formalización del Control y el Rendimiento

Sustituyendo la rumiación psicológica por un modelo matemático: Teoría de Prospectos, entropía de Shannon y optimización no lineal para entender la incertidumbre.

essay

Hardware as Memory, Software as Files: The Axioms of System Architecture

Eradicating opaque abstractions by aligning software design with empirical system realities.

architecture

Getting Up to Date with React

A chronological tour of every major React feature — from JSX to Server Components — with live demos you can play with.

reactfrontend

The TypeScript Wizard Cheat Sheet: Beyond `any`

A reference for conditional types, inference, branded primitives, and template literal magic. Strict mode only.

typescript

Deterministic Event Pipelines for AI Agents

Why `while(true)` is technical debt, and how to implement O(1) event dispatching for scalable agent systems in Node.js.

aiarchitectureengineeringtypescript

Stop Building Form Monsters: A Battle-Tested Guide to Sequential UX

Ditch the monolithic form for a state-driven, accessible multi-step architecture that scales.

accessibilityux

Deterministic Mutation: Implementing Transactional State in React

Moving beyond naive useState hooks to handle complex data flows and atomic dirty-state validation.

reactfrontend

Prompt Engineering Is Deprecated: The Era of Systemic Constraint

Why natural language persuasion fails in production AI pipelines and how to implement strict logical boundaries via schema enforcement and logit bias.

ai

Neuro-Glial AI Architecture

Architectural Redefinition: From Synaptocentric to Hybrid Models.

aiarchitecture

Accessibility Is Not a Feature: It Is the Foundation of the Web

Why A11y compliance must be a development axiom, not a post-production patch.

accessibilityfrontend