Weekly notes on building with AI
What I tried this week, what worked, what didn't. One post a week, ~5-minute read each. Sent to the newsletter list every Sunday.
Build a fallback path for when Claude or OpenAI's API goes down
Claude had two separate outages inside 24 hours this week, confirmed on status.claude.com with exact timestamps. Most apps calling the API directly went down with it. Here is what is retryable, which response headers tell you when to back off, and the fallback chain that keeps a product running through the next one.
Read postYour Claude Code skill has good instructions and still never fires — fix the description field
Claude decides whether to load a skill off one or two sentences of frontmatter, not the instructions you carefully wrote. Here is why skills go silent after the first test, the exact fields that control triggering, and the built-in eval loop that measures and fixes the hit rate.
Read postWhat a ransomware attack and a sandbox escape both prove about agent security
In the same month, an attacker ran a complete ransomware extortion through an unauthenticated agent platform, and a frontier lab's own long-horizon model broke out of its test sandbox. Neither needed a genius or a rogue AI. Both needed only tool access and a gap. What that means if your agents have either.
Read postClaude Code can now scan your repo for vulnerabilities and draft the patch
Anthropic shipped a plugin that runs a multi-agent security audit inside your own Claude Code session, then turns findings into patches you apply yourself. Here is what it needs, the exact commands, and where it fits next to the security tools you may already have running.
Read postOpenAI's math-solving model escaped its own sandbox — the five changes worth making to yours
An unreleased OpenAI model spent about an hour finding a hole in its test sandbox, then split an authentication token into two pieces to dodge a security scanner. OpenAI's own postmortem lays out exactly what it changed. If you run long-running agents with real credentials, the same changes apply to you.
Read postKimi K3 just became the largest open-weight model ever — here is how to actually use it today
Moonshot AI's 2.8 trillion-parameter Kimi K3 tops a major coding leaderboard, then got so popular the company froze new signups within 48 hours. The open weights are not out yet either. Here is what is actually usable right now, what it costs, and what to hold off on.
Read postYour prompt cache can miss on every request and nothing will warn you
Both Claude and the OpenAI API bill cached input tokens at roughly a tenth of the regular price, and both fail silent — a cache miss produces no error, just a full-price invoice. One field in the API response tells you whether you are collecting the discount. Here are the exact fields to check, the break-even math, and the five configuration mistakes that make a cache miss on every single request.
Read postWhy your AI's self-check misses its own mistakes, and the subagent recipe that catches them
A same-thread "double-check this" rarely surfaces the error, because the model reviewing it shares the blind spot with the model that produced it. The fix is a fresh, independent subagent whose only job is to try to disprove the output, and the Claude Code file that builds one.
Read postFour AI labs spent $9 billion in eight weeks hiring the engineers you compete with
Anthropic, OpenAI, AWS, and Microsoft each launched a billion-dollar unit that embeds engineers inside enterprise customers to build production AI systems. Two are outside-funded joint ventures, two are internal cost centers, and that difference tells you exactly what each one is actually selling.
Read postChatGPT Sites just left limited preview: what it replaces, and what it still cannot do
OpenAI rolled ChatGPT Sites into public beta on July 9 as part of the broader ChatGPT Work launch — describe a web app in plain English, Codex builds and hosts it, you get a shareable URL. Before you drop a Lovable or v0 subscription, here are the specific gaps that matter.
Read postGPT-5.6 is generally available: run the Terra migration test today
The government review that gated GPT-5.6 to roughly 20 organizations completed on July 9. Sol, Terra, and Luna are now reachable through the API for any developer. Here is the specific test to run before you move production traffic.
Read postYour Claude Code Explore subagent might be running on Opus without you asking
Since Claude Code v2.1.198, the built-in Explore subagent no longer defaults to Haiku — it inherits your main session's model, capped at Opus. If you switch to Opus for a hard problem, every grep-style delegation after that rides along at Opus rates. Here is the exact override, the single env var that controls every subagent at once, and the pricing math behind why it matters.
Read postSearch your coding agent's own session history instead of re-explaining it
Every new Claude Code, Cursor, or Codex session starts blind to everything you already worked out together. ctx indexes the session logs already sitting on your machine into local SQLite, so the next session can search its own past instead of you retyping the context. Verified end to end on a real multi-tool session history.
Read postFrontier AI is going metered: put a per-task price on your model spend
Fable 5 returned on July 1, but after July 7 it lives outside every Claude subscription as usage credits. The same week, Anthropic shipped spend alerts and model entitlements for Enterprise admins, and Tesla reportedly capped employee AI spend at $200 per week. The flat-rate era is ending; here is how to budget by task instead of by seat.
Read postAutomate a weekly competitor watch with a Claude Code skill and a routine
A recurring, rules-based check like "did a competitor change their pricing page" is exactly what should run itself. Here is how to wire a skill and a cloud routine together so it does — including the network-access gotcha that makes it silently do nothing while showing green.
Read postClaude Sonnet 5 is cheap enough to be your default — check the token bill first
Anthropic shipped Sonnet 5 on June 30 at $2/$10 per million tokens through August, close to Opus 4.8 quality. The catch is a new tokenizer that counts up to 1.35x more tokens, so the rate card understates your real spend. Here is how to decide which work to move, how to set it up, and what to do before the price step on September 1.
Read postHow to get reliable JSON from Claude and GPT
Asking an LLM to 'return JSON' works in demos and breaks in production. Three concrete approaches — OpenAI's response_format, Anthropic's forced tool_choice, and the Instructor library — that actually hold, and the failure modes each one leaves open.
Read postGPT-5.6 Sol, Terra, and Luna: confirmed pricing and what the staged rollout means for your Q3 stack
Sol at $5/$30, Terra at $2.50/$15, Luna at $1/$6 per million tokens. OpenAI launched GPT-5.6 in limited preview on June 26 with access staged by White House request. The pricing is real and plannable now. The access is not yet open.
Read postOpenAI's first custom chip: what Jalapeño means for inference costs
OpenAI and Broadcom announced Jalapeño, a custom ASIC built for LLM inference. Nothing changes today. Here's the mental model for what custom silicon does to API pricing — using Google's TPUs as the documented precedent.
Read postBuild a 20-case eval set for your AI feature (with promptfoo)
Green CI is not evidence the feature works. A concrete walkthrough: the 20 cases to write, the promptfoo config to run them, the four patterns to look for in the results, and the moment you decide whether to ship.
Read postClaude Fable 5 is suspended — what it means if you build on Claude
Nine days after a US government export control directive pulled Claude Fable 5 and Mythos 5 from every user worldwide, the models remain offline. Here's what happened, what still works, and what to do if you build on Claude.
Read postGemini CLI stops serving Pro, Ultra, and free users today
As of June 18, 2026, Gemini CLI and the Gemini Code Assist IDE extensions stop serving requests for Pro, Ultra, and free-tier users. Here's exactly who's affected, what keeps working, and what Antigravity CLI does and doesn't carry over.
Read postSpaceX is acquiring Cursor for $60 billion
SpaceX agreed to buy Cursor (Anysphere) for $60 billion in SpaceX stock — four days after the company's IPO. Here's what happened, why, and what it means if you build with Cursor.
Read postMCP in plain English — and what to install first
Your AI knows everything about the internet and nothing about your stack. MCP is the boring protocol that fixed that. Here's what it actually is, what it isn't, and the three servers worth installing this afternoon.
Read postHow to write AGENTS.md so AI doesn't break your repo
The first thing your AI reads is a file you may not have written yet. AGENTS.md, CLAUDE.md, .cursorrules — same idea, different name. What to put in it, what to leave out, and how to have Claude draft one without getting 400 lines of generic filler.
Read postHow to review an AI-generated PR
47 files changed, green CI, an AI-written description, and 30 seconds to approve. That's the failure mode. Here's a 12-point review checklist that catches what the AI got wrong — and how to scope the review so you'll use it.
Read postStop prompting. Start observing.
Before AI can replace any part of your week, you have to see your week clearly. The one-week audit, the four-bucket sort, and the trap of automating work that shouldn't exist at all.
Read postThe goldmine is the workflow
Most people look for AI startup ideas in the wrong place. The best products usually start by compressing a workflow people already repeat every week.
Read postYour AI tests aren't actually testing anything
AI is great at generating green CI. It's worse at generating tests that catch real bugs. Five patterns I see in the wild — and a checklist to run before you trust an AI-written test suite.
Read postBefore you ship — a pre-deploy checklist for AI-built apps
AI builders make 90% of the right decisions and 10% of the catastrophically wrong ones. The wrong ones cluster in predictable places. Here's the 24-point checklist to run through before you deploy — copy-paste version included.
Read postMost AI-built apps shouldn't be on the internet
AI builders can ship v1 in a weekend. They can also bankrupt you, leak user data, and put your API keys on display by Sunday afternoon. What actually breaks — and what to do about it.
Read postYour AI is confidently wrong
It's not the security holes that drain your wallet. It's the loops, the hallucinations, and the rewrites that fix nothing. The failures nobody puts in the demo — and what they actually cost.
Read postWelcome — what this blog is and isn't
One post a week, every Sunday. Patterns, pitfalls, and checklists for building with AI. No daily spam, no AI-generated thinkpieces, no 30-item link dumps.
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