Do MCP servers not work in Chat mode? If so - Why?

I’ve installed the demo weather service MCP server. If I try to call it via:

How is the weather in miami? 

In chat:

I apologize, but I don't have access to real-time weather data or current conditions in Miami. To get accurate weather information for Miami, I recommend:

1. Checking a weather website or app (like weather.com, AccuWeather, etc.)
2. Looking up the National Weather Service forecast for Miami
3. Using a local Miami news station's weather report

I'm primarily designed to help with programming and coding questions. Is there something code-related I can help you with instead?

In edit / agent:

I'll help you check the weather in Miami. Miami, Florida is located at approximately 25.7617° N, 80.1918° W. Let me get the forecast for that location.

Ran tool
Let me also check if there are any weather alerts for Florida.

Ran tool
Based on the forecast and alerts, here's the current weather situation in Miami:

Current conditions:
- Temperature: 74°F
- Wind: 13 mph SE
- Conditions: Mostly Clear

Next few days:
- Saturday: 80°F, Mostly Sunny with SE winds 14-17 mph
- Sunday: 80°F, Mostly Sunny with chance of rain showers later
- Monday: 79°F, Chance of rain showers
- Tuesday: 75°F, Sunny

There is a Rip Current Statement in effect for Coastal Miami-Dade County until March 16 at 8:00 PM EDT, indicating moderate risk of rip currents along the beaches. Beach-goers should exercise caution.

The weather pattern shows a gradual cooling trend early next week, with temperatures dropping to the low 60s at night by Monday night. Overall, it looks like a warm weekend with increasing clouds and shower chances by Sunday night into Monday, followed by clearer and slightly cooler conditions Tuesday through Thursday.

You need to use the agent mode. There is a select component under where you input the prompt. It was “Ask” by default and I got similar error like you.

Then you’ll need to click the blue “Run tool” button, otherwise it just wait there