Claude Code startup load trimmed: CLAUDE.md halved from 6.1k to 3.3k chars

The official Claude Code documentation says one thing; the author does another in their own setup. On the documentation side, the core advice is to write requests down to the target file or function, keep CLAUDE.md under 200 lines, move multi-step procedures into skills whose bodies load only when used, tag rule files with paths so they load only when matching files are touched, match the model and effort level to the task, disable unused MCP servers, and push long outputs to subagents or output-filtering hooks. As context, the official cost page cites an enterprise average of about $13 per developer per working day (monthly $150–250), with 90% of users under $30 a day, while noting this is an API cost benchmark, not a subscription bill or weekly limit number.

The author's own experiment seems to have come from an unattended claude -p setup that could launch up to 10 times an hour. The measurement on 2026-11-07 showed that the instructions loaded at every launch — CLAUDE.md, shared rules, work instructions, the index — totaled about 45,000 characters. Three changes followed: moving history, known issues and test results out of the unattended folder's CLAUDE.md (about 6,100 to about 3,300 characters), rewriting the index about 25% shorter, and instructing later restarts not to re-read rules and the index. The author frames the common thread simply as sorting by whether something must be read every time.