Expose Codex task lifecycle events to other VS Code extensions

What variant of Codex are you using?

IDE Extension (VS Code)

What feature would you like to see?

Summary

It would be very useful if the Codex VS Code extension exposed a stable, documented way for other VS Code extensions or local developer tooling to observe Codex task lifecycle events, especially when a task starts, completes, fails, or is aborted.

This request is not about notifications or sounds specifically. The broader need is integration with local developer workflows that depend on knowing when Codex has finished a turn or task.

Motivation

Many teams build local automation around their development workflow: documentation validators, review gates, CI preflight scripts, local dashboards, QA checklists, branch status monitors, and custom review tools.

Today, if a team wants to react when Codex finishes, the most reliable workaround is to ask the agent itself to run a command at the end of each turn. That works for some cases, but it is fragile because it depends on instruction-following rather than an explicit product-level integration point.

A first-class lifecycle API would make these workflows more reliable and composable.

Example use cases

• Trigger local post-task validation after Codex completes a turn.
• Update a local project dashboard showing active/completed Codex tasks.
• Integrate Codex task completion with internal review queues.
• Start CI preflight checks once Codex has stopped modifying files.
• Let other VS Code extensions react to Codex task status without scraping UI state or patching private internals.
• Improve accessibility and workflow feedback for long-running Codex tasks.
• Coordinate multi-step human review flows after a Codex task completes.

Proposed API

Expose a stable VS Code extension API from the Codex extension, for example:

export type CodexTaskStatus =
  | "started"
  | "completed"
  | "failed"
  | "aborted";

export interface CodexTaskLifecycleEvent {
  taskId: string;
  conversationId?: string;
  workspaceFolder?: string;
  status: CodexTaskStatus;
  timestamp: string;
  source: "local" | "cloud";
  errorMessage?: string;
}

export interface CodexExtensionApi {
  onDidChangeTaskStatus(
    listener: (event: CodexTaskLifecycleEvent) => void
  ): vscode.Disposable;
}

### Additional information

_No response_

No files, tests, or extension API entry point are identified in the issue. Start by locating the Codex VS Code extension's public API boundary and existing task-state handling, then clarify lifecycle semantics and compatibility requirements. Done means other extensions can reliably observe the documented task events without scraping UI state or using private internals.