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MCP lucid_create_diagram_from_specification tool size issue

  • June 1, 2026
  • 6 replies
  • 145 views

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Error POSTing to endpoint (HTTP 400): Request body too large (max 53KB). JSON-RPC error code: -32602.

Best answer by aishakhan

Hi ​@Umansh Sarabhai,

 

Our Development Team has released a change for this. Can you please let me know if the issue persists?

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  • Lucid support team
  • June 15, 2026

Hi ​@Umansh Sarabhai,

 

Thank you for posting in the Lucid Community! To get a better idea of the issue you are running into can you please provide the following information: 

  • Did this occur on a Lucidchart or Lucidspark board? 
  • Which MCP client (LLM) are you using?
  • Any screenshots of the flow when reproducing this error.

I appreciate your help looking into this further.


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I am using Lucid’s official MCP with Cursor

https://mcp.lucid.app/mcp


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  • Lucid support team
  • June 17, 2026

Hi ​@Umansh Sarabhai,

 

Thanks for letting me know. Can you confirm if this occurs on a Lucidchart or Lucidspark board? Do you have any screenshots of the flow you are taking when reproducing the error?
 


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This occured on lucidchart. Attached the diagram above which was casuing the issue.


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  • Lucid support team
  • June 22, 2026

Hi ​@Umansh Sarabhai,

 

It doesn’t look like the diagram was attached successfully. Can you share a temporary Document Support PIN for this document? This PIN is safe to post in this thread because it is only accessible by members of the Lucid support staff. You can find steps for generating a Support PIN in this Lucid Help Center article: Generate a Lucid Support PIN.


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  • Lucid support team
  • Answer
  • June 23, 2026

Hi ​@Umansh Sarabhai,

 

Our Development Team has released a change for this. Can you please let me know if the issue persists?