Claude Code 5.
To get the most out of the new 5 series of Claude models, you need to upgrade your Claude Code harness. Here's how.
Welcome to another AI by Aakash. I follow the AI news so you don’t have to.
Thariq Shihipar is on the core team for Claude Code, and he recently shared a fascinating insight about the latest 5 series of models (Sonnet, Opus, and Fable).
The team deleted 80% of Claude Code's system prompt for Opus 5…. and it performed better.
So how do you set up your Claude Code optimally with the new Claude 5 models? That's today's deep dive.
But first, a word from our sponsor + the week’s AI news.
In Partnership with
Zapier SDK: I Had Claude Code Build a Link Auditor
I’ve never found a good way to catch the stale links in my old newsletter. Until now. This week I built a link auditor using Claude Code and Zapier SDK.
Here’s one of my recent runs through Cursor terminal. From 126 links across 7 posts, 2 were webinar registration links (that returned a 502) while 3 were redirected somewhere else. All this got stored in a Notion database through the Zapier SDK.
There was no OAuth flow or token handling to write as I had already connected those accounts to my Zapier account. The same interface covers the 9,000+ apps that Zapier connects to.
It’s in open beta currently, free, and the team is actively looking for feedback.
This Week’s AI News
The Week’s Top News: Google Rightly Moves the Chairs
Google’s Gemini models are god awful. And their harness engineering is pathetic.
Try any vibe based evals on tough tasks like the graphs we discussed last week. Gemini has no idea how to handle such a prompt and fails miserably. Gemini can’t even access YouTube or Maps data.
Google has had the talent, the data, and the resources. Yet its AI products, frankly, are terrible.
Both Claude, with Claude Code, and ChatGPT, with ChatGPT Work and Codex, are miles ahead. Occasionally throughout the past few years, OpenAI has been behind Anthropic. But it quickly catches up.
Meanwhile, Gemini barely ever releases anything. It’s gotten to 900M WAU merely through default placement and distribution. The last time Google had a top anything was Nano Banana 2, but that was quickly beat by ChatGPT Image Gen 2.
So it’s “good riddance” to hear that the supposedly “genius” Jeff Dean and Demis Hassabis have finally been moved out of their leadership positions. Google is trying to spin Demis’ move as a ‘step up,’ and word is Jeff left on his own, but any outside observer can clearly see they needed a leadership shake-up at the top.
Sergey Brin is taking over direct oversight of the Gemini models, and it’s the right call. Google clearly needs a good dose of “founder mode” to right the ship.
Here’s the AI product strategy I recommend to Sergey:
Immediately connect Google data to Gemini
Actually start releasing things quickly, at an AI pace
Make sure your models are competitive with the frontier
Stop shipping so many random products in labs that are disconnected
All of that is easier said than done. But if anyone has the resources to do it, it’s Google. I’ll check back in a few months, to see if Google has done any of this.
The Other News That Mattered
Unlike Google, Meta keeps releasing stuff and improving its standing in the AI race. Its model, Muse Spark 1.2 scored only a little behind Opus 5 on Terminal-Bench 2.1. And it’s also released Muse Code, its competitor to Claude Code.
Nvidia open-sourced Alpamayo 2 Super, a free 32B-parameter autonomous-vehicle reasoning model. It’s no wonder Uber abandoned their own training effort. They instead plan to use Nvidia’s models, and committed to 100,000 Nvidia-platform Level 4 vehicles starting 2027.
Scientists used AI to design 16 new viruses that can replicate inside cells. The biosecurity threats from AI continue to increase.
AI just read a stranger’s mind through their skull. Without any implants, it got roughly 45% of the meaning right on the first try. AI brain interfaces are coming.
Feature Updates
Wispr Flow’s Notetaker now transcribes meetings and labels speakers by their real name pulled from your calendar.
Claude Code sessions can now send messages to one another. Instead of having to copy paste responses between sessions, merely instruct them to talk to one another.
Bolt.new released a new template library of high quality apps.
Higgsfield has added Seedance 2.5, the SOTA video model.
Fundraising
Sapiom raised $35M to help you tackle rising AI token costs with agents.
Tools
Helena launched a self-improving AI marketer, running SEO, paid ads, and social content on autopilot. It rewrites the pieces that underperform.
Arcads launched Mark, an autonomous ad agent that takes a website URL, scrapes it for brand context, and generates ad creative and AI UGC video.
Not Diamond Code released a model router for long-horizon coding agents.
Superblocks 3.0 is a way for employees to securely vibe code enterprise software.
Deep Dive
Claude Code 5.
The instructions you wrote for last year’s model are now the thing holding this year’s model back.
If anything, the people carrying the most dead weight are the power users, like readers of this newsletter who have implemented elaborate operating systems with memory.
More setup means more of it quietly going stale.
I’ve tested everything Anthropic has said about the new 5 series models, including this awesome talk from creator Boris Cherny:
Today I’m sharing what you need to know:
The first principles
The 3 transformations to make
The skill that does it all for you
1. The first principles
It’s worth having a first principles understanding of why any of this matters.
For the most part, the rules in your CLAUDE.md, your skills, your graphs…
They’re all patches for mistakes older, dumber models used to make.
But the model gets smarter with every release. So the question really is: what patches can I get rid of with the new 5 series of models?
2. The 3 transformations to make
So can you just go and delete 80% of your system prompt? Not exactly.
Transformation 1 - Rebuild your customizations from the ground up
Claude Code has a safe mode that disables customizations.
This is a great way to baseline behavior.
Run your most common task in safe mode and compare it to what you’d get with everything loaded (without safe mode).
Here, for instance, I tasked the one-page PRD writer:
Here you can see, the safe mode PRD writer actually had a smarter recognition of the existing PRD.
So, in this case, start with the safe mode version and then add the customizations you need to be back in.
Other times, the customizations output will be better. In those cases, anything the raw model got right on its own is an instruction to delete.
Transformation 2 - Lighten your CLAUDE.md into skills
Most people’s CLAUDE.md is flooding with junk context which is stale from limitations of the older models.
All of it gets read after you give it a goal and that is the huge mistake.
run: /doctor
The checkup will find actions that give the model less irrelevant context, giving you a clearer place to maintain each workflow.
You can then move the information in CLAUDE.md out of there and into specific skills.
Transformation 3 - Define the outcome, not the steps
Most of us write prompts defining the procedure. With the 5 series of models, it’s better to define the task, guardrails, and completion criteria, then give the model room to decide how to proceed.
For instance I ran these two design prompts head to head - one procedural, one outcome based:
In the end, I judged the output focused on the outcome as better:
And this happened for everything I tested. With the 5 series of models, you can focus more on the outcome for all types of tasks.
3. The skill that does it all for you
Steal my skill here that will run a graph to do all three transformations for you:
Just run /update-to-cc-5 and it’ll handle the work for you.
And don’t forget to remove the skill when you’re done to avoid skill bloat!
Final Words
We keep adding to our AI customizations. Hopefully this was your sign to do the occasional subtraction step.
Implement the changes, and reply with your feedback! I read every reply.
P.S. Want my AI tool stack? Join my bundle. Want my job search coaching? Apply to my cohort. This is shaping up to be the last one. It starts in 7 days.
“Claude Code sessions can now send messages to one another. Instead of having to copy paste responses between sessions, merely instruct them to talk to one another.”
This makes me so happy! I am so appreciative of you helping me keep on top of the big and little things.
Truly, unique curation of what’s what is so great!