List datasource not working as expected

[orathee]

I connected my chat app to tableau mcp and langsmith for traceability.

On our tableau cloud site we have around 100 published data sources. In environment file i have restricted datasources to only 2 with luid.

When asked which datasources he has access to, it should list the datasources. But chatbot return I don't have access to any datasource. But when i tell the exact name of datasource then chatbot agree that he has access to datasource and then return answers based on datasource.

I checked in Langsmith and it show, the set of allowed data sources that can be queried is limited by the server configuration. While data sources were found, they were all filtered out by the server configuration.

I believe it is happening due to pagination limit. list-datasources tool first select top N/10 datasources and try to find the datasources in that list. Sometime those two datasources appear in Top 10 and it return those 2 datasources but sometimes they are out of Top N/10 due to random sort order of Top N.

[anyoung-tableau]

Have you defined a value of MAX_RESULT_LIMIT or MAX_RESULT_LIMITS?

If so, and the List Datasources REST API returns more than the limit, the remaining are chopped off, and then the datasource luid restriction is applied.

If you remove the max result limit, does the issue go away?

[orathee]

Initially there was no limit and this variable was not in env file. Then also I was facing this issue. After assigning value of 100 then facing same issue. In langsmith i see this pageSize: 20 limit: 20 . However i added the project and datasource id variables along with MAX_RESULT_LIMITS=list-datasources:100 but still in langsmith limit is showing 20.

As of now, I am handling this in my app like below

if _tool.name == "list-datasources":
cleaned_kwargs["pageSize"] = 100
cleaned_kwargs["limit"] = 100

[anyoung-tableau]

Why is langsmith providing the limit argument at all? Consider removing it so the tool relies entirely on MAX_RESULT_LIMITS since the tool will take the smaller of limit and MAX_RESULT_LIMITS and chop the remainder off.

[orathee]

Does that mean limit parameter is applied by llm and it doesn't have anything related to list-datasources tool ? If yer, then i am not sure how langsmith adding it all

[anyoung-tableau]

limit is a parameter of the list-datasources tool that can be provided by the LLM when it calls the tool based on the prompt; take a look at its definition.

If the limit parameter is provided, the set of datasources returned by the list-datasources tool will contain at most the minimum of limit and whatever is set on the MAX_RESULT_LIMIT or MAX_RESULT_LIMITS environment variables.