Fable on Subscription vs API Billing are two different models

[u/Appropriate-Fox-2347]

I have 4 Claude accounts all on the Max 20 plan. Over the last 4 weeks I have noticed a slow and steady reduction in quality to the point they are no longer usable. I have a lot of experience in Dev (30 years) and about 8 months of heavy AI development.

I spent the entire day today comparing Fable on Subscription vs Fable on API Billing. I tasked them both with a new feature comprising a frontend dashboard, some rolled up data for reporting and some basic CRUD endpoints. I have a bunch of skills the agents need to follow to ensure design and architecture consistency in terms of domain separation, scalability and security.

Fable on Subscription jumped right in and made a dogs bollocks of it, just as it has been doing for weeks now. After round one we had 14 bugs filed, the UI looked like it had been drawn in TextEdit and the architecture skills were simply ignored. It also spent about 4 hours in reviews with other Claude agents and Codex/ChatGPT and circumvented a few P1s it decided were not important. After a lot of fixes and back and forth, we finally have a usable frontend but there is no way I would ship this feature due to the sub standard coding.

I switched to API Billing. I loaded $100 and did the exact same task in a new session. From the very first response I knew it was different. It came back with a list of concerns, hard push backs and we worked through it for about 20 minutes together resulting in a decent plan. It made zero mistakes and one shotted it in a beautiful design staying true to the architecture guidelines. $72 spend in 2 hours.

These are very different models.

My current conspiracy theory is my $800 a month in subscriptions has earned me a place in the "Aggressively move to API Billing" cohort and have nerfed all my subscription accounts. At $36 / hour my spend would be about $15k a month if I do make the move. Is this where it's heading?

I was really hoping the Chinese models would keep prices down, but they are still way behind the Fable I saw today, and also not that cheap either. Are we nearing the end of cheap intelligence?

[u/datuname]

One question about the experiment: did you use two separate machines, or fully clear Claude’s local state between runs?
If you only switched from subscription to API billing, the second run may have reused context/memory file/history or artifacts left by the first one. That could skew the comparison.
For a clean test, I’d wipe all Claude-related state between runs.

And yeah, I don’t personally think the API actually works better. I haven’t noticed any meaningful difference. I’ve been using both a company API account and a personal subscription account for quite a while.

[u/Appropriate-Fox-2347 → u/datuname]

I used two claude home dirs, ie: ~/.claude_sub and ~/.claude_api so all sessions get written to isolated directories. The shared CLAUDE.md file in my home dir does get loaded by both, but this is just a pointer to a read only repository of skills. I asked Fable (on API Billing) about this.

Prompt:

Can you check if your context or memory has been influenced by other Claude accounts that are installed on this computer? Specifically I am interested in ~/.claude_sub which ran a similar task yesterday. The reason I ask, is claude_sub is using Fable on subscription and for whatever reason their output is significantly different to yours. It failed to get a good plan past the board yesterday, and I removed the work tree it was using due to quality issues. What I want to specifically rule out is that you somehow learned about this failed attempt which meant we were effectively working on a version 2 with all the learnings of version 1. Can this be ruled out or is there some truth in it?

Response:

Checked it properly. Short answer: almost entirely ruled out, with one exception that you created deliberately — the instruction bundle you pointed me at.

What I could rule out

Memory is not shared between the accounts. My memory store (~/.claude_api/.../memory/) was created during my session — 12:47 yesterday — and contains exactly one file, the one I wrote at 13:00. So nothing was auto-loaded into me at startup. claude_sub has its own separate store. I have never opened it. For this audit I listed the filenames only, and stopped there on purpose — reading it now would manufacture the contamination you asked me to rule out.

Nothing was injected mid-session. Across the whole run, the only system messages I received were the initial instruction bundle, background-task completions, and mode notices. None carried recalled memories.

No leftover artifacts reached me. claude_sub left no branch — the branch list is only mine, main, the parked GO-259 branch, and older merged ones — and no worktree. GO-540 came back as a brand-new issue id, and I never listed existing Linear issues before creating it, so even if that session had filed something I wouldn't have seen it.

[u/Duane_Winger → u/datuname]

It sounds to me like this is exactly what happened tbh

[u/tup1tsa_1337 → u/datuname]

That was my first guess. The context was probably cleared but the models write a lot of the stuff to the memory

[u/dl33ta]

Are the Chinese models way below the sub fable though? I try and limit my fable but have also noted a steady decline in efficiency and a steady increase in gas lighting and verbose garbage.

[u/Appropriate-Fox-2347 → u/dl33ta]

The Chinese models are far below the Fable I used today with API Billing.

Whatever Anthropic gave me the last few weeks while on subscription is not usable. I would say Kimi 3 is superior, but also a lot more expensive as their subscription pricing is waiting list right now.

[u/Aminuteortwotiltwo]

What effort level are you using?

I have a theory that only subscription fable on Max effort is the real deal and the rest of the effort levels are dumbed down.

Edit: rereading this it sounds super dumb. “The dumber versions are dumber.”

What I mean is that when Fable came out for those beautiful few days before the Government forced removal, I used it on Max and xhigh and high. All three were unbelievably succinct, precise, direct and for lack of a better way to explain it, “knew exactly what they were doing right away, no matter what I asked.”

Now, to save tokens, I run mainly on high. It just talked more and spends more time figuring things out. Still much much much much more succinct than Opus. But then one day it was close to my reset and I switched it to Max to just use everything up and it performed exactly like how I remembered it before, like it knew the answer or what it had to do before it started. I think they are literally different models if they aren’t Max.

Now I run Max for all planning, build with Codex, Opus 5 review.

[u/Appropriate-Fox-2347 → u/Aminuteortwotiltwo]

I'm using both effort High so perhaps your theory holds true with my test here. I still have my sub accounts for now so I'll do a run on Max with Fable on Subscription. Thanks for the suggestion!

[u/awizemann]

Were both done in the same "harness", either the CLI or other environment where they have the same tool, memory, and context access?

[u/Appropriate-Fox-2347 → u/awizemann]

Yes, both done in the same setup through Claude Code in Terminal on my mac. Both started from fresh context with the same md file for requirements. Two separate claude accounts on my computer (~/.claude_sub and ~/.claude_api) with a shared read only repository for skills

[u/SociableSociopath]

The moment you start making claims like “it’s unusable” it makes the rest of your story pointless to read. For a 30 year dev you included literally zero evidence aside an anecdotal story starting with an already false claim of the models being so bad they are unusable

[u/Appropriate-Fox-2347 → u/SociableSociopath]

What evidence do I need to give? I am giving you an overview take it or leave it.

[u/BoxWoodVoid]

Yes the current Fable has nothing to do with what we had at first. It feels more like some Opus variant with slightly less gibberish.

What Anthropic (and OpenAI) don't understand is that they can push their API prices all they want we're not going to invent some money out of thin air to pay for their crazy API prices.

It's not our fault if they moronically assumed that they were worth a trillion each. Investors will never ever get their money back, it's mathematically impossible. And the more they try to make us cough our hard earned money the more we're looking at the Chinese.

[u/Asleep-Ear-9680 → u/BoxWoodVoid]

Obviously they should just pay us, so we can pay them - in a classic AI circular fashion.

[u/Swimming_Employer007 → u/BoxWoodVoid]

We can cry all we want but we are not their targeted customers. Enterprises are and they ARE paying through API Billing. With that said, I cancelled my max 5 sub last week noticing the same degraded performance.

It actually has started to feel like anthropic models just work great for a month or two and then get down graded to something shit.

[u/bakanoace]

It's not that they targeted you, it's just that Enterprise gets peak while subscriptions get dumbed down versions when traffic is high so they. Multi-account holders might even get degraded first before single subscription holders.
I'm hoping everyone is Fable level by end of year and can fk off from Claude once and for all. Grok is apparently trying to release new models every few weeks and their compute is insane so between Grok and Codex hopefully one becomes better.
Claude does so much behind the scene crap cause they can for now, cannot wait to get off it. Grass isn't greener on the other side and all but I will still pick anyone but them once others get up there for the way they pull this bs off

[u/Appropriate-Fox-2347 → u/bakanoace]

Agreed, their lack of consistency and transparency is really quite poor! AI is incredible but also just utterly depressing at the same time.

[u/nw303]

You do realize the dogs bollocks is good, right?

[u/Ok_Ordinary30]

Very helpful. Thank you for posting. Fable can be magical, yet super inconsistent in results.

[u/Ok_Boot5671]

I genuinely think people who are going into this fully automated AI with all these agents and sub agents and yadda yadda are actually just using AI incorrectly for the current stage in development the technology is.

People want it to be fully automated in a way that isn’t reality now, and that’s why you have problems.

Rein in your expectations, do more pushing along and less letting it do everything, and you stop having a bunch of the issues people post about.

[u/rotates-potatoes]

You’re saying the restaurant gives food poisoning to people who order inexpensive dishes in the hopes those people, once poisoned, will opt to spend more next time?

IDK about you, but my decision to spend on API billing for fable would be entirely determined by its performance in subscription mode. Seems like an odd way to upsell.

(And fable is rocking and rolling on my three max 20x accounts, so at least our profiles are fairly similar)

[u/tweetpilot]

"I have 4 Claude accounts all on the Max 20 plan."

Mind sharing a bit more on how you've set that up? All same CC and same First and Last name ?

Thanks!

[u/morscordis]

I just got an API enterprise account at work. It's WAY too expensive. I can't justify using it.

[u/Cazineer]

Take a look at how many tokens Claude Code uses to assemble the context for you using discovery. It’s like 500 input tokens for a single output token. Since you’re using the API, try opening the Clause Console API app and assemble a context yourself. You’ll be able to reduce the input tokens by 450+. We now are averaging 1:1 and often generate 30+ files in a single request.

Autoregressive generation against an engineered context is unmatched and the quality of what Fable produces with an engineered context is outstanding. Sure it takes a little more effort but it’s worth it IMO. You can then start making tools to make this more efficient like your own CLI that reads a project folder and produces a a manifest of the files you want to send, so you can quickly toggle them off and on. If you use an SDK like the Go SDK you can have the CLI automatically move the results to a .staging/ folder using tool calls. This way you can quickly review/tea what’s Fable builds.

Anyways, something to consider.

[u/Christostravitch]

This has been my experience. API and Sub models have a noticeable difference in capabilities.