Forked subagents now inherit the prompt cache, and the todo tools are gone on newer models

Two releases landed after this feed last covered the changelog at 2.1.224. In 2.1.232, "subagent forking is now on by default", and a forked subagent "inherits the full conversation and prompt cache". Non-teammate agent spawns in interactive sessions now run in the background by default. The same release adds /config rows for cross-session inbound message handling, GitLab token redaction across nine prefix families, and GitLab plugin marketplaces.

2.1.233, dated today, removes something people build on: "Todo/task-tracking tools (TaskCreate/Get/Update/List, TodoWrite) are no longer available on Opus 4.8, Sonnet 5, Fable 5, Mythos 5, and newer models", restorable with CLAUDE_CODE_ENABLE_TODO_TOOLS=1. It also adds an opt-in memory cgroup for Bash commands on Linux (CLAUDE_CODE_TOOL_MEMORY_LIMIT) so "a runaway build can't stall the session", and a configurable WebFetch URL cache TTL (CLAUDE_CODE_WEBFETCH_CACHE_TTL_MS, default unchanged at 15 minutes).

Why it matters: Cache inheritance on fork is the direct counterweight to item 1. Until now a subagent paid for its own prefix from scratch, which is why the guidance has been to use one only when the job produces output you do not want to keep. A fork that arrives with the conversation and the cache already paid for changes that arithmetic, and it is on by default, so it changes for people who did not opt in. The todo-tool removal cuts the other way: if your harness or your prompts assume TodoWrite exists on a current model, they stopped working on upgrade, and the environment variable is the migration path rather than the fix.