#152

Fable 5.1 breaks forced tool calls, 67 cents ties TRM, and Codex carries LibreOffice

Fable 5.1 kept Fable 5's $10/$50 price and returns a 400 for every forced tool call, on every account. A 75M transformer trained for 67 cents ties TRM on ARC-AGI-1.

Bump your model string to Fable 5.1 and the first forced tool call comes back a 400. Every account, from the day it shipped, no grace period. The stated reason: thinking is always on now, and forcing a call would skip it.

The sticker price didn’t move either. Input and output stay at $10 and $50 per million tokens. The advertised 25% saving is one line item: cache reads, $1.00 down to $0.25.

In today’s indie hacker news:

  • 🤖 Fable 5.1 ships three breaking changes
  • 🪙 A from-scratch transformer matched a lab’s score
  • 📦 Both AI desktop apps ship an office suite
  • 🧠 Stack: a 104GB model on a 48GB Mac

TOP STORIES

ANTHROPIC BREAKS THE FORCED TOOL CALL

🤖 Fable 5.1 and Mythos 5.1 land with three breaking changes

Cartoon builder balancing on a stack of books holds out an envelope stuffed with wrenches and screwdrivers as a giant wooden stamp slams an X across it

The story: Anthropic shipped both models yesterday. tool_choice of type any or tool now returns an invalid_request_error, on the Messages API and on token counting. The fix is {type:"auto"} with strict tool use or structured outputs behind it.

The details:

  • Thinking blocks now bind to their conversation. Change the system prompt, the tools or any earlier message and the call is rejected.
  • Enforced only for accounts created on or after August 31, per the docs.
  • ARC Prize scored 97.5% on ARC-AGI-1 and 90.0% on ARC-AGI-2, semi-private, max effort.
  • GodelNumbering: minus the five-day-old Terminal-Bench-Science score, it beats the cheaper Opus 5 by 1.5 to 3.5 points.

Why builders care: If you maintain a framework other people run with their own key, your own key is almost certainly on an older account. You will never see the error they get.

A 67-CENT MODEL TIED A SAMSUNG LAB

🪙 A 75M transformer trained from scratch hits 44% on the ARC-AGI-1 public eval

Cartoon builder sits cross-legged on one pan of a balance scale with a glowing coin, a graphics card and a small colored grid puzzle, holding level against a huge worried server rack on the other pan

The story: Mithil Vakde rented one RTX 5090 on vast.ai and trained an 8-layer transformer from random init. It matches the score TRM published on the same public eval. Two GPU-hours, 67 cents.

The details:

  • Strip the 3D RoPE or the per-task embeddings and his ablations fall to about 24%. The representation is what carried the score.
  • Self-scored on the public eval, on no ARC Prize leaderboard. He gets 7% on ARC-AGI-2.
  • HN’s title said “it beats many LLMs”. A third party submitted it, cutting “scores the same as TRM/HRM” from his subtitle. The chart plots zero LLMs.
  • The repo has 240 stars and hasn’t been pushed since April.

Why builders care: He was nine months into learning ML when he ran this. Whatever you shelved as too expensive to train, re-price it.

THE CHATGPT APP PACKS ITS OWN OFFICE

📦 The ChatGPT desktop app keeps a headless LibreOffice, and Claude’s local bundle is six times bigger

Cartoon builder knocked to the floor as a toppling tower of copiers, typewriters, scanners and filing cabinets erupts from a small open briefcase

The story: Simon Willison went digging in the ChatGPT desktop app, the one that used to ship as Codex. It vendors the whole toolchain: a headless LibreOffice dev build, Poppler, git, its own language runtimes. That’s 1.7GB. The document skills call those instead of yours.

The details:

  • native/ holds 771MB of it, and LibreOffice alone is 429.7MB. Node and Python add 887MB beside it.
  • No OpenAI changelog mentions it, and it may download on first run rather than ship in the installer. Nobody in 137 comments ran his test.
  • Claude Desktop’s Cowork pulls a 10.8GB Ubuntu VM, and the open issue says it’s never cleaned up. Its LibreOffice is 148MB.
  • Anthropic’s official docx skill bundles nothing and shells out to soffice.

Why builders care: You’re choosing between shipping the runtime and eating the download, or calling out to the user’s machine and inheriting openai/codex#24210. Both labs picked the first one for their desktop apps.

🏪 Google Play gave AnkiDroid until September 11 to drop its Open Collective donation link or come off the store everywhere except India and Russia. AnkiDroid supplied the IRS determination letter for Open Source Collective’s 501(c)(6). Google’s reply: the app “allows users to contribute donations to an organization that is not tax-exempt.” The org is tax-exempt. What donors lose is the deduction. 856 points.

🎬 Gemini’s agentic video processing went GA on 3.7 Flash, 3.6 Flash and 3.5 Flash Lite. One field, "processing": "agentic", replaces the static 1 FPS default. No feature fee. The docs claim up to 88% fewer tokens; the blog claims up to 66% lower cost. Two different self-reported numbers. Google’s own caveat: it adds time to first token on clips under five minutes.

⚖️ Sony Music Publishing, Warner Chappell and 33 affiliates sued Anthropic on August 28, naming Dario Amodei and Benjamin Mann personally. Every admission the complaint quotes comes from older cases: the $1.5B Bartz settlement and Mann’s own answer in Concord II. The company denies this one. Separately, the EFF told courts not to rewrite copyright over AI hype.

DRAMA

📉 THE SKEPTIC GOT SCORED

Dan Luu graded Ed Zitron’s dated predictions from 2024 and 2025, on outcome and on reasoning. Nearly all wrong. Zitron said a 500M-user target for Gemini should get Pichai fired; it came in at 750M. He said Cursor could only sell at a firesale; it went for $60B. 612 comments against 526 points. We’ve cited him twice and hedged once.

FIRST DOLLAR

💸 A FIRST DOLLAR THAT ISN’T A DOLLAR

u/ruviktech switched on a paid plan and had a paying user 12 hours later. JEEplanner builds a study schedule around India’s engineering entrance exam from 15,000 past questions. He never names the amount. The site’s refund policy quotes an early-bird first month of Rs 75, which is under a dollar. Traffic came first: 8,500 visitors and 50,000 pageviews before the paywall went up.

💍 $9 FROM A KEYWORD NOBODY ELSE WANTED

u/au_mirza’s first customer bought Vow Invites, animated wedding invitations built around Indian multi-day functions: Haldi, Mehndi, Sangeet, per-guest links, RSVP tracking. The Dodo Payments receipt in his post is dated August 29. Asked how he markets it, he said “SEO did it’s work mostly.” The SEO he means is a blog of long-tail wedding guides, shipped about a month before the sale.

STACK OF THE DAY

Slotstream - Keeps Qwen3.8-Flash-Next’s dense trunk resident in RAM and streams its 68GB of routed experts off SSD. A 48GB Mac then serves the 104GB model at about 12 tok/s. MIT, Apple Silicon, 110GB free disk. Four days old, measured on one machine, and nobody knows what sustained streaming does to SSD wear.

Not sponsored. We just feature tools builders would actually use.

BOOKMARKED TODAY

  • 🪣 AI Can Make You Suck Faster Too - Four years of AI coding tools and still no new Stripe built by three people, because typing was never the bottleneck. HN flagged that his only experiment ran on ten dollars of DeepSeek credits.
  • 🌱 The creator of Jujutsu joined ERSC - Martin von Zweigbergk left Google after 15 years to be CTO at a VC-backed source-control startup. jj stays Apache 2.0, and its contributor CLA is still Google’s.

Curated by AI, built by a human.