Always post bad news on a holiday
Anthropic's guide to creating effective agent harnesses
The newsletter for the technically curious. Updates, tool reviews, and lay of the land from an exited founder turned investor and forever tinkerer.
Hey folks, Happy Thanksgiving to those celebrating! Light edition today…
Classic move from OpenAI - dropping a data breach disclosure at 10pm the night before Turkey day. Brilliant PR timing.
OpenAI disclosed a Mixpanel security incident that exposed API user data - names, emails, user IDs, and location info. No ChatGPT data or API keys were compromised. OpenAI has terminated its Mixpanel use entirely (no shit!).
Meanwhile, OpenAI needs to raise at least $207 billion by 2030 [paywalled] to keep the lights on, according to HSBC. This is after their commitments to Oracle ($300B), Microsoft ($250B), and AWS ($38B) for cloud services. The FT called OpenAI “a money pit with a website on top.” 🫠
Anthropic dropped two bangers this week. First, Effective harnesses for long-running agents - a deep dive into how they get Claude to work across multiple context windows without losing the plot. The key insight: use an initializer agent to set up the environment, then a coding agent that makes incremental progress and leaves clean artifacts for the next session. They built a Claude.ai clone this way.
[But Factory’s harness is better]
Second, Estimating AI productivity gains - they analyzed 100K real Claude conversations and found AI reduces task completion time by ~80%. Extrapolating this, they estimate current AI could increase US labor productivity by 1.8% annually over the next decade - roughly doubling recent growth rates. The caveat: this doesn’t account for time humans spend validating outputs outside the chat window.
A little update from my portfolio:
San Francisco Compute - raised $40M at a $300M valuation - marketplace for AI computing capacity. (I’m an early investor) + they’re hiring
Plus some other investments have been on a tear recently;
Gamma @ $2.5bn valuation - I invested as an a16z scout, they led the latest round.
Supabase @ $5bn
Scribe @ $1.3bn
My 2020/2021 fund is now over 4x / 36% IRR
Ben’s Bites Fund I is 2x / 39% IRR (2023-2025)
Ben’s Bites Fund II did its first close, and is still open to new LPs. Get in touch if you’re interested.
Here’s a few YC companies I’m looking at:
Sourcebot - Self-hosted code search and AI Q&A for your entire codebase.
Metorial - Serverless MCP hosting with 600+ integrations. Deploy MCP servers in 3 clicks, instant observability.
SF-Tensor - Cross-cloud GPU orchestration that finds the cheapest hardware and auto-optimizes your training kernels.
S2.dev - Serverless durable streams API. Like if Kafka and S3 had a baby - unlimited, real-time, bottomless storage.
Hyperspell - Context and memory layer for AI agents.
Crunched - AI analyst that works natively inside Excel.
🌐 What I’m consuming
Ilya Sutskever – We’re moving from the age of scaling to the age of research
I don’t care how well your “AI” works - a rant about AI product fatigue.
⚙️ Tools and demos
AskCodi - Custom LLMs without training, accessible via OpenAI-compatible API
Flux 2 - image generation & editing model. Multi-reference. 4MP. Production-ready. Open weights.
Penpot - The open-source design tool for design and code collaboration (open-source Figma)
🥣 Dev dish
Era - Open-source local sandbox for AI agents. Run agents safely without cloud dependencies.
Rubberduck - Catch App Store rejection issues before Apple does
Prime Intellect launched INTELLECT-3: Scaling RL to a 100B+ MoE model on our end-to-end stack
🍦 Afters
Jeff Bezos’ Project Prometheus quietly acquired General Agents, an agentic AI startup founded by ex-DeepMind and OpenAI researchers. Their agent “Ace” can autonomously control computers and perform complex tasks. Project Prometheus has raised $6.2B and now has 100+ employees, all focused on AI for manufacturing - computers, cars, spacecraft. Bezos is back in operator mode.
That’s it for today. Feel free to comment and share your thoughts. 👋
Read about me and Ben’s Bites
📷 thumbnail creds: @keshavatearth,
Wanna partner with us? Last few slots left for the rest of the year.
The Anthropic harness approach makes alot of sense. Using an initializer agent to prep the environemnt and then a coding agent that leaves clean artifacts between sessions feels like a more sustainable pattern than stuffing everything into one bloated context.
Claude code was made by an ex-Meta IC7 🤯