Codex CLI: Persistent JavaScript Runtime & Live Connection Upgrades
CodexCodex CLI 0.100.0 landed on February 12, 2026 as a major feature release, introducing an experimental JavaScript REPL runtime with persistent state, support for multiple simultaneous rate limits, and reintroduction of the app-server websocket transport. The update also adds memory management slash commands, expands sandbox capabilities on both Linux and Windows, and resolves a set of session stability and reliability bugs.
Sources & Mentions
3 external resources covering this update
Overview
Version 0.100.0 of the Codex CLI is one of the larger feature releases in the tool's history, shipping on February 12, 2026 alongside the 0.101.0 patch and the GPT-5.3-Codex-Spark model announcement. It introduces experimental runtime capabilities, new protocol features, and expanded platform support.
New Features
Experimental JavaScript REPL Runtime
The release introduces an experimental, feature-gated JavaScript REPL runtime (js_repl) that can persist state across tool calls. Unlike a stateless code execution environment, this REPL maintains variable bindings and execution context between successive calls within a session, enabling iterative scripting workflows. An optional runtime path override is supported, and the feature ships with accompanying documentation and schema configuration guidance.
Multiple Simultaneous Rate Limits
Codex CLI 0.100.0 adds support for multiple simultaneous rate limits across the protocol layer, backend client, and TUI status surfaces. This allows the system to track and respect multiple concurrent quota signals — useful for enterprise deployments where different rate constraints may apply simultaneously across different API tiers or organizational policies.
App-Server Websocket Transport
The app-server websocket transport, previously removed, has been reintroduced with an upgraded split inbound/outbound architecture. The new implementation adds connection-aware thread resume subscriptions, improving reliability when the connection state changes mid-session.
Memory Management Slash Commands
Two new slash commands are available in the TUI: /m_update and /m_drop. These give users direct control over memory entries — updating or discarding specific items from the memory system without leaving the active session.
Expanded Sandbox Capabilities
Sandbox capabilities have been promoted on both Linux and Windows. A new ReadOnlyAccess policy shape has been introduced, giving operators configurable control over read access within sandboxed environments. This is relevant for security-conscious deployments where write access must be tightly scoped.
Bug Fixes
Several issues were resolved in this release:
- Websocket incremental output duplication and append prevention
- Session stability improvements via continued ping handling during idle periods
- Stale thread entries fixed by dropping missing rollout files
- Windows multi-line paste reliability improvements in terminals
- Corrected rate-limit inheritance during partial updates
- File-watcher debounce increased from 1 second to 10 seconds to reduce parse-error spam
Infrastructure
The codex-common crate was split into focused utility crates. Windows and musl build pipelines were improved, and GitHub release asset upload collision prevention was added.