Claude Code Deleted the Todo List on Every Model After Opus 4.8
Version 2.1.233 removed five task-tracking tools from Opus 4.8, Sonnet 5, Fable 5, Mythos 5 and newer — and left an env var to put them back. The scaffolding you built for last year's model is now the thing slowing it down.
NeuroX AI · August 16, 2026
Claude Code 2.1.233 shipped a one-line deletion most teams will read past: TaskCreate, TaskGet, TaskUpdate, TaskList and TodoWrite are no longer available on Opus 4.8, Sonnet 5, Fable 5, Mythos 5, or anything newer. Five tools, gone from the top of the model line. Set CLAUDE_CODE_ENABLE_TODO_TOOLS=1 and they come back.
That escape hatch is the tell. This isn't a deprecation — nothing is broken and nothing was replaced. It's a default flip that says the checklist was worth its context cost on older models and isn't anymore. Every tool definition is tokens in the window and one more branch the model has to consider on every turn. A plan the model keeps in its head costs nothing; a plan it writes to a tool costs a call, a result, and a slice of attention, on every step.
The generalizable part has nothing to do with todo lists. Most in-house agent harnesses are scaffolding built against a specific model's weaknesses — forced reflection steps, re-read-the-file prompts, self-critique loops, retry wrappers around a tool the model used to fumble. That scaffolding was measured once, against a model you no longer run. Nobody re-measures it after an upgrade, because it isn't failing. It's just no longer paying for itself.
Upgrading the model is the cheap half. Deleting what it made obsolete is the work.