Thread sections and MCP 2026 open the next alpha

The new alpha line starts by expanding thread organization. Persistent sections replace the single pinned flag, add a stable Pinned section, and give app-server clients paginated listing and filtering for sectioned and unsectioned conversations.

MCP receives the largest protocol change. Codex can opt in to the 2026-07-28 lifecycle for modern discovery, paginated catalogs, multi-round calls, elicitation state, and bounded HTTP, SSE, and stdio messages while retaining legacy initialization and targeted fallback.

Unrelated optional MCP servers get a shared one-second startup grace instead of blocking the first model request. Tool catalogs resolve across servers concurrently, and servers that become ready during capture replace cached definitions with live bindings.

MCP OAuth now uses the configured route-aware client across CLI login, plugin installation, and skill dependencies. Plugin summaries also expose plan eligibility, disabled reasons, and installation time, while recommendations can be loaded independently from the installation-suggestion tool.

Deferred environments propagate more current state. Model context identifies the primary environment, readiness roots update in place, MCP file uploads use the current step snapshot, and subagents inherit environments that became ready before they were spawned.

Nested Codex requests carry parent-turn provenance, and supported collaboration messages can remain structured plaintext while their arguments stay redacted from logs. Remote exec and side-conversation cleanup can also drain in the background.

Release context: the rust-v0.146.0-alpha.14 to rust-v0.147.0-alpha.1 comparison contains 49 commits. GitHub's comparison response reaches its 300-file listing cap, so this post does not claim that 300 is the complete changed-file count.

Evidence