When clearing temperature or topP on an existing agent, the UI sent undefined which JSON.stringify drops, so the server never received the clear command. Now sends null to properly remove the override in opencode.json. Changed updateAgent to use 'field' in config pattern for temperature and top_p, matching the existing prompt handling. Co-authored-by: Leonid Skorobogatyy <bash@opencode.itc.local> Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>