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Public story · 2026-08-19 · high
CLAUDE_CODE_ENABLE_TODO_TOOLS=1 fixes the August 15 removal from Opus 4.8, Sonnet 5, Fable 5, and Mythos 5+, but nothing flags skills that need it.
Why now: code.claude.com's changelog through 2.1.235 confirms the fix, closing out a week of environment-variable changes covered here since August 15.
CLAUDE_CODE_ENABLE_TODO_TOOLS=1 restores the todo tool pulled from Opus 4.8, Sonnet 5, Fable 5, and Mythos 5+ on August 15, per Claude Code's changelog through 2.1.235.
That removal broke anything relying on the model to track multi-step work through a dedicated tool. The fix is one environment variable, but nothing signals when you need it.
Other changes landed in the same window. Bash got memory cgroups on August 15. WebFetch picked up a cache TTL and a forward_user_identity flag on August 17. Per-project config directories and quota-reset auto-resume landed on August 18. Those are additions, not removals, so the changelog doesn't say they carry the same failure risk.
The todo removal is the one that bites without warning. If a skill or prompt still references a todo or task tool, it won't throw an error. The model just stops tracking steps the way the skill expects, and it reads like the model lost the thread on its own.
Grep your skill files for todo or task tool references before you blame the model for dropping a long task. If you find one, set CLAUDE_CODE_ENABLE_TODO_TOOLS=1 and rerun it.
Each link below shares sources, entities, or timing with this story.
Claude Code uses WebFetch / Shared entities / Same source / Shared topic / Earlier coverage
Linked by a graph relationship (Claude Code uses WebFetch); both cover Claude Code, TTL, WebFetch; cite the same source (code.claude.com).
Claude Code uses WebFetch / Shared entities / Shared topic / Earlier coverage
Linked by a graph relationship (Claude Code uses WebFetch); both cover Claude Code, Fable, Mythos, Opus; overlapping topics (claude, todo).
Claude Code uses WebFetch / Shared entities / Earlier coverage / Tension
Linked by a graph relationship (Claude Code uses WebFetch); both cover Claude Code, Fable, Grep, Mythos; earlier Claude Code coverage from 2026-06-14.
Claude Code uses WebFetch / Shared entities / Shared topic / Earlier coverage / Tension
Linked by a graph relationship (Claude Code uses WebFetch); both cover Claude Code, Fable, Mythos, Opus; overlapping topics (been, claude).
Claude Code uses WebFetch / Shared entities / Same source / Shared topic / Earlier coverage / Tension
Linked by a graph relationship (Claude Code uses WebFetch); both cover Claude Code, Opus; cite the same source (code.claude.com).
Claude Code uses WebFetch / Shared entities / Shared topic / Earlier coverage
Linked by a graph relationship (Claude Code uses WebFetch); both cover Claude Code, Fable, Opus, TTL; overlapping topics (cache, claude).
Claude Code uses WebFetch / Shared entities / Same source / Shared topic / Earlier coverage
Linked by a graph relationship (Claude Code uses WebFetch); both cover Bash, Claude Code; cite the same source (code.claude.com).
Linked by a graph relationship (Claude Code uses WebFetch); both cover Bash, Claude Code; cite the same source (code.claude.com).