Getting issue in n8n MCP Client node (1.107.2)

[makani20]

{ "errorMessage": "Bad request - please check your parameters", "errorDescription": "Invalid schema for function 'wc_add_product': In context=('properties', 'meta_data', 'items', 'properties', 'value', 'anyOf', '6'), array schema missing items.", "errorDetails": {}, "n8nDetails": { "time": "8/18/2025, 11:26:28 AM", "n8nVersion": "1.106.3 (Self Hosted)", "binaryDataMode": "default" } }

[salahmasllouhi]

hello, did you get any solution for this error ?

[Fercan10d]

Same error

[galatanovidiu]

This appears to be an invalid JSON Schema in the wc_add_product ability definition rather than an mcp-adapter bug.

Somewhere in the ability's input_schema, there's an array type definition that's missing the required items property.

The mcp-adapter passes the input_schema from WordPress abilities directly to MCP tools, so invalid schemas in ability definitions are exposed to MCP clients such as n8n.

---

Please share the wc_add_product ability code, so I can perform a deeper analysis and pinpoint the exact location of the schema issue.