Migrate
From Anthropic
Point an Anthropic Messages client at plaingateway.
Set the Anthropic API root to https://plaingateway.com/api when the client appends /v1/messages.
Set its authentication token to a plaingateway key.
Use a catalog model ID such as anthropic/claude-haiku-5.5.
The Messages API keeps Anthropic-shaped responses and errors.
See the Claude Code example for its exact variables.