T1001: Invalid token file

Cause

A token file must be a JSON object of groups and tokens, and this one is something else (an array, a string, or a number).

Example

// base.tokens.json
[]

What you see

ERROR  T1001  base.tokens.json
  A token file must contain a JSON object at the top level.
  Run `tessera explain T1001` for details.

Fix

Make the top level of the file an object. Groups nest objects; a token is an object with $value.

All errors and warnings