Using gpt-oss:20b in OpenCode with a larger context and high reasoning

I have hundreds of private journal entries stored locally, many with incorrect date formats. The correct date is in the filename, so I wanted to use an LLM to batch update them. However, I do not want to share my private journal with any third-party service. Instead, I used Ollama with gpt-oss:20b and OpenCode to do this all locally. The naive solution of just using gpt-oss:20b with Ollama&rsquo;s…