00:01 Seed S-absent
00:20 Settings > General > New threads > Model. Row: "GPT-6-Astra · Medium"
00:23 settings.json defaultModelSelection = {"instanceId":"claude_work","model":"claude-opus-4-8","options":[{"id":"effort","value":"high"}]}
00:26 Open the effort picker (currently "Medium")
00:29 Choose Low
00:32 Picked Low. settings.json now {"instanceId":"codex","model":"gpt-6-astra","options":[{"id":"reasoningEffort","value":"low"},{"id":"serviceTier","value":"default"}]}
00:34 Reload the page
00:47 After reload. Row: "GPT-6-Astra · Low"
00:50 jq .defaultModelSelection settings.json -> {"instanceId":"codex","model":"gpt-6-astra","options":[{"id":"reasoningEffort","value":"low"},{"id":"serviceTier","value":"default"}]}