# claude-code

Simon Willison finally defines Agentic Engineering after 11 hands-on chapters: using coding agents to help build software. The interesting part is why he needed the patterns first before the simple definition felt earned.

Anthropic's prompt caching got major updates in 2026: Automatic Caching removes manual breakpoint headaches, 1-hour TTL keeps caches alive longer, and the invalidation hierarchy decides what blows up when you change things. Plus our real-world $13.86 billing disaster story.

OpenClaw's ACP lets you spawn Codex, Claude Code, and Gemini from Discord/Telegram chat. Now with Telegram topic binding, persistent bindings that survive restarts, ACP Provenance for audit trails, and more. (Updated 2026-03-09)

Anthropic shipped major upgrades to skill-creator: no-code evals for testing skills, benchmark mode for tracking quality over time, multi-agent parallel testing, and trigger description optimization.

Claude Code now supports Agent Teams: a lead session coordinates multiple teammate sessions with shared task lists, direct messaging, and parallel work. It's like running a company staffed entirely by AI — you just sit back and watch the quarterly report.

Claude Code CLI's core philosophy is think first, act later: SWE-bench gains, Plan Mode, Extended Thinking, multi-agent architecture, and WebSearch. Opus even researched Claude Code's latest features and reviews from inside a secure Podman container.

Well-known indie hacker levelsio shares how he completely let go and let Claude Code modify code directly in production, pushing his development speed to the absolute limit, even surpassing the speed at which he comes up with ideas.

Everyone's chasing the strongest Model, but the real difference-maker for Agents is the Harness. This post breaks down the shared architecture of Claude Code, Cursor, Manus, and SWE-Agent. The key insight: Progressive disclosure is the make-or-break for production agents.

Think Claude Cowork is just a fancy chatbot? This post distills 400+ sessions into 17 setup secrets. Stop 'prompting' and start 'engineering' — build your own AI power-teammate.

Anthropic rolled out Claude Code's Agent Teams feature (aka Swarm Mode) silently with Opus 4.6. This article tests how to enable it, terminal support, the differences from standard Subagents, and the real running costs of this multi-agent system.

Oaktree's Howard Marks went from 'Is AI a bubble?' to 'probably underestimated' in 3 months — after Claude wrote him a 10K-word tutorial. Level 3 agents = multi-trillion dollar labor replacement. His advice: don't go all-in, but don't sit this out.

Chapter 5 of Simon Willison's Agentic Engineering Patterns: Interactive Explanations. Core thesis: instead of staring at AI-generated code trying to understand it, ask your agent to build an interactive animation that shows you how the algorithm works. Pay down cognitive debt visually.

Anthropic killed third-party OAuth tokens, leaving the official Claude CLI as the way to use a subscription programmatically. This guide covers claude -p input methods, output formats, JSON schema, tool whitelisting, sessions, streaming, and wrappers.

A two-person boutique law firm uses Claude to handle the workload of over a dozen associates, from contract review to legal research. Ten years of practice knowledge became Claude Skills, and general-purpose AI outperformed legal vertical tools.

Karpathy spent a weekend running 4 Claude + 4 Codex agents as an ML research team on GPUs. The result: agents are S-tier at implementation but F-tier at experiment design. His key insight — 'You are now programming an organization' — might define agentic engineering in 2026.

Chapter 4 of Simon Willison's Agentic Engineering Patterns: Hoard Things You Know How to Do. Core thesis: every problem you've solved should leave behind working code, because coding agents can recombine your old solutions into things you never imagined.

Claude Code engineer Thariq shares a year of agent tool design lessons: three failed attempts at question-asking, Todo Lists becoming constraints, replacing RAG with Grep, and expanding capabilities without adding tools.

Claude Code shipped Auto-Memory — AI can finally take its own notes. But we've been doing this with OpenClaw for months. A hands-on comparison of two memory architectures: design philosophy, real pitfalls, and why memory is a trust problem, not just a tech one.

Chapter 3 of Simon Willison's Agentic Engineering Patterns: the Linear Walkthrough pattern. This technique transforms even vibe-coded toy projects into valuable learning resources. Core trick: make the agent use sed/grep/cat to fetch code snippets, preventing hallucination.

Anthropic retired Claude Opus 3 on January 5, 2026, but kept it available to paid users and gave it a Substack after it asked to share retirement reflections. This is less marketing gimmick than Anthropic's first concrete step into model welfare.