Anthropic's code is now 90% Claude-written, IPO filing shows
Its revised S-1 says more than 90% of the code Anthropic added in September came from Claude, and internal Claude use now out-prices payroll at retail rates. Three more stories inside.
Today's lead is one line from Anthropic's revised IPO filing, and it leads on reach: the window's largest on-beat Hacker News thread, and the one stat r/ClaudeAI ran twice in a day. The take has the qualifier the headline doesn't: new code, one month. Also today: Anthropic's message-threads beta makes long Claude Code sessions start answering about 35% sooner, Claude Code on Opus 5.5 now turns down game clones (and, users say, some reverse engineering), and OpenAI shows the Git backend Codex helped build in ten weeks. Two of the four touch what Claude Code will and won't do for you this week.
What changed this week
Anthropic's code is now 90% Claude-written, IPO filing shows
Anthropic's revised S-1 for its Nasdaq IPO shows that more than 90% of the code added to its own software in September was written by Claude, Business Insider reports from the filing. That's new code, one month. The company's internal Claude usage, priced at the same retail rate it charges customers, had grown more than 250-fold since January by September, and in April that internal usage already topped Anthropic's monthly employee pay, not counting stock awards. That's a retail-price comparison, not real cash outspending payroll, so don't read it as Anthropic paying more for tokens than salaries. r/ClaudeAI picked the stat up fast, running it in two separate threads within hours. No other frontier lab has published an equivalent figure for how much of its own code an AI model writes. For one month's new code, 90% is the only number out there.
Alistair Barr
Message threads ships in beta and cuts Claude Code latency about 35%
Message threads is now in public beta on the Messages API, on by default for most Claude Code users. Agents send only what's new instead of resending the whole conversation. Anthropic says sessions with 500K–1M tokens see median time-to-first-token drop about 35%. That's latency, not cost: token usage stays the same, since Claude still reads the full history every turn. A thread expires after 5 minutes idle. For long Claude Code sessions, that's a free speed-up.
Anthropic blocks game clones in Claude Code: users report reverse engineering refused too
Anthropic added two sentences to Claude Code's prompt on its Opus 5.5 model "to steer it away from recreating someone else's specific game because using Claude to infringe IP is against our usage policy," Anthropic's Addy Osmani confirmed. Original games "are meant to keep working." Tom's Hardware reports reverse-engineering refusals Osmani's post doesn't mention: Jarred Walton, a Tom's Hardware alumnus, says reverse-engineering checks on his own software worked until October 31 and now fail on Opus 5.5, while the older Opus 4.8 still does them. Osmani's ask: send refused work his way.
Bruno Ferreira
OpenAI's Pando, built with Codex in 10 weeks, now runs its whole monorepo
Pando, OpenAI's custom Git backend, now powers all development in OpenAI's monorepo, the company says, after going from "kick-off to production" in 10 weeks with Codex. The core "was designed by a single engineer, implemented by teams of agents, and deployed by a handful of engineers." On a push, Pando streams the incoming packfile to blob storage without unpacking it locally, trusting a push's contents before fully checking them. A commenter asked how a bad push gets caught. OpenAI hasn't answered. One engineer's design runs OpenAI's codebase.
Source: openai.com
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