feat: add /compact command to compress conversation history

Add /compact command that uses LLM to intelligently summarize and
compress conversation history while preserving key context like
decisions, code changes, and technical details.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: lzwjava

iclaw/commands/compact.py

@@ -0,0 +1,48 @@
+"""Handle /compact command to compress conversation history using LLM."""
+
+
+def handle_compact_command(messages, chat_fn, copilot_token, current_model):
+    """Compress conversation history using LLM to summarize context."""
+    if not messages:
+        print("No conversation history to compact.")
+        return messages
+
+    prompt = """Summarize the conversation history below into a concise context summary that preserves:
+1. Key decisions and outcomes
+2. Important code changes or file references
+3. Current task or goal
+4. Critical technical details
+
+Be extremely concise. Output only the summary, no preamble.
+
+Conversation history:
+"""
+
+    history_text = ""
+    for msg in messages:
+        role = msg.get("role", "")
+        content = msg.get("content", "")
+        if content:
+            history_text += f"{role}: {content}\n\n"
+
+    compact_messages = [{"role": "user", "content": prompt + history_text}]
+
+    try:
+        response = chat_fn(compact_messages, copilot_token, current_model, tools=None)
+        summary = response.get("content", "")
+
+        if summary:
+            new_messages = [
+                {
+                    "role": "system",
+                    "content": f"Previous conversation summary:\n{summary}",
+                }
+            ]
+            print(f"Compacted {len(messages)} messages into summary.")
+            return new_messages
+        else:
+            print("Failed to compact: no summary generated.")
+            return messages
+    except Exception as e:
+        print(f"Error compacting history: {e}")
+        return messages

iclaw/completer.py

@@ -15,6 +15,7 @@
     "/status",
     "/help",
     "/clear",
+    "/compact",
     ".exit",
 ]
 

iclaw/main.py

@@ -9,6 +9,7 @@
 from iclaw import http
 from iclaw import log
 from iclaw.at_mention import resolve_at_mentions
+from iclaw.commands.compact import handle_compact_command
 from iclaw.commands.log import handle_log_command
 from iclaw.commands.model import handle_model_command, handle_model_provider_command
 from iclaw.commands.proxy import handle_ca_bundle_command, handle_proxy_command
@@ -38,6 +39,7 @@
     ("/log", "Set log verbosity (usage: /log [verbose|info])"),
     ("/copy", "Copy last Copilot response to clipboard"),
     ("/clear", "Clear conversation history"),
+    ("/compact", "Compact conversation history using LLM"),
     ("/status", "Show current settings"),
     ("/help", "Show available commands"),
     (".exit", "Quit"),
@@ -222,6 +224,11 @@ def main():
             last_reply = None
             print("Conversation history cleared.")
             continue
+        if user_input == "/compact":
+            messages = handle_compact_command(
+                messages, chat, copilot_token, current_model
+            )
+            continue
 
         if not copilot_token:
             print("Not authenticated. Type /provider_model first.", file=sys.stderr)