Field Log on Sentimark

Mindful by the River

Tue, 12 May 2026 00:00:00 +0000

A Note Before You Begin

Just past the berm at the end of our street, the Feather River runs south toward the valley. Most days it is quiet: green, slow, half-hidden by cottonwoods. In dry years it pulls back to a thread. In wet ones, after the Sierra snows let go, it pushes against the levee and reminds the town it is there.

The berm does not stop the river. It lets us live close to it.

Route of the Postman

Sat, 09 May 2026 00:00:00 +0000

This is the kind of trip that looks ordinary if you flatten it into logistics.

Redwood City to Corning. Corning to Eugene. A few days with family. The Oregon coast if the weather cooperates. Then the long road back through the valley, picking up the dogs and getting home before dinner.

That is the map version.

The feeling version is stranger and better. It is me getting ready to play postman across California and Oregon with Jelyn, Rosemary, Echo, Cashmere, and the dogs holding the line at the Corning ranch. It is a vacation, yes, but also a delivery run: people delivered to people, pets delivered to safe places, tired adults delivered out of routine for a few days.

Monetizing a Defect

Wed, 06 May 2026 00:00:00 +0000

Forgive me for a moment while I rant.

I’m a solo founder running a pre-revenue AI infrastructure company. This week I burned $100 in three hours on Claude Code “extra usage” doing routine work. I want to walk through what happened, because the pricing structure that produced that bill is not an accident, and the pattern is showing up across the industry.

For context, I was running Claude Code on a Max plan with extra usage enabled, working through architectural changes across a moderate-sized codebase. I had Opus 4.7 selected with the 1 Million token (1M) context variant. Three hours and roughly $100 later, I shut it down.

When Big Boy Came Through Marysville

Thu, 09 Apr 2026 00:00:00 +0000

There are machines you understand by reading about them, and there are machines that make reading feel beside the point.

Big Boy is the second kind.

Union Pacific brought Big Boy No. 4014 through Marysville on April 9, 2026, during its America 250 coast-to-coast steam tour. The public schedule had the stop at the 7th Street crossing from 3:30 to 3:45 p.m.¹ That is the sort of sentence a calendar understands. It does not capture the feeling of standing there with Jelyn, Esmeralda, and Blake while something enormous and alive-sounding moved into town.

Hard Negation

Fri, 13 Feb 2026 00:00:00 +0000

I did not set out to build a negation dataset because models could not understand the word not.

For the most part, frontier LLMs had solved the obvious version of that problem. Give them a clean sentence, ask whether the negated form changes the meaning, and they usually behave. The public datasets around negation reflected that world: useful historically, but brittle, narrow, and a little too easy to memorize.

The failure I cared about was harder.

The Magic of AMQ

Sat, 18 Oct 2025 00:00:00 +0000

There is a class of infrastructure problem where the obvious question is already too expensive.

Is this IP hot?

Has this tenant crossed a boundary?

Does this key belong to the set of things we should treat differently right now?

At small scale, you ask the question directly. You look in a database, call a cache, increment a counter, wait on a network hop, and move on with your day. At meaningful scale, that little moment becomes a tax on everything. The rate limiter becomes the thing being rate limited. The system built to protect your product becomes another dependency your product has to survive.