feat(tui+server): /compact conversation compaction

src/server/agent_server.py

@@ -221,6 +221,9 @@ async def _handle_control_request(self, msg: dict) -> None:
         if subtype == "get_context_usage":
             self._reply(request_id, self._context_usage())
             return
+        if subtype == "compact":
+            await self._do_compact(request_id, inner.get("instructions"))
+            return
         # Unknown subtype — error back so a correlating client doesn't hang.
         if isinstance(request_id, str):
             self._emit({
@@ -302,6 +305,37 @@ def _context_usage(self) -> dict:
             out["error"] = str(exc)
         return out
 
+    async def _do_compact(self, request_id: object, instructions: object) -> None:
+        """Manually compact the conversation (the original's /compact). Idle-only:
+        the worker thread mutates the conversation during a turn, so refuse
+        mid-turn rather than race the message list."""
+        with self._lock:
+            active = self._current_abort is not None
+        if active:
+            self._reply(request_id, {"ok": False, "error": "cannot compact during an active turn"})
+            return
+        try:
+            from src.compact_service.service import compact_conversation
+
+            model = getattr(self.provider, "model", None) or self.config.model or ""
+            instr = instructions if isinstance(instructions, str) and instructions.strip() else None
+            res = await compact_conversation(
+                self.session.conversation,
+                self.provider,
+                model,
+                custom_instructions=instr,
+                trigger="manual",
+            )
+            self._reply(request_id, {
+                "ok": True,
+                "tokens_saved": res.tokens_saved,
+                "pre_compact_count": res.pre_compact_count,
+                "post_compact_count": res.post_compact_count,
+            })
+        except Exception as exc:  # noqa: BLE001
+            logger.exception("[agent-server] compact failed")
+            self._reply(request_id, {"ok": False, "error": str(exc)})
+
     def _resolve_permission(self, msg: dict) -> None:
         response = msg.get("response")
         if not isinstance(response, dict):

ui-tui/src/App.tsx

@@ -489,6 +489,32 @@ export function App({ transport, serverLabel }: Props): React.ReactElement {
         }
         return true
       }
+      case 'compact': {
+        if (client) {
+          addEntry({ kind: 'system', text: 'Compacting conversation…' })
+          void client
+            .requestControl('compact', arg ? { instructions: arg } : {}, 120_000)
+            .then((r) => {
+              if (r && r['ok']) {
+                const saved = Number(r['tokens_saved']) || 0
+                const pre = Number(r['pre_compact_count']) || 0
+                const post = Number(r['post_compact_count']) || 0
+                const sv = saved >= 1000 ? `${(saved / 1000).toFixed(1)}k` : String(saved)
+                addEntry({
+                  kind: 'system',
+                  text: `Compacted ${pre} → ${post} messages · saved ${sv} tokens`,
+                })
+                void client.requestControl('get_context_usage').then(applyContextUsage)
+              } else {
+                addEntry({
+                  kind: 'error',
+                  text: `compact failed: ${r && r['error'] ? String(r['error']) : 'no response'}`,
+                })
+              }
+            })
+        }
+        return true
+      }
       case 'control': {
         if (!arg) {
           addEntry({ kind: 'system', text: `usage: ${cmd.name} <value>` })

ui-tui/src/slashCommands.ts

@@ -7,7 +7,7 @@ export interface SlashCommand {
   name: string
   description: string
   /** how the command is handled when submitted. */
-  kind: 'clear' | 'help' | 'quit' | 'control' | 'context' | 'send'
+  kind: 'clear' | 'help' | 'quit' | 'control' | 'context' | 'compact' | 'send'
   /** for kind:'control' — the control_request subtype. */
   control?: string
 }
@@ -23,6 +23,7 @@ export const SLASH_COMMANDS: SlashCommand[] = [
     control: 'set_permission_mode',
   },
   { name: '/context', description: 'Show context-window usage by category', kind: 'context' },
+  { name: '/compact', description: 'Summarize & compact the conversation: /compact [instructions]', kind: 'compact' },
   { name: '/quit', description: 'Exit the TUI', kind: 'quit' },
 ]