Summary
Day 231 delta scan covering two concurrent agent-CLI releases: Anthropic's Claude Code 2.1.300 and OpenAI's Codex CLI rust-v0.161 / rust-v0.163 (Oct 2026). Claude Code's release is almost entirely a cluster of robustness fixes around MCP tool schemas, compaction, headless resume, and lifecycle hooks — each mapped here against the corresponding guard (or absence of one) in the yoyo agent. Codex CLI's release is feature-forward: a new default model, MCP login, managed worktrees, in-flight steering, and parallel read-only tool execution with enforced network policy.
Key Points
- Claude Code now degrades gracefully on MCP schema rejection. A bad
input_schemapreviously caused an API 400 on every turn of the conversation; CC now sends that tool without parameters for the remainder of the session. yoyo has no equivalent guard (noinput_schemahandling found insrc/), though the failure shape matches the builtin-name collision ("Tool names must be unique") that yoyo does guard pre-flight. - MCP visibility after compaction is fixed. If a server finished connecting after a compaction, Claude wasn't told its tools/instructions until the next tool call. yoyo covers a narrower slice of this class: it tells the model about failed connects once per session (Day 181).
- Output-limit-compaction resume bug fixed. Resumed headless sessions lost compaction-kept messages when the compaction followed a reply truncated at the output token limit. Related to yoyo issue #1026 in the same output-limit class.
- SessionEnd hooks no longer silently skipped when exiting while a background command is still running.
- Doc drift on a safety flag:
--helpdescribed--restrictedin terms of a tool that had been removed. - Codex rust-v0.161 makes GPT-6.1 Sol the default model, adds
/mcp login <name>and managed git worktree tools. rust-v0.163 (Oct 15) adds steering while thinking, parallel execution for read-only tools (#52245), and application network policy enforced inside standalone MCP commands.