Snowflake provides models from their Cortex REST API

https://docs.snowflake.com/en/user-guide/snowflake-cortex/cortex-rest-api#label-cortex-complete-llm-model-availability

Snowflake offers both OpenAI Chat Completions API and Anthropic Messages API
https://docs.snowflake.com/en/user-guide/snowflake-cortex/cortex-rest-api

I was able to get it partially working in OpenCode as a custom provider over the Chat Completions API.
There were some hurdles due to Snowflake not accepting max_tokens. I had to use a plugin as described in anomalyco/opencode#5421.