I’m working on an MCP server. ChatGPT requires implementing two tools, search and fetch, to install the MCP server. If I don’t have those two tools, I get an error when adding the connection.
The main issue is that when I try to use my MCP server, ChatGPT will only ever use the search tool. I have a few more tools implemented, I can see them when I query tools/list separately. But regardless of how I’m interacting with ChatGPT, it will only use the search tool.
I’ve tried wording my questions to get ChatGPT to use specific tools, but it only ever uses the search tool and just modifies the search query. I’ve also tried using GPT-5 in various modes, and using GPT-4, but having the same issue.
One thing is I can’t see the specific tools ChatGPT has identified from my MCP server, they aren’t listed anywhere in the Connections settings. So I can’t verify that ChatGPT sees my other tools.
Tool selection is super sensitive to the tool name and the tool descriptions. So if the search tool has a really generic name, it may “catch” all the calls that would go to the others. try marking the “search” description with “do not use this tool” to see if that forces it to use others. Remember, the tool name and description are both important. Make sure it is clear when to use the other tools based on the tool names and descriptions alone, not the parameters.
if it can’t figure out the parameter values for other tools, it won;’t try to use them. Try marking parameters optional or clarifying what the parameters do and how to fill them in when its not sure.
try asking it to list the tools it has available and see if it is aware of all the tools you are providing. Ask about specific parameters to see what it knows.
ask why its not using specific tools and ask it directly to call one of them. If it won’t, ask it to explain why WITHOUT calling the tool… this last point is important to “escape” the tool calling behavior and get it to reflect on its reasoning.
After some more investigation, it’s not seeing anything other than the search tool, or at least that is what it is telling me. It seems like the MCP Client in ChatGPT is only returning the search tool schema and nothing else. I’ve asked it multiple times and in multiple ways if it can see the other tools I know are returned from tools/list.
I know the fetch tool also exists because I can’t connect to my MCP server without search and fetch both being available. So at least when it calls tools/list initially it sees both tools. And I’ve seen it use the fetch tool when I request more information about an item returned from search. Even when I ask specifically about the fetch tool, it says it doesn’t have access to it.
I don’t see any way to look at any logs or errors regarding my MCP server either.
I’m not. I know developer mode exists now but I don’t see it as an option for me. I’ll check with our admins to see if there is a setting they need to configure
I’m assuming you had the same issue I did. Developer mode for a Plus (individual account, not a Teams one right?) requires developer mode, but since developer mode does not exist in a Team’s setting, you can’t get it to work with custom tools.
What’s really strange, is that if you go to the connector settings, open your network tab, hit refresh, you’ll see that it actually finds all of the custom tools.
It just seems to be gated behind developer mode, which kind of defeats the whole purpose of custom connectors, especially in a Teams environment.
The documentation really does read like it SHOULD work, as long as you support search and fetch - and all developer mode is supposed to do is allow you to not provide those.
