Semble (v0.1.7, May 12) is a code search library for AI agents that uses ~98% fewer tokens than grep+read while matching 99% of the retrieval quality of much heavier transformer-based approaches. It indexes a repository in 263ms and answers queries in 1.5ms on CPU, ships as an MCP server for Claude Code, Cursor, and Codex, and requires no API keys, GPU, or external services. The design bets that static embeddings plus BM25, fused carefully and reranked with code-specific signals, are almost as good as a code-specialized transformer — and orders of magnitude cheaper to operate.
Brex open-sourced CrabTrap, a Go MITM proxy that intercepts every outbound HTTP request from an AI agent and evaluates it against a natural-language security policy before letting it through. The approach is genuinely useful for catching exfiltration attempts, while raising a fair question about whether a probabilistic judge belongs in a security-critical path.
Sebastian Raschka published a technical breakdown of what a coding agent harness actually needs — six components that often matter more than the model itself. The same day, Imbue's case study on running 100+ Claude agents in parallel to test and improve their own tooling arrived on Hacker News. Together they sketch what production-grade agent engineering looks like right now.
Andrej Karpathy published a pattern for persistent, compounding LLM knowledge bases — a structured wiki that grows smarter with each query rather than re-deriving knowledge from raw documents every time. The more interesting detail is how he shared it: not as code, but as an "idea file" — a new format for the agent era where you hand a spec to someone's agent and it builds the implementation for you.
