Codex CLI 0.147.0-alpha.4

• [changed] Agent input handling is expressed as send-input rather than write-stdin (same role, clearer naming).
• [changed] Collaboration/agent control surfaces are more explicit, including close, interrupt, and register-agent style operations plus collaboration-mode messaging.
• [changed] Hook configuration modeling is richer, including managed hooks requirements and clearer command vs prompt handler distinction.
• [changed] Account/login modeling around Amazon Bedrock and API key flows is refined.
• [changed] MCP-related identity and matching options are adjusted (including command timeout and regex-style value matching).
• [changed] Thread store configuration distinguishes in-memory vs local backends more cleanly.
• [changed] The MCP protoc-related environment variable is now CODEX_MCP_PROTOCC (replacing CODEX_MCP_PROTOC).
• [removed] Legacy client message/ack event types are dropped from the event surface as the wire protocol is simplified.
• [new] External-agent migration gains session append support for carrying sessions forward.

Under the hood

• Data models for config requirements, model defaults/messages, tool choice, and related API payloads were reshaped; several one-off migration/requirements structs were removed or folded in.
• OpenTelemetry exporter and web-search/action enums were adjusted as part of the same pass.
• The wildmatch dependency is no longer linked.
• Workspace version metadata is bumped to 0.147.0-alpha.4.

Upgrade notes

• If you set CODEX_MCP_PROTOC, switch to CODEX_MCP_PROTOCC.
• Anything still depending on write-stdin argument naming or the removed client ack/message events should move to the send-input and updated event APIs.