feat(mcp): add preset setup and capability mentions

nanobot/session/manager.py

@@ -27,6 +27,8 @@ _MESSAGE_TIME_PREFIX_RE = re.compile(r"^\[Message Time: [^\]]+\]\n?")
 _LOCAL_IMAGE_BREADCRUMB_RE = re.compile(r"^\[image: (?:/|~)[^\]]+\]\s*$")
 _TOOL_CALL_ECHO_RE = re.compile(r'^\s*(?:generate_image|message)\([^)]*\)\s*$')
 _SESSION_PREVIEW_MAX_CHARS = 120
+_SESSION_LIST_PREVIEW_MAX_RECORDS = 200
+_SESSION_LIST_PREVIEW_MAX_CHARS = 1_000_000
 
 
 def _sanitize_assistant_replay_text(content: str) -> str:
@@ -182,6 +184,28 @@ class Session:
                 if cli_lines:
                     breadcrumbs = "\n".join(cli_lines)
                     content = f"{content}\n{breadcrumbs}" if content else breadcrumbs
+            mcp_presets = message.get("mcp_presets")
+            if (
+                role == "user"
+                and isinstance(mcp_presets, list)
+                and mcp_presets
+                and isinstance(content, str)
+            ):
+                mcp_lines: list[str] = []
+                for item in mcp_presets[:8]:
+                    if not isinstance(item, dict):
+                        continue
+                    name = str(item.get("name") or "").strip().lower()
+                    if not name:
+                        continue
+                    transport = str(item.get("transport") or "mcp").strip() or "mcp"
+                    mcp_lines.append(
+                        f"[MCP Preset Attachment: @{name}; tool_prefix=mcp_{name}_; "
+                        f"transport={transport}]"
+                    )
+                if mcp_lines:
+                    breadcrumbs = "\n".join(mcp_lines)
+                    content = f"{content}\n{breadcrumbs}" if content else breadcrumbs
             if include_timestamps:
                 content = self._annotate_message_time(message, content)
             if role == "assistant" and isinstance(content, str) and not content.strip():
@@ -621,9 +645,18 @@ class SessionManager:
                             title = metadata.get("title") if isinstance(metadata, dict) else None
                             preview = ""
                             fallback_preview = ""
+                            scanned_records = 0
+                            scanned_chars = 0
                             for line in f:
                                 if not line.strip():
                                     continue
+                                scanned_records += 1
+                                scanned_chars += len(line)
+                                if (
+                                    scanned_records > _SESSION_LIST_PREVIEW_MAX_RECORDS
+                                    or scanned_chars > _SESSION_LIST_PREVIEW_MAX_CHARS
+                                ):
+                                    break
                                 item = json.loads(line)
                                 if item.get("_type") == "metadata":
                                     continue