# X_CLIENT_SPEC_UNSUPPORTED

## Means

x client met an OpenAPI construct its compiler refuses

## Typical cause

the source document uses a construct the compiler does not read (the cause names its JSON pointer): not, if/then/else, patternProperties, a non-JSON body, a cookie parameter

## Fix

`x help client --json` — then rerun with --only naming the tags around the pointer the cause names, or pin a corrected source.json

[CLI and verify](/error-codes#cli-and-verify)