diff --git a/src/autocoder/__init__.py b/src/autocoder/__init__.py
index c148dc05..5dcfb3ab 100644
--- a/src/autocoder/__init__.py
+++ b/src/autocoder/__init__.py
@@ -4,20 +4,31 @@
 A powerful autonomous coding system with parallel agents, web UI, and MCP tools.
 """
 
-__version__ = "0.1.0"
+from __future__ import annotations
+
+import importlib
+from typing import TYPE_CHECKING, Any
 
-# Core system exports
-from autocoder.core.orchestrator import Orchestrator, create_orchestrator
-from autocoder.core.gatekeeper import Gatekeeper
-from autocoder.core.worktree_manager import WorktreeManager
-from autocoder.core.knowledge_base import KnowledgeBase, get_knowledge_base
-from autocoder.core.model_settings import ModelSettings, ModelPreset, get_full_model_id
-from autocoder.core.test_framework_detector import TestFrameworkDetector
-from autocoder.core.database import Database, get_database
+__version__ = "0.1.0"
 
-# Agent exports
-from autocoder.agent.agent import run_autonomous_agent
-from autocoder.agent.client import ClaudeSDKClient
+_LAZY_EXPORTS: dict[str, tuple[str, str]] = {
+    # Core system
+    "Orchestrator": ("autocoder.core.orchestrator", "Orchestrator"),
+    "create_orchestrator": ("autocoder.core.orchestrator", "create_orchestrator"),
+    "Gatekeeper": ("autocoder.core.gatekeeper", "Gatekeeper"),
+    "WorktreeManager": ("autocoder.core.worktree_manager", "WorktreeManager"),
+    "KnowledgeBase": ("autocoder.core.knowledge_base", "KnowledgeBase"),
+    "get_knowledge_base": ("autocoder.core.knowledge_base", "get_knowledge_base"),
+    "ModelSettings": ("autocoder.core.model_settings", "ModelSettings"),
+    "ModelPreset": ("autocoder.core.model_settings", "ModelPreset"),
+    "get_full_model_id": ("autocoder.core.model_settings", "get_full_model_id"),
+    "TestFrameworkDetector": ("autocoder.core.test_framework_detector", "TestFrameworkDetector"),
+    "Database": ("autocoder.core.database", "Database"),
+    "get_database": ("autocoder.core.database", "get_database"),
+    # Agent
+    "run_autonomous_agent": ("autocoder.agent.agent", "run_autonomous_agent"),
+    "ClaudeSDKClient": ("autocoder.agent.client", "ClaudeSDKClient"),
+}
 
 __all__ = [
     # Core system
@@ -37,3 +48,37 @@
     "run_autonomous_agent",
     "ClaudeSDKClient",
 ]
+
+if TYPE_CHECKING:
+    from autocoder.agent.agent import run_autonomous_agent as run_autonomous_agent
+    from autocoder.agent.client import ClaudeSDKClient as ClaudeSDKClient
+    from autocoder.core.database import Database as Database
+    from autocoder.core.database import get_database as get_database
+    from autocoder.core.gatekeeper import Gatekeeper as Gatekeeper
+    from autocoder.core.knowledge_base import KnowledgeBase as KnowledgeBase
+    from autocoder.core.knowledge_base import get_knowledge_base as get_knowledge_base
+    from autocoder.core.model_settings import ModelPreset as ModelPreset
+    from autocoder.core.model_settings import ModelSettings as ModelSettings
+    from autocoder.core.model_settings import get_full_model_id as get_full_model_id
+    from autocoder.core.orchestrator import Orchestrator as Orchestrator
+    from autocoder.core.orchestrator import create_orchestrator as create_orchestrator
+    from autocoder.core.test_framework_detector import (
+        TestFrameworkDetector as TestFrameworkDetector,
+    )
+    from autocoder.core.worktree_manager import WorktreeManager as WorktreeManager
+
+
+def __getattr__(name: str) -> Any:
+    spec = _LAZY_EXPORTS.get(name)
+    if not spec:
+        raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
+
+    module_name, attr_name = spec
+    module = importlib.import_module(module_name)
+    value = getattr(module, attr_name)
+    globals()[name] = value  # Cache for future access
+    return value
+
+
+def __dir__() -> list[str]:
+    return sorted(list(globals().keys()) + list(_LAZY_EXPORTS.keys()))
diff --git a/src/autocoder/core/__init__.py b/src/autocoder/core/__init__.py
index e96dd962..7044d068 100644
--- a/src/autocoder/core/__init__.py
+++ b/src/autocoder/core/__init__.py
@@ -11,13 +11,25 @@
 - Database: SQLite database wrapper
 """
 
-from autocoder.core.orchestrator import Orchestrator, create_orchestrator
-from autocoder.core.gatekeeper import Gatekeeper
-from autocoder.core.worktree_manager import WorktreeManager
-from autocoder.core.knowledge_base import KnowledgeBase, get_knowledge_base
-from autocoder.core.model_settings import ModelSettings, ModelPreset, get_full_model_id
-from autocoder.core.test_framework_detector import TestFrameworkDetector
-from autocoder.core.database import Database, get_database
+from __future__ import annotations
+
+import importlib
+from typing import TYPE_CHECKING, Any
+
+_LAZY_EXPORTS: dict[str, tuple[str, str]] = {
+    "Orchestrator": ("autocoder.core.orchestrator", "Orchestrator"),
+    "create_orchestrator": ("autocoder.core.orchestrator", "create_orchestrator"),
+    "Gatekeeper": ("autocoder.core.gatekeeper", "Gatekeeper"),
+    "WorktreeManager": ("autocoder.core.worktree_manager", "WorktreeManager"),
+    "KnowledgeBase": ("autocoder.core.knowledge_base", "KnowledgeBase"),
+    "get_knowledge_base": ("autocoder.core.knowledge_base", "get_knowledge_base"),
+    "ModelSettings": ("autocoder.core.model_settings", "ModelSettings"),
+    "ModelPreset": ("autocoder.core.model_settings", "ModelPreset"),
+    "get_full_model_id": ("autocoder.core.model_settings", "get_full_model_id"),
+    "TestFrameworkDetector": ("autocoder.core.test_framework_detector", "TestFrameworkDetector"),
+    "Database": ("autocoder.core.database", "Database"),
+    "get_database": ("autocoder.core.database", "get_database"),
+}
 
 __all__ = [
     "Orchestrator",
@@ -33,3 +45,35 @@
     "Database",
     "get_database",
 ]
+
+if TYPE_CHECKING:
+    from autocoder.core.database import Database as Database
+    from autocoder.core.database import get_database as get_database
+    from autocoder.core.gatekeeper import Gatekeeper as Gatekeeper
+    from autocoder.core.knowledge_base import KnowledgeBase as KnowledgeBase
+    from autocoder.core.knowledge_base import get_knowledge_base as get_knowledge_base
+    from autocoder.core.model_settings import ModelPreset as ModelPreset
+    from autocoder.core.model_settings import ModelSettings as ModelSettings
+    from autocoder.core.model_settings import get_full_model_id as get_full_model_id
+    from autocoder.core.orchestrator import Orchestrator as Orchestrator
+    from autocoder.core.orchestrator import create_orchestrator as create_orchestrator
+    from autocoder.core.test_framework_detector import (
+        TestFrameworkDetector as TestFrameworkDetector,
+    )
+    from autocoder.core.worktree_manager import WorktreeManager as WorktreeManager
+
+
+def __getattr__(name: str) -> Any:
+    spec = _LAZY_EXPORTS.get(name)
+    if not spec:
+        raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
+
+    module_name, attr_name = spec
+    module = importlib.import_module(module_name)
+    value = getattr(module, attr_name)
+    globals()[name] = value  # Cache for future access
+    return value
+
+
+def __dir__() -> list[str]:
+    return sorted(list(globals().keys()) + list(_LAZY_EXPORTS.keys()))
diff --git a/ui/src/lib/api.ts b/ui/src/lib/api.ts
index 41f27d69..bed9f4a4 100644
--- a/ui/src/lib/api.ts
+++ b/ui/src/lib/api.ts
@@ -61,10 +61,19 @@ async function fetchJSON<T>(url: string, options?: RequestInit): Promise<T> {
   if (!response.ok) {
     const payload = await response.json().catch(() => ({ detail: 'Unknown error' }))
     const detail = (payload as any)?.detail ?? payload
+    const detailMessage =
+      detail &&
+      typeof detail === 'object' &&
+      typeof (detail as any)?.message === 'string' &&
+      (detail as any).message.trim()
+        ? String((detail as any).message)
+        : null
     const message =
       typeof detail === 'string'
         ? detail
-        : typeof (payload as any)?.message === 'string'
+        : detailMessage
+          ? detailMessage
+          : typeof (payload as any)?.message === 'string'
           ? (payload as any).message
           : JSON.stringify(detail, null, 2)