stop running everything on opus

Claude Sonnet 5 landed on June 30, the first proper Sonnet upgrade since 4.6, and it's a big leap.

It's now landing right near Opus on a lot of real work. only about 2% behind Opus 4.8 on computer use and agentic coding (agentic just means the AI going off and doing multi-step tasks on its own - instead of just answering a question), and actually ahead on knowledge work.

The one real gap is a coding benchmark called SWE-bench Pro, where it sits at 63% to Opus's 69%. that's just a test of how many real coding tasks each one solves solo, so on your toughest builds Opus still wins.

Alongside it, Anthropic put out an official chart plotting cost against performance across the different effort levels, and it's turned "which model should I use?" into a real case-by-case call.

For some tasks Opus 4.8 is both cheaper AND better. for others Sonnet 5 is the smarter pick.

These two charts show it at a glance: Sonnet 5 is the better buy down at low/medium effort, and Opus 4.8 pulls ahead once you're paying for high effort.

Where Sonnet 5 really shines is the routine, scheduled, low-effort stuff.

a daily brief, clearing an email inbox, the jobs that still need doing properly but don't need an ultra-capable model like Opus behind them.

Anthropic's lineup now has four tiers:

IMPORTANT PLS READ: The one rule worth remembering: Sonnet 5 is a bargain at low and medium effort. but push it to high, xhigh or max and its cost climbs right up onto Opus 4.8's, and at that point Opus matches or beats it.

OpenAI previewed a new three-model family on June 26, called GPT-5.6. three flavours: Sol (the flagship), Terra (the balanced middle), and Luna (the cheap, fast one).

Terra gives you roughly GPT-5.5-level performance at about half the cost.

GPT-5.5 is already excellent at coding, following instructions and business tasks, so "same quality, half the price" is the bit that actually lands.

Rough pricing per million tokens: Sol $5 / $30, Terra $2.50 / $15, Luna $1 / $6.

But you and I can't use them yet. at the US government's request, access is limited to about 20 approved partners, handed out customer by customer, with wider availability promised "in the coming weeks."

Why so locked down? frontier models are now capable enough to carry real cyber-security risk, and (tied up with the whole Fable 5 saga) that's made these releases political.

It's a shame they're this restricted, I get why though. hopefully we all get access in due time.

Quick one, since I covered the ban itself a couple of weeks ago.

Fable 5 is usable again. the export ban got lifted and it returned globally on July 1, after 19 days offline.

But read the small print. it's only included for up to 50% of your weekly usage, and only on your plan until July 7. that's basically a week.

After July 7 it goes API-cost only, roughly double the price of Opus 4.8, so it stops being "free" on your subscription.

So if you've got any big builds you've been sitting on, now's the time. crank through as much as you can with Fable 5 while it's still on your plan.

(In case you missed it, here's where I covered fable 5.)

The subscription-audit skill: full transparency on what I am actually paying for.

I built a skill called subscription audit.

it goes through my email inbox and my bank statements, pulls the receipts for every new subscription, price change and cancellation, and builds it all out into a Notion database, so I've got complete transparency on every subscription I'm paying for.

I've set it to run on a schedule every Friday, so it just keeps itself current without me touching it.

Two skills that now run my email marketing end to end.

All my time and attention this week went on the course launch, and two skills carried the entire email side of it.

First I built an AI with Remy email copywriting skill that captures my actual voice, how I write marketing emails.

then an email formatting skill that connects to Resend (where I send my marketing emails from).

Here's the loop for every email I sent this week: I run the copywriting skill and voice-note my thoughts, tweak the draft myself (rewrite a few bits, add an intro), then run the formatting skill and it drops the email straight into Resend, styled in my house look.

I do one final once-over, hit send, and it automatically logs the email in my Notion Email Calendar with the content and marks it as sent.

Two skills, and the whole email side basically runs itself now.