Claude Code drops Opus 4.8 Fast mode Nov 30 — move to Opus 5.5
After Nov 30, Fast requests error instead of falling back to standard Opus 4.8. Opus 5.5 Fast is the drop-in; Codex's CLI gains queue-resume and diagnostics.
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Opus 4.8 Fast mode is on the clock
Claude Code's newest build (v2.1.316, Oct 31) marks Opus 4.8 Fast mode deprecated as of Oct 30 and scheduled for removal Nov 30. After that date, requests that ask for Fast error out instead of silently falling back to standard Opus 4.8 — so any scripted `/fast` runs or fast-mode beta headers pinned to 4.8 will start failing.
Opus 5.5 Fast is the drop-in
Anthropic points the migration at Opus 5.5, whose Fast mode already left research preview — no access request, and the beta header is now optional (requests that still send it keep working). A default Fast rate limit applies on the Start, Build, and Scale tiers, so check your tier's ceiling before you cut over.
Codex 0.166 adds queue-resume and a network doctor
OpenAI's Codex CLI (v0.166.0) lets you `codex queue --resume` to pick threads back up after queuing a message, adds `codex doctor --network-only` for focused connectivity and WebSocket checks, and wires GPT-6.1 Terra into the bundled, Vertex, and Bedrock model catalogs.