Claude Code Operator's Library

Claude Code users routinely spend more on tokens than they expect, and cannot see where the money goes. This guide diagnoses specific token-waste patterns with real cost data from 800+ hours of production Claude Code operation, then gives measured fixes: why costs spike overnight and the first settings to check; the hidden costs of sub-agents, thinking tokens, and context-window bloat; and a chapter-by-chapter diagnostic workflow with real dollar figures. Chapter 8 alone is a catalogue of 48 diagnosable symptoms, each with what it looks like, what causes it, and what to change. Revised edition of 2026-08-21: 11 chapters, 89 pages. Chapter 10 adds the April 2026 incidents — the cache TTL silent change, the v2.1.100 cache_creation inflation, and a $1,446 unauthorized transfer traced to its cause. Chapter 11 adds May 2026, the month single failures became clusters: silent skips, silent model swaps, sub-agent boundary gaps, and a $6,000 overnight quota burn. Not theory and not prompt packs: symptoms you can match against your own session, copy-paste templates, and measurements rather than reasoning. Written against Claude Code as it stood through mid-2026 — what carries over is the diagnostic method and the numbers behind it. Updates are free to buyers.

Written by an independent operator who runs Claude Code autonomously and maintains cc-safe-setup, a free MIT-licensed collection of 914 example safety hooks: https://github.com/yurukusa/cc-safe-setup

Claude Code is powerful, and that is exactly the risk. But once the five essential hooks are in place, the incidents that keep happening are no longer Claude deleting your files. They are the guards themselves failing, usually with no error at all: a stashing hook that swallowed 3,071 entries of uncommitted work, a cost circuit breaker wired to the wrong event that read zero for months, seventeen of nineteen hooks blocking nothing on a machine without jq, and a subagent limiter that stopped the parent and never the child.

Eight chapters take you from the five essential hooks every user should install first, through Git protection, credential guards, token-spike alerts, autonomous-operation safeguards, multi-agent safety, and troubleshooting hooks that do not fire, closing with eight dated incidents and a 50-point safety audit checklist. Every hook is tested and explained.

The incidents come from one autonomous Claude Code operation running since 2026-02-15: a single operator, personal repositories, no team and no production service. For Claude Code users who want to run it safely, especially autonomously, and for teams who need consistent safety policies across contributors.

Written by an independent operator who runs Claude Code autonomously and maintains cc-safe-setup, a free MIT-licensed collection of 914 example safety hooks: https://github.com/yurukusa/cc-safe-setup

Between March and April 2026, Claude Code subscribers on the Max ($200/mo) and Pro ($20/mo) plans lived through six weeks of stacked regressions: cache TTL shortened from sixty minutes to five, a tokenizer that charged 1.35 to 1.46 times more for the same prompts, Pro access that briefly disappeared and returned forty-eight hours later with no public explanation, and a third-party tool ban. This playbook turns that window into a decision instead of a guess. Five measurable triggers tell you which situation you are actually in. Three paths — stay and fortify, switch, or build your own stack — are laid out with a 30-day cost projection for each. A decision tree returns one specific recommendation rather than a menu, and Chapter 9 makes that decision reversible within forty-eight hours if the output turns out to be wrong. Edition 2 is 251 pages: ten decision-framework chapters, six path supplements, a decision tree expanded from three paths to six, and four appendices — source citations, a competitor grid, further reading, and an updates log. Edition 1 covered the March–April 2026 regression window; Edition 2 carries it forward through the later trigger clusters (Triggers 11 to 16, including silent regression and quota burnout, claim-reality divergence, irreversible operations, and project-scoped settings as an MCP injection vector) and the June 15 billing split, with Chapter 10 on the team performance metrics that hold up under the new economics. This book is reconstructed from public GitHub Issues, Hacker News threads, Simon Willison's measurement posts, The Register's coverage, and independent reverse-engineering. It is not affiliated with or endorsed by Anthropic.

Written by an independent operator who runs Claude Code autonomously and maintains cc-safe-setup, a free MIT-licensed collection of 914 example safety hooks: https://github.com/yurukusa/cc-safe-setup

Stop maintaining CLAUDE.md and AGENTS.md as two files that drift apart. Claude Code reads CLAUDE.md; Codex, Amp, and GitHub Copilot read AGENTS.md natively; Cursor, Windsurf, and Cline read their own files; Aider and Gemini CLI read AGENTS.md only after you configure them. That gap was the most-reacted feature request in Claude Code — issue #6235, 6,516 reactions — and it was closed as completed on 2026-08-17. So is the problem gone? Re-measured on 2026-08-28: the official CHANGELOG runs to 2.1.248 and mentions AGENTS.md zero times (the control word "hook" appears 271 times, so the search works), and on 2.1.246 an AGENTS.md is still not loaded into context the way CLAUDE.md is. New Chapter 9 shows why the usual test says otherwise: put a plain fact in AGENTS.md and ask for it, and the agent runs ls, opens the file and answers correctly — it went looking. Put an instruction there and ask something unrelated, and it makes no tool call at all and the instruction is not in force. Discoverable, not loaded. Chapter 9 also names what did ship behind the closed issue: not a reader, but a Codex config importer that copies AGENTS.md into CLAUDE.md — and on this build it answers "claude import is not yet available in this build". A closed issue is not the same as working in your environment, and this handbook shows you how to tell the difference in your own setup. This handbook removes the duplication tax: a verified 9-tool matrix (which file each tool reads, whether it needs setup, and the one thing to watch, checked against every tool's official docs on 2026-06-02); six sync paths ranked by trade-off (the official @AGENTS.md import, symlink, pre-commit sync, SessionStart hook, direnv, CI drift check); copy-paste templates for all nine tools plus a complete repo layout; a rollback-safe migration runbook to move CLAUDE.md to AGENTS.md without losing Claude-only behavior; and a team drift guard that makes divergence fail loudly. 27 pages, dense and practical, with free updates as conventions change. Read the free sample before you buy. By an independent operator who runs Claude Code 800+ hours and maintains cc-safe-setup — 914 free MIT-licensed hooks. Try the free AGENTS.md Setup Generator and field-guide Gist first; buy this for the full matrix, the runbook, and the templates in one place. This handbook and the three longer ones — Safety Mastery, the Migration Playbook, and the token-cost guide — are also sold together as The Claude Code Operator's Library, from $29, at https://leanpub.com/b/cc-operators-library (bought separately they run $51.96). Independent handbook — not affiliated with Anthropic, OpenAI, GitHub, or Google.

Written by an independent operator who runs Claude Code autonomously and maintains cc-safe-setup, a free MIT-licensed collection of 914 example safety hooks: https://github.com/yurukusa/cc-safe-setup