lazy load mcp, limit history

web/agent/src/agent.py

@@ -23,9 +23,26 @@ logger.info(f"Initializing Cavepedia agent with CAVE_MCP_URL={CAVE_MCP_URL}")
 
 
 def limit_history(ctx: RunContext[None], messages: list[ModelMessage]) -> list[ModelMessage]:
-    """Limit conversation history to manage token usage and request size."""
-    # Keep only the last few messages to avoid large requests hitting Cloudflare limits
-    return messages[-4:]
+    """Limit history and clean up orphaned tool calls to prevent API errors."""
+    from pydantic_ai.messages import ModelResponse, ToolCallPart
+
+    if not messages:
+        return messages
+
+    # Keep only the last 4 messages
+    messages = messages[-4:]
+
+    # Check if the last message is an assistant response with a tool call
+    # If so, remove it - it's orphaned (no tool result followed)
+    if messages:
+        last_msg = messages[-1]
+        if isinstance(last_msg, ModelResponse):
+            has_tool_call = any(isinstance(part, ToolCallPart) for part in last_msg.parts)
+            if has_tool_call:
+                logger.warning("Removing orphaned tool call from history")
+                return messages[:-1]
+
+    return messages
 
 def check_mcp_available(url: str, timeout: float = 5.0) -> bool:
     """Check if MCP server is reachable via health endpoint."""
@@ -42,9 +59,7 @@ def check_mcp_available(url: str, timeout: float = 5.0) -> bool:
         logger.warning(f"MCP server not reachable: {e}")
         return False
 
-# Check if MCP is available at startup
-MCP_AVAILABLE = check_mcp_available(CAVE_MCP_URL)
-logger.info(f"MCP server available: {MCP_AVAILABLE}")
+# MCP availability is checked lazily in create_agent()
 
 AGENT_INSTRUCTIONS = """Caving assistant. Help with exploration, safety, surveying, locations, geology, equipment, history, conservation.
 
@@ -62,7 +77,10 @@ def create_agent(user_roles: list[str] | None = None):
     """Create an agent with MCP tools configured for the given user roles."""
     toolsets = []
 
-    if MCP_AVAILABLE and user_roles:
+    # Check MCP availability lazily (each request) to handle startup race conditions
+    mcp_available = check_mcp_available(CAVE_MCP_URL) if user_roles else False
+
+    if mcp_available and user_roles:
         try:
             import json
             from pydantic_ai.mcp import MCPServerStreamableHTTP
@@ -93,7 +111,4 @@ def create_agent(user_roles: list[str] | None = None):
     )
 
 
-# Create a default agent for health checks etc
-agent = create_agent()
-
 logger.info("Agent module initialized successfully")