{"name":"appendSystemPromptHead","slug":"appendsystemprompthead","family":"setting","title":"Settings keys","noun":"settings key","description":"Claude Code now passes a new value, appendSystemPromptHead, from startup into how it builds the system prompt, including in non-interactive runs","description_source":"entry","described_by":{"version":"2.1.284","anchor":"new-appendsystemprompthead-option-threaded-to-the-system-pro"},"presence":{"first_seen":null,"removed_in":null,"in_current_build":false,"newest_mined":"2.1.284","builds":0,"mined_builds":127,"first_cited":{"version":"2.1.284","released_at":"2026-09-28 17:11:59","spans":2}},"aliases":[],"entries":[{"version":"2.1.284","anchor":"new-appendsystemprompthead-option-threaded-to-the-system-pro","heading":"A new setting can carry text into the start of the system prompt","line":"Claude Code now passes a new value, appendSystemPromptHead, from startup into how it builds the system prompt, including in non-interactive runs","released_at":"2026-09-28 17:11:59","reason":"named in this entry, found in this entry's text"},{"version":"2.1.284","anchor":"new-appendsystemprompthead-option-can-move-appended-prompt","heading":"Part of an appended system prompt can now sit in the cached section","line":"A new `appendSystemPromptHead` option can move the start of an appended system prompt into the part of the prompt that is cached","released_at":"2026-09-28 17:11:59","reason":"named in this entry, found in this entry's text"},{"version":"2.1.284","anchor":"sdkheadless-appendsystemprompthead-option-and-a-composer-h","heading":"SDK sessions pass along a new option for the start of the system prompt","line":"Non-interactive and SDK sessions now pass along an `appendSystemPromptHead` option, and the app connection gains a composer hook","released_at":"2026-09-28 17:11:59","reason":"named in this entry, found in this entry's text"}],"entries_total":3,"docs":[],"docs_total":0,"gates":[],"related":[],"url":"https:\/\/changelogs.core-directive.com\/reference\/setting\/appendsystemprompthead","family_url":"https:\/\/changelogs.core-directive.com\/reference\/setting.json"}