Add /clear command

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -3,6 +3,13 @@
 All notable changes to CodeCraft. Versions follow [Semantic Versioning](https://semver.org/);
 until 1.0, minor versions may contain breaking changes.
 
+## [Unreleased]
+
+### Added
+
+- **`/clear`**: the model forgets the conversation so far; the chat keeps showing it, a divider marks
+  the cut. Also starts a fresh session with Claude Code.
+
 ## [v202611-00029] – 2026-11-15
 
 ### Added

server/src/api.rs

@@ -1128,6 +1128,13 @@ pub(crate) fn send_prompt(app: &AppState, session: crate::types::Session, text:
         tokio::spawn(do_compact(app.clone(), id.clone()));
         return Ok(json!({"ok": true, "command": "compact"}));
     }
+    if text == "/clear" {
+        if app.is_busy(&id) {
+            return Err(ApiError(StatusCode::CONFLICT, "session is busy".into()));
+        }
+        runner::clear_context(app, &id).map_err(|e| ApiError(StatusCode::INTERNAL_SERVER_ERROR, format!("{e:#}")))?;
+        return Ok(json!({"ok": true, "command": "clear"}));
+    }
     let cwd = PathBuf::from(&session.cwd);
     let root = app.root_for(session.owner_id.as_deref(), &cwd);
     let mut prompt_text = text.clone();

server/src/runner.rs

@@ -1723,10 +1723,43 @@ async fn compact_inner(app: Arc<App>, session_id: &str, cancel: CancellationToke
     Ok(())
 }
 
+/// Text of the marker `/clear` puts into the history (the chat view recognises it).
+pub const CLEARED_MARKER: &str = "[Context cleared by the user. Earlier messages are no longer part of this conversation – start fresh and do not refer to them.]";
+
+/// `/clear`: the model forgets the conversation so far (the chat keeps showing it). Like a
+/// compaction without a summary: history before the marker is not sent any more.
+pub fn clear_context(app: &App, session_id: &str) -> Result<()> {
+    save_user_parts(app, session_id, vec![Part::Summary { text: CLEARED_MARKER.into(), auto: false, tokens: None }])?;
+    app.update_session(session_id, |s| {
+        s.last_usage = None;
+        s.todos = Value::Null;
+    })?;
+    app.with_runtime(session_id, |r| r.read_files.clear());
+    // Claude Code continues its own conversation: start a new one.
+    if let Some(owner) = app.session(session_id).ok().and_then(|s| s.owner_id) {
+        let _ = app.store.set_user_setting(&owner, &format!("claude_sid:{session_id}"), &Option::<String>::None);
+    }
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    #[test]
+    fn cleared_marker_starts_a_new_history() {
+        let mk = |role, parts| Message::new(role, parts);
+        let all = vec![
+            mk(Role::User, vec![Part::Text { text: "old question".into() }]),
+            mk(Role::Assistant, vec![Part::Text { text: "old answer".into() }]),
+            mk(Role::User, vec![Part::Summary { text: CLEARED_MARKER.into(), auto: false, tokens: None }]),
+            mk(Role::User, vec![Part::Text { text: "new question".into() }]),
+        ];
+        let active = active_history(all);
+        assert_eq!(active.len(), 2);
+        assert!(!active.iter().any(|m| message_text(m).contains("old")));
+    }
+
     #[test]
     fn fit_keeps_head_and_tail_within_budget() {
         let text = format!("{}{}{}", "A".repeat(5000), "M".repeat(5000), "Z".repeat(5000));

web/src/components/ChatView.tsx

@@ -459,13 +459,15 @@ const MessageItem = memo(function MessageItem({ m, canEdit, onRewind, highlight
     return (
       <details className="summary-divider" data-mid={m.id} onToggle={(e) => setSummaryOpen((e.currentTarget as HTMLDetailsElement).open)}>
         <summary>
-          {summary.auto
+          {summary.text.startsWith("[Context cleared")
+            ? t("chat.cleared")
+            : summary.auto
             ? t("chat.compactedAuto", { tokens: summary.tokens ? fmtCompact(summary.tokens) : "?" })
             : summary.tokens
               ? t("chat.compactedManual", { tokens: fmtCompact(summary.tokens) })
               : t("chat.compacted")}
         </summary>
-        {summaryOpen && <Markdown text={summary.text} />}
+        {summaryOpen && !summary.text.startsWith("[Context cleared") && <Markdown text={summary.text} />}
       </details>
     );
   }

web/src/components/Composer.tsx

@@ -20,6 +20,7 @@ interface Suggestion {
 
 const BUILTIN: { name: string; key: Key }[] = [
   { name: "compact", key: "command.compact" },
+  { name: "clear", key: "command.clear" },
   { name: "new", key: "command.new" },
 ];
 

web/src/i18n/de.ts

@@ -1144,4 +1144,6 @@ export const de: Messages = {
   "stats.table.agent": "nach Modus",
   "stats.table.user": "nach Benutzer",
   "stats.table.session": "teuerste Chats",
+  "command.clear": "Bisheriges Gespräch vergessen (der Chat bleibt sichtbar)",
+  "chat.cleared": "Kontext geleert – das Modell sieht die Nachrichten darüber nicht mehr",
 };

web/src/i18n/en.ts

@@ -1143,6 +1143,8 @@ export const en = {
   "stats.table.agent": "by agent",
   "stats.table.user": "by user",
   "stats.table.session": "top chats",
+  "command.clear": "Forget the conversation so far (the chat stays visible)",
+  "chat.cleared": "Context cleared – the model no longer sees the messages above",
 };
 
 export type Messages = Record<keyof typeof en, string>;

web/src/whatsnew.ts

@@ -3,6 +3,10 @@
  * under "unreleased"; scripts/release.sh renames the key to the release version.
  */
 export const WHATS_NEW: Record<string, { en: string[]; de: string[] }> = {
+  unreleased: {
+    en: ["/clear: the model forgets the conversation so far, the chat stays visible"],
+    de: ["/clear: das Modell vergisst das bisherige Gespräch, der Chat bleibt sichtbar"],
+  },
   "202611-00029": {
     en: [
       "Statistics: foldable sections, years of history with a year filter, export as XLSX/CSV",