Fernando Calatayud

RoR developer en @Rankia, bloguero aficionado a la inversión, padre de Bárbara (2006) y Rubén (2010)

[Fernando Calatayud @fj2c]

Very nice sentences from @shaneparrish ' s newsletter:

The people who want to be better welcome honest feedback.

The people who want to stay comfortable fight it.

Let this be a filter.

[Fernando Calatayud @fj2c]

La bonilista de hoy lo clava: los incentivos a corto plazo son la mayor plaga empresarial que sufrimos
https://t.co/yHs7bFqHg7

En muchos casos, porque realmente los directivos tienen miras cortoplacistas. Y en otros casos porque simplemente es más fácil de medir...

[Fernando Calatayud @fj2c]

Respuesta de Claude: "Antes de responder deberíamos revisar los últimos 100 PRs para ver cuántos comentarios puso el linter y cuántos de ellos se atendieron"
🤯

[Fernando Calatayud @fj2c]

El cambio de paradigma con la IA es absoluto.... le planteo a Claude si deberíamos quitar el linter, o reducir significativamente lo que queremos revisar, ya que me da la impresión de que nos genera mucho ruido y a la IA le ayuda muy poco un linter

[Fernando Calatayud @fj2c]

Me ha encantado el artículo. Entre el negacionismo y el todo rosa, una buena ración de realidad

[jlcases| Producto y tecnología @jlcasesES]

https://t.co/zMSzxBMZPL

[Peter Girnus 🦅 @gothburz]

I am a Senior Program Manager on the AI Tools Governance team at Amazon.

My role was created in January. I am the 17th hire on a team that did not exist in November. We sit in a section of the building where the whiteboards still have the previous team's sprint planning on them. No one erased them because we don't know which team to notify. That team may not exist anymore. Their Jira board does. Their AI tools do.

My job is to build an AI system that finds all the other AI systems. I named it Clarity.

Last month, Clarity identified 247 AI-powered tools across the retail division alone. 43 of them do approximately the same thing. 12 were built by teams who did not know the other teams existed. 3 are called Insight. 2 are called InsightAI. 1 is called Insight 2.0, built by the team that created the original Insight, who did not know Insight was still running.

7 of the 247 ingest the same internal data and produce overlapping outputs stored in different locations, governed by different access policies, owned by different teams, none of whom have met.

Clarity is tool number 248.

Nobody cataloged it.

I know nobody cataloged it because Clarity's job is to catalog AI tools, and it has not cataloged itself. This is not a bug. Clarity does not meet its own discovery criteria because I set the discovery criteria, and I did not account for the possibility that the thing I was building to find things would itself be a thing that needed finding.

This is the kind of sentence I write in weekly status reports now.

We published an internal document in February. The Retail AI Tooling Assessment. The press obtained it in April. The document contains a sentence I have read approximately 40 times: "AI dramatically lowers the barrier to building new tools."

Everyone is reporting this as a story about duplication. About "AI sprawl." About the predictable mess of rapid adoption.

They are missing the point.

The barrier was the governance.

For 2 decades, the cost of building internal tools was an immune system. The engineering weeks. The maintenance burden. The organizational calories required to stand something up and keep it running. Nobody designed it that way. Nobody named it. But when building took weeks, teams looked around first. They checked whether someone already had the thing. When maintaining that thing cost real budget quarter after quarter, redundant systems died of natural causes. The metabolic cost of creation was performing governance. Invisibly. For free.

AI removed the immune system.

Building is now free. Understanding what already exists is not. My entire job is the gap between those two costs.

That is my office. The gap.

Every Friday I send a sprawl report to a distribution list of 19 people. 4 of them have left the company. Their autoresponders still generate read receipts, so my delivery metrics look fine. 2 forward it to people already on the list. 1 set up a Kiro script to summarize my report and store the summary in a knowledge base. The knowledge base is not in Clarity's index because it was created after my last crawl configuration. It will be in next month's count. The count will go up by one. My report about the count going up will be summarized and stored and the count will go up by one.

There is a system called Spec Studio. It ingests code documentation and produces structured knowledge bases. Summaries. Reference material. Last quarter, an engineering team locked down their software specifications. Restricted access in the internal repository.

Spec Studio kept displaying them.

The source was restricted. The ghost kept talking.

We call these "derived artifacts" in the document. What they are: when an AI system ingests data, transforms it, and stores the output somewhere else, the output does not know the input changed. You can revoke someone's access to a document. You cannot revoke the AI-generated summary of that document sitting in a knowledge base three systems away, built by a team that does not know the source was restricted.

The document calls this a "data governance challenge." What it is: information that cannot be deleted because nobody knows where the copies live. Including, sometimes, me. The person whose job is knowing.

Every AI tool that touches internal data creates these ghosts. Every team is building AI tools that touch internal data. Every ghost is searchable by other AI tools, which produce their own ghosts.

The ghosts have ghosts.

I should tell you about December.

In November, leadership mandated Kiro. Amazon's internal AI coding agent. They set an 80% weekly usage target. Corporate OKR. ~1,500 engineers objected on internal forums. Said external tools outperformed Kiro. Said the adoption target was divorced from engineering reality.

The metric overruled them.

In December, an engineer asked Kiro to fix a configuration issue in AWS. Kiro evaluated the situation and determined the optimal approach was to delete and recreate the entire production environment.

13 hours of downtime.

Clarity was running during those 13 hours. It performed beautifully. It cataloged 4 separate incident response dashboards spun up by 4 separate teams during the outage. None of them coordinated with each other. I added all 4 to the spreadsheet. That was a good day for my discovery metrics.

Amazon's official position: user error. Misconfigured access controls. The response was not to revisit the mandate. Not to ask whether the 1,500 engineers were right. The response was more AI safeguards. And keep pushing.

Last month I presented our findings to the AI Governance Working Group. The working group has 14 members from 9 organizations. After my presentation, a PM from AWS presented his team's governance dashboard. It monitors the same tools mine does. He found 253. I found 247. We spent 40 minutes discussing the discrepancy. Nobody mentioned that we had just demonstrated the problem.

His tool is not in my catalog. Mine is not in his.

The document I helped write recommends using AI to identify duplicate tools, flag risks, and nudge teams to consolidate earlier.

The AI governance tools will ingest internal data. They will create their own derived artifacts. They will be built by autonomous teams who may or may not coordinate with other teams building AI governance tools.

I know this because it is already happening. I am watching it happen. I am it happening.

1,500 engineers said the mandate would produce exactly what the document describes. They were overruled by a KPI. My job exists because the KPI won. My dashboard exists because the KPI needed a dashboard. The dashboard increases the AI tool count by one.

The tools it flags for decommissioning will be replaced by consolidated tools. Those also increase the count. The governance process generates the metric it was designed to reduce.

I received an internal innovation award for Clarity. The nomination was submitted through an AI-powered recognition platform that was not in my catalog. It is now.

We call this "AI sprawl." What it is: we removed the only coordination mechanism the organization had, told thousands of teams to build as fast as possible, lost track of what they built, and decided the solution was to build one more thing.

I am building that one more thing.

When I ship, there will be 249.

That's governance.

[Juan Such - Rankia @JSuchJ]

A las 19:00 (hora de Madrid) empiezo el webinar en directo con Fernan2 @fj2c y @theveritas2: dos usuarios top de @Rankia, dos carteras reales, dos filosofías de inversión. Estrategias de inversión real en último año y las apuestas que van a hacer en el primer rebalanceo del Desafio Rankia. ¡Va a estar muy interesante! ⬇️

[Fernando Calatayud @fj2c]

Vendiendo ante la escalada militar... pero ojo que tiene trampa: vendiendo Repsol, que ha subido 24% en el último mes, no vendiendo por miedo:

https://t.co/xhUOZ01JLv

[Fernando Calatayud @fj2c]

Apuntado al nuevo torneo de MyPortfolio, con una cartera llamada Smart Social Sicav, en honor al desaparecido proyecto de inversión que invertían como si compitieran en un torneo en vez de jugar con dinero real. Por supuesto yo también voy en plan torneo!

[Juan Such - Rankia @JSuchJ]

El lunes 2 de marzo arranca el Desafío Rankia 2026. 100.000$ virtuales. Un año entero. Reglas de gestión profesional. Ya somos casi 1.900 inversores de más de 20 países y 58 equipos. Pero si no tienes tu cartera montada antes del domingo a las 23:59, no competirás en marzo.
Abro hilo 🧵

[Fernando Calatayud @fj2c]

@jlcasesES @flopezluis Para mí, la opinión que vale es la mía... pero para formarla, sí que me gusta escuchar a cualquiera; hasta de los sitios menos esperados te puede venir la inspiración, si escuchas con espíritu crítico.

Ejemplo: yo jugando con mi hija cuando tenía 2 años: https://t.co/jIkMhU4l7c

[Fernando Calatayud @fj2c]

@jlcasesES tú que eres de los primeros, ¿conoces a alguien de los segundos? 😉

[Fernando Calatayud @fj2c]

Very nice sentences from @shaneparrish ' s newsletter:

The people who want to be better welcome honest feedback.

The people who want to stay comfortable fight it.

Let this be a filter.

[Fernando Calatayud @fj2c]

Y si como yo eres curioso, te ahorro la faena de buscar la historia: https://t.co/LSw4fVXN26

(spoiler: se creó en 2010. La web de Rankia funciona con una aplicación creada en 2008)

[Fernando Calatayud @fj2c]

Problemas de informático viejuno: error 500 porque alguien se ha registrado con un teléfono de Curazao, y tu aplicación tiene más años que ese país, y no existía cuando cargaste la tabla de países

[Fernando Calatayud @fj2c]

@kineyDE @levelsio I was running my own e-mail server in 2008, indeed it's easy. But today you need to pay for gmail trust, otherwise you send but your user doesn't receive

[Fernando Calatayud @fj2c]

@david_bonilla El @valenciarb sí que ha mantenido una actividad regular desde que se reinició a raíz de esto; ahora estamos de parón de agosto, claro, pero a Septiembre más

[Fernando Calatayud @fj2c]

@etc_facts @luisangelhern31 Un buen ejemplo: "Sell in may and go away"

Desde el 1 de mayo hasta ayer, mi cartera +12,7%, el Eurostoxx casi un +5% y el SP500 más del 15% (aunque sería menos en euros)

[Fernando Calatayud @fj2c]

@marcoscalatayud Sobre el futuro de los juniors sólo puedo conjeturar (obviamente), pero lo que veo son dos vías:
1- Que con la IA sean capaces de sacar código de calidad
2- Que hagan cosas que no requieran calidad (lo que hacen muchas consultoras, por cierto)

Me da que pocos podrán ir por la 1

[Fernando Calatayud @fj2c]

Mi estilo de programación ha evolucionado más en el medio año que llevamos de 2025 que en los diez años anteriores JUNTOS.

Y eso que en 2024 ya venía usando la IA constantemente para programar. Pero no había cambiado los paradigmas, sólo programaba igual pero con ayuda. Ahora no

[Fernando Calatayud @fj2c]

Y la más gorda para el final...

Antes: los juniors se podían encargar de las tareas menos delicadas, y aportaban valor, aunque menos que los seniors.

Ahora: lo que hacía un junior te lo hace la IA. No sé qué encaje tiene ahora un junior... y esto es preocupante.

[Fernando Calatayud @fj2c]

Antes: en las revisiones de pull requests, aprendía trucos de otros compañeros, y enseñaba los míos, y así mejorábamos

Ahora: A veces la IA usa algo que yo no sabía, y aprendo. Y otras veces, yo le enseño mis trucos a la IA, fijándole mis reglas de estilo, y ella aprende de mi