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Sweep 27 Oct 2026 · 19:04Z Build v2.1.312 531 read Stable v2.1.308 Latest v2.1.312 Next v2.1.312 Feeds RSS JSON llms.txt llms-full.txt Unofficial
HomeDocsClaude Code CLI 27 Oct 2026
One change · claude-code

Modifying system prompts changedagent-sdk/modifying-system-prompts

Nearest release: v2.1.312, published 2 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 27 Oct 2026 20:59 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 27 Oct 2026 21:07 UTC.

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422422Set `includeGitInstructions` to `false` to keep out the built-in commit and pull request instructions, which are part of the Bash tool's description and reach Claude even with a custom `systemPrompt`. With the minimal default, a custom `systemPrompt`, or a custom main-thread agent that has its own prompt, though, the session starts without the git status snapshot.
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424If you set `CLAUDE_CODE_DISABLE_ATTACHMENTS`, Claude Code also sends `@` file mentions as plain text instead of expanding them into file content. The list of available subagents and background task notifications still arrive. To stop only `@` file mentions from expanding, set [`CLAUDE_CODE_DISABLE_FILE_MENTIONS=1`](https://code.claude.com/docs/en/env-vars#variables) instead, on Claude Code v2.1.299 or later. Claude then gets the mentioned paths plus a note to read them with its file tools.
424* If you set `CLAUDE_CODE_DISABLE_ATTACHMENTS`, Claude Code also sends `@` file mentions as plain text instead of expanding them into file content. The list of available subagents and background task notifications still arrive.
425* To stop only `@` file mentions from expanding, set [`CLAUDE_CODE_DISABLE_FILE_MENTIONS=1`](https://code.claude.com/docs/en/env-vars#variables) instead, on Claude Code v2.1.299 or later. Claude then gets the mentioned paths plus a note to read them with its file tools, and your `PreToolUse` hooks see each file read as a tool call.
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426427The following example is for an agent that carries its own commit rules in `append`. It sets both `attribution` keys to empty strings to remove the trailer and footer, and turns off `includeGitInstructions` so Claude Code's own commit workflow instructions don't compete with yours:
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