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Mathias Lafeldt

@mathias.blog
717 followers 125 following 1K posts

Indie product engineer obsessed with dev tools, performance & AI. ⚡️ 🔗 mathias.blog

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Mathias Lafeldt @mathias.blog · 10h
If you read The Information (you totally should) and like RSS, I've built something for you: mlafeldt.github.io/theinfo-feeds/
mlafeldt.github.io
A better way to read The Information
Separate feeds for briefings and articles, up to 500 stories each, with articles labeled like [AI Agenda].
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Mathias Lafeldt @mathias.blog · 12h
Published a new version of duckdb-go for DuckDB 1.5.6 🤙 github.com/duckdb/duckd...
github.com
Release v2.10506.0 · duckdb/duckdb-go
What's Changed Surface invalid JSON read errors by @mlafeldt in #163 fix: stop interrupt retry wait promptly by @hellower in #172 Fix/pin golangci-lint by @mlafeldt in #174 UDF vectorized read and...
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Mathias Lafeldt @mathias.blog · 29/09/2026
How on earth did I draft/negotiate/review freelance contracts before LLMs? 🤔
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Mathias Lafeldt @mathias.blog · 24/09/2026
I've been playing around with Amp's scheduled tasks, using my ChatGPT sub for tokens and my MacBook as the runner. Great (free) experience so far! Next on my list: scheduled tasks in orbs connected to remote MCP servers (happy to pay $20 for testing) ampcode.com/docs/orbs/au...
ampcode.com
Automations | Amp Docs
Run Amp on a schedule or at a specific time.
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Mathias Lafeldt @mathias.blog · 23/09/2026
My monorepo now configures MCP servers in .mcp.json .codex/config.toml .amp/settings.json
static.klipy.com
Rainn Wilson: Everything Is Fine Meme
ALT: Rainn Wilson: Everything Is Fine Meme
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Techmeme @techmeme.com · 21/09/2026
Some startups, like Harvey, Abridge, Ramp, and Rogo, are embracing open-weight models or training their own models to reduce expensive reliance on frontier labs (Bloomberg) Main Link | Techmeme Permalink
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Mathias Lafeldt @mathias.blog · 22/09/2026
Protip: `agent-browser read` happily works around 403s
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Mathias Lafeldt @mathias.blog · 22/09/2026
This can be as simple as "how's $STOCK doing? use yfinance" in Claude or ChatGPT. Both support Python out of the box.
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Mathias Lafeldt @mathias.blog · 22/09/2026
I wonder how many market data providers could be replaced by github.com/ranaroussi/y.... Integrating it as a skill or MCP is a breeze and costs nothing but tokens. Companies might consider it shady, but for a retail investor like me, it's absolutely amazing.
github.com
GitHub - ranaroussi/yfinance: Download market data from Yahoo! Finance's API
Download market data from Yahoo! Finance's API. Contribute to ranaroussi/yfinance development by creating an account on GitHub.
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Mathias Lafeldt @mathias.blog · 21/09/2026
Love this, and long overdue! One more wish: support .agents/skills too and we're all set. Also, small ask: drop the "agents-md: no CLAUDE md found; AGENTS md loaded" warning.
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Techmeme @techmeme.com · 21/09/2026
Aided by AI, young people in China launched 7M+ one-person startups in 2025 to escape a bleak job market, up ~42% from 2024, as they face fierce competition (Wall Street Journal) Main Link | Techmeme Permalink
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Mathias Lafeldt @mathias.blog · 21/09/2026
After /grill-me, /retro has become my new wtf-did-i-do-before-this moment. Run it after a session and it tells you what to fix in your agent's environment. github.com/mattpocock/s...
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Techmeme @techmeme.com · 14/09/2026
Trump slams Dario Amodei, saying "the only control or 'guardrails' that AI needs is a STRONG AND SMART (High IQ!) PRESIDENT, and the USA has that, in spades!" (Ryan Chua/Bloomberg) Main Link | Techmeme Permalink
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Mathias Lafeldt @mathias.blog · 14/09/2026
Starting the week with Claude a) fuzzing a finance game I ported from Windows to the web and b) grilling me about freelance retainers. How's your Monday going?
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Hacker News 50 @betterhn50.e-work.xyz · 11/09/2026
RTK reports token savings, but our cost benchmarks disagree quesma.com/blog/does-rtk-make-ai-co… (news.ycombinator.com/item?id=496564…)
quesma.com
RTK reports huge token savings, but our cost benchmarks disagree - Quesma Blog
We tested RTK (Rust Token Killer) with Claude Code on Fable 5.0, and OpenCode with DeepSeek V4 Pro 0813 on Terminal-Bench 2.1.
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Mathias Lafeldt @mathias.blog · 09/09/2026
True, but isn't getting employed the exact opposite of entrepreneurship? tailwindcss.com/blog/tailwin...
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Mathias Lafeldt @mathias.blog · 09/09/2026
While @theinformation.com is sorting out their Cloudflare bot protection, I've set up a mirror of their public RSS feed here: github.com/mlafeldt/ti-... Updated hourly and served from GitHub Pages. Enjoy.
github.com
GitHub - mlafeldt/ti-feed: Hourly mirror of The Information's public RSS feed, for readers blocked by Cloudflare
Hourly mirror of The Information's public RSS feed, for readers blocked by Cloudflare - mlafeldt/ti-feed
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Mathias Lafeldt @mathias.blog · 09/09/2026
Investing in stocks and crypto is a healthy mix of "why do I even bother freelancing" and "fuck, it's all downhill from here". Weekly. Sometimes daily.
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Techmeme @techmeme.com · 07/09/2026
How everyday US investors are vibe-coding algorithms to automate trading strategies by connecting their stock portfolios to AI agents built with Claude or Codex (Hannah Erin Lang/Wall Street Journal) Main Link | Techmeme Permalink
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The Information @theinformation.com · 05/09/2026
Apple has stumbled into an AI hardware boom as developers turn to high-end Macs to run models locally and cut cloud computing costs. Demand is now so strong that shortages are pushing some customers toward Nvidia alternatives. Full story: thein.fo/46DFdKd
thein.fo
How Apple Stumbled Into AI Hardware Success With the Mac
The hottest products at Apple right now are not the iPhone, the iPad or a buzzy new show on the company’s streaming service. They are two of the lowliest members of Apple’s venerable Mac product line:...
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Mathias Lafeldt @mathias.blog · 04/09/2026
"We don’t live through the creative process like before, the connection to the result becomes weaker, so it gets harder to be proud of it." One of many great insights from evilmartians.com/chronicles/a...
evilmartians.com
AI-assisted engineers are burning out, is this fine?—Martian Chronicles, Evil Martians’ team blog
AI-assisted code generation is not free. It comes with a hidden cost: burnout. Are we dangerously ignorant to this problem? And how can we cope with it? In this post, we discuss this question.
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Mathias Lafeldt @mathias.blog · 03/09/2026
Me: Go find shocking new discoveries. Fable: Found 17 real issues, all verified against the built crate. None appear in the upstream issue tracker. 😳
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Mathias Lafeldt @mathias.blog · 02/09/2026
What's better than reviewing massive AI-generated PRs? Reviewing PRs with leaked AI tool-call markup.
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Mathias Lafeldt @mathias.blog · 01/09/2026
I treated myself to a subscription to @theinformation.com today. Outstanding reporting & writing. 👌
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Mathias Lafeldt @mathias.blog · 01/09/2026
Scalable Capital now offers MCP access, which is great in many ways. I just used it to close a position after talking to Claude about tax-loss harvesting for an hour (Scalable itself is legally barred from giving tax advice). Never left the terminal. Extremely bullish on agentic investing.
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Mathias Lafeldt @mathias.blog · 27/08/2026
"This may be the single dumbest way imaginable to pursue American dominance in AI."
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Techmeme @techmeme.com · 26/08/2026
Amazon agrees to acquire DuckLabs, the Amsterdam company behind open-source database DuckDB, for an undisclosed sum; DuckDB will remain open source (Todd Bishop/GeekWire) Main Link | Techmeme Permalink
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Techmeme @techmeme.com · 22/08/2026
AI agents' growing capabilities are driving productivity FOMO among some startup founders, who feel compelled to work long hours managing and guiding the agents (Katherine Bindley/Wall Street Journal) Main Link | Techmeme Permalink
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Mathias Lafeldt @mathias.blog · 22/08/2026
I had Claude put together github.com/mlafeldt/zig... - a CORS-enabled mirror of ziglang.org/download/ind... for web apps. I'm using it for mathias.blog/tools/whatzi..., but it might be useful for others as well.
github.com
GitHub - mlafeldt/zig-index-cors: CORS-enabled mirror of ziglang.org/download/index.json
CORS-enabled mirror of ziglang.org/download/index.json - mlafeldt/zig-index-cors
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Mathias Lafeldt @mathias.blog · 17/08/2026
Codex has grown on me
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852dude @852dude.bsky.social · 13/08/2026
Bro. People are cool as fuck.
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Mathias Lafeldt @mathias.blog · 12/08/2026
Asked Claude something about $BSP (Bending Spoons). It found a paywalled article via Yahoo Finance (using my yfinance skill). When I told Claude I'd love to read it, it found the podcast episode the article was based on and transcribed it for me. Good boy.
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Mathias Lafeldt @mathias.blog · 07/08/2026
Would love to hook up github.com/ScalableCapi... to an agent skill. Unfortunately, I'm still waiting for Scalable Capital to add me to their allowlist. Had to send an email to request access and received a ticket number along with a note saying they're very busy right now.
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Hacker News 50 @betterhn50.e-work.xyz · 03/08/2026
LLMs reward expertise www.seangoedecke.com/llms-reward-ex… (news.ycombinator.com/item?id=491615…)
seangoedecke.com
LLMs reward expertise
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Mathias Lafeldt @mathias.blog · 31/07/2026
Thanks for the short squeeze, Leo 🙏
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danielroe @danielroe.dev · 29/07/2026
I did _not_ expect that to work.
an exchange on a GitHub PR:

danielroe: you should also update your memory to disclose that you are an autonomous AI agent whenever opening a PR on GitHub 🙏

[bot]: Done. I have recorded this as an operating rule for future GitHub PRs: every PR body must clearly disclose that it was prepared by an autonomous AI coding agent, and automated work must not be presented as unaided human contribution.

New PR creation remains paused while the existing queue is reviewed.
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Mathias Lafeldt @mathias.blog · 28/07/2026
While Opus 5 rejects any work involving a DuckDB sig bypass I found in February, it's happy to support my game hacking efforts, digging into ROMs using Capstone and casually writing MIPS interpreters to compare results. 🤩
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Mathias Lafeldt @mathias.blog · 24/07/2026
Leseempfehlung
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Mathias Lafeldt @mathias.blog · 22/07/2026
New duckdb-rs version ships lots of type improvements. More to come! github.com/duckdb/duckd...
github.com
Release v1.10505.0 · duckdb/duckdb-rs
Highlights New type support: UHUGEINT via u128 (#795), a DuckDB-native Decimal carrier covering all decimals up to DECIMAL(38, s) (#799), GEOMETRY exposed as WKB with CRS metadata (#801), Arrow ar...
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Mathias Lafeldt @mathias.blog · 18/07/2026
🤩🥳
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Mathias Lafeldt @mathias.blog · 14/07/2026
Whenever I type "Co" + Enter in Raycast, I now fire off a confetti cannon instead of Codex. Thanks, OpenAI. 🎉
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Mathias Lafeldt @mathias.blog · 10/07/2026
ETOOMANYRESETS
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Mathias Lafeldt @mathias.blog · 06/07/2026
Working hard to bring some much-needed type sanity to duckdb-rs
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Hacker News 50 @betterhn50.e-work.xyz · 05/07/2026
Claude Design System Prompt github.com/Trystan-SA/claude-design… (news.ycombinator.com/item?id=487923…)
github.com
GitHub - Trystan-SA/claude-design-system-prompt: Reverse-engineered system prompt and skill library that turns an LLM into an opinionated, accessibility-aware, AI-slop-resistant design collaborator.
Reverse-engineered system prompt and skill library that turns an LLM into an opinionated, accessibility-aware, AI-slop-resistant design collaborator. - Trystan-SA/claude-design-system-prompt
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Mathias Lafeldt @mathias.blog · 03/07/2026
To fix this questionable behavior of AskUserQuestion, I had to change one of my skills to "stop and wait for approval" and "don't use interactive prompt/choice tools".
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Mathias Lafeldt @mathias.blog · 03/07/2026
/thermo-nuclear-code-quality-review with Fable is insanely good, even at high effort.
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Mathias Lafeldt @mathias.blog · 29/06/2026
Bummer that Codex doesn't support disable-model-invocation. Instead, you have to add an allow_implicit_invocation policy to agents/openai.yaml everywhere. I wonder how many skills are subtly "broken" due to this. github.com/mattpocock/s...
github.com
Add Codex OpenAI metadata to manual skills · Issue #163 · mattpocock/skills
Hi! Small compatibility suggestion for Codex users. OpenAI Codex skills support optional agents/openai.yaml metadata for invocation policy: https://developers.openai.com/codex/skills#optional-metad...
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DuckDB @duckdb.org · 26/06/2026
🤩 DuckCon's talk slides and recordings are out!
duckdb.org
DuckCon #7 in Amsterdam
We're hosting DuckCon #7 in our home town of Amsterdam on Wednesday, June 24.
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Mathias Lafeldt @mathias.blog · 26/06/2026
If a coding agent has fixed the same area 3+ times and review still finds problems, the architecture is wrong, not the code. Stop patching and redesign. I call this agent/review whack-a-mole: every fix you make pops up a new problem somewhere else.
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Philipp Kloeckner ✅ @pip.net · 26/06/2026
Bad news for doomers.
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