{"name":"systemPromptSnapshot","slug":"systempromptsnapshot","family":"setting","title":"Settings keys","noun":"settings key","description":"A new --system-prompt-snapshot option makes a session record its system prompt once and reuse it on resume.","description_source":"entry","described_by":{"version":"2.1.257","anchor":"new-system-prompt-snapshot-cliagent-option"},"presence":{"first_seen":"2.1.315","removed_in":"2.1.317","in_current_build":false,"newest_mined":"2.1.319","builds":2,"mined_builds":159,"first_cited":{"version":"2.1.257","released_at":"2026-09-01 17:15:33","spans":4}},"aliases":[],"entries":[{"version":"2.1.280","anchor":"custom-system-prompt-updates-now-apply-only-after-compaction","heading":"Custom system prompt updates now apply only after compaction (unless systemPromptSnapshot:false)","line":"SDK custom system prompt updates now apply after the next compaction, not the next turn","released_at":"2026-09-22 15:44:39","reason":"found in this entry's text, named in this entry"},{"version":"2.1.274","anchor":"system-prompt-hot-swap-now-takes-effect-from-the-next-turn","heading":"System-prompt hot-swap now takes effect from the next turn, not at next compaction","line":"Swapping the system prompt mid-session now applies from the next turn instead of waiting for compaction","released_at":"2026-09-16 22:36:09","reason":"named in this entry, found in this entry's text"},{"version":"2.1.274","anchor":"headless-sdk-sessions-now-detect-and-re-inject-a-changed-sys","heading":"Headless SDK sessions now detect and re-inject a changed system prompt mid-session","line":"Headless SDK sessions now detect a changed system prompt mid-session and re-inject it into the transcript","released_at":"2026-09-16 22:36:09","reason":"named in this entry, found in this entry's text"},{"version":"2.1.260","anchor":"get-context-usage-no-longer-factors-in-appendsubagentsystemp","heading":"get_context_usage no longer factors in appendSubagentSystemPrompt","line":"Context-usage estimates for embedding hosts no longer count the subagent system-prompt append.","released_at":"2026-09-03 22:32:02","reason":"found in this entry's text"},{"version":"2.1.259","anchor":"background-sessions-get-a-narrower-permission-snapshot","heading":"Background sessions get a narrower permission snapshot","line":"Background sessions run with session allow-rules cleared and a narrower set of working directories, and always snapshot the system prompt.","released_at":"2026-09-02 21:21:42","reason":"found in this entry's text, named in this entry"},{"version":"2.1.257","anchor":"new-system-prompt-snapshot-cliagent-option","heading":"New --system-prompt-snapshot CLI\/agent option","line":"A new --system-prompt-snapshot option makes a session record its system prompt once and reuse it on resume.","released_at":"2026-09-01 17:15:33","reason":"found in this entry's text"},{"version":"2.1.257","anchor":"new-hideloginnotice-session-option","heading":"New hideLoginNotice session option","line":"A new hideLoginNotice option lets a host session hide the login notice without hiding all welcome chrome.","released_at":"2026-09-01 17:15:33","reason":"found in this entry's text"},{"version":"2.1.257","anchor":"systempromptsnapshot-option-for-records-the-system-prompt-on","heading":"systemPromptSnapshot option for records the system prompt once per conversation","line":"A systemPromptSnapshot option freezes the system prompt for a conversation, so mid-session changes wait for compaction.","released_at":"2026-09-01 17:15:33","reason":"named in this entry, found in this entry's text"},{"version":"2.1.257","anchor":"get-context-usage-command-gains-detail-level-and-system-prom","heading":"get_context_usage command gains detail level and system-prompt snapshot input","line":"Context-usage requests can specify a detail level and pin the system prompt snapshot used for the calculation.","released_at":"2026-09-01 17:15:33","reason":"found in this entry's text, named in this entry"},{"version":"2.1.257","anchor":"new-system-prompt-snapshot-plumbed-into-mcptool-context","heading":"New system prompt snapshot plumbed into MCP\/tool context","line":"The tool and agent context now exposes a snapshot of the system prompt in effect alongside the appended one.","released_at":"2026-09-01 17:15:33","reason":"found in this entry's text, named in this entry"}],"entries_total":10,"docs":[],"docs_total":0,"gates":[],"related":[],"url":"https:\/\/changelogs.core-directive.com\/reference\/setting\/systempromptsnapshot","family_url":"https:\/\/changelogs.core-directive.com\/reference\/setting.json"}