Hello!
I'm trying to use the MCP server built into SQLcl v25.4.0.346.1855 with Claude Code v2.1.12. The MCP server worked a few months ago but after some updates / changes on Anthropic's side, I now get this error for any prompt if the server is active in my .claude.json:
API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"tools.21.custom.input_schema: JSON schema is invalid. It must match JSON
Schema draft 2020-12 (https://json-schema.org/draft/2020-12). Learn more about tool use at
https://docs.claude.com/en/docs/tool-use."},"request_id":"req_011CXH7YCx587zuASByLpHYJ"}
My .claude.json config looks like this:
"oracle": {
"command": "C:\\Oracle\\sqlcl\\bin\\sql",
"args": [
"-mcp"
]
}
This is the most relevant bug I could find on the Claude Code GitHub, it seems like Anthropic are now enforcing strict schema validation for MCP servers:
https://github.com/anthropics/claude-code/issues/10606
Has anyone else ran into this? The GitHub issue suggests downgrading to Claude Code v2.0.20, I've tried some older versions but the issue appears to be server-side (as the error message suggests)