How Claude Code uses prompt caching changedprompt-caching
Nearest release: v2.1.290, published 4 hours before upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.
Upstream edited this page at 5 Oct 2026 22:35 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 5 Oct 2026 22:37 UTC.
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215215Your project-root and user-level CLAUDE.md files are read once at session start and held in memory. Editing them mid-session does not invalidate the cache, but the edit also doesn't apply. Claude keeps working with the version that was loaded at session start. The new content loads on the next `/clear`, `/compact`, or restart.
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217[Nested CLAUDE.md files in subdirectories](/docs/en/memory) and [rules with `paths:` frontmatter](/docs/en/memory#path-specific-rules) load later, when Claude first reads a matching file. Editing one before it loads does take effect. After it loads, the content is part of the conversation history, so a mid-session edit doesn't retroactively change it.
217[Nested CLAUDE.md files in subdirectories](/docs/en/memory) and [rules with `paths:` frontmatter](/docs/en/memory#path-specific-rules) load later, when Claude first reads a matching file. Editing one yourself before it loads does take effect. After it loads, the content is part of the conversation history, so a mid-session edit doesn't retroactively change it.
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219219### Changing permission mode
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