Independent builder

David Belschak.

Fascinated by AI. I build my own tools.

Discipline

Business & software

Self-taught builder

Shipped

2 apps in daily use + 2 open-source skills

Not prototypes

Next start line

0days

Lisbon Marathon · 10.10.26

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Manifesto

I build the tools I wish existed, then use them every day until they earn their place.

03  Open source

Read the source. Vet the code.

Two Claude Code skills, shipped from my own workflow. They are two halves of one discipline: your agent should read the real source, and you should know what code you run before you run it.

belschak / web-research-cascade

Claude Code skill

Stops your agent from silently reading the wrong source.

Four fetch stages, from plain WebFetch to your own logged-in browser. The rule sits above the ladder: when a source blocks, escalate the fetch. Never swap the source for a weaker one just because that one loads.

$ git clone --depth=1 https://github.com/belschak/web-research-cascade.git ~/.claude/skills/web-research-cascade
Repository  The story: your agent gets a 403 

Related: repo-audit vets the code before you run it.

belschak / repo-audit

Claude Code skill

Reads third-party code for red flags before you install it.

Six read-only phases: maintainer reputation, install hooks, obfuscation, exfiltration patterns, prompt injection in agent-facing files. Every run ends in a verdict, and every verdict comes with evidence.

$ claude "audit this repo before I install it"
verdict: SAFE-WITH-CONDITIONS · no license, pin the commit
Repository 

Related: web-research-cascade reads the source your agent quotes.

04  Selected work

Built for one user: me.

Two apps, both in daily use: one for studying, one for marathon training.

01 · Study tool

Recall

Sign-in

Spaced-repetition flashcards, generated automatically from lecture PDFs and reviewed on an FSRS schedule.

2026 · recall.belschak.dev

Open project 

02 · Training tool

Marathon Dashboard

Private

Live training telemetry for the 2026 Lisbon Marathon: runs, pace trends and race readiness in one view.

  Private tool · live behind a passcode

2026 · marathon.belschak.dev

Open project 

The workshop

I don't just use agents. I run them with discipline.

Every tool on this site is built with agents in the loop. Three standing rules decide what an agent reads, what gets installed, and what goes public. The rules are the craft.

38.7223° N · 9.1393° W

  • Rule 01
    what gets read

    Blocked sources escalate. They never get swapped.

    When a primary source blocks the fetch, the agent climbs a four-stage ladder that ends in my own browser. Quietly reading a weaker source instead is the one move that is off the table.

    ↳ Shipped as web-research-cascade

  • Rule 02
    what gets in

    Third-party code gets read before it runs.

    Maintainer history, install hooks, what leaves the machine: a six-phase read-only audit ends in a verdict with evidence. No verdict, no install.

    ↳ Shipped as repo-audit

  • Rule 03
    what goes out

    Nothing goes public without passing the gate.

    Secrets, licenses, claims that cannot be backed: one final pass stands between the working tree and the internet, and it has veto power. Deadlines included.

    ↳ Runs before every release

Notes from the workbench 

06  Writing

Notes from the workbench.

Your agent gets a 403 and silently downgrades its sources

Bot-blocking quietly pushes research agents from primary sources to whatever happens to load; a small escalation cascade fixes that.

Read the post 

All writing 

07  About

Maastricht

Lisboa

38.7223° N
9.1393° W

I studied International Business with a major in Finance in Maastricht, and in September 2026 I start my Master in Finance at Nova SBE in Lisbon. I always saw potential in AI, but since Claude Code took off in early 2026 it has become a genuine fascination I spend several hours on every day. This site is my portfolio of personal use cases: tools I built for my own life, published so others can use them or take ideas from them.