Feature request: Add native Deep Research task mode in Codex Mac app and CLI

Feature Request

Codex should support a native Deep Research task mode in the Codex Mac app, and ideally in Codex CLI as well, that can be triggered from an active Codex session before implementation work begins.

This is not the same as selecting o3-deep-research, o4-mini-deep-research, or GPT-5.5 Pro as the normal development model in the model dropdown. The request is for a dedicated research workflow inside Codex, especially in the Mac app experience where users already manage long-running coding sessions and workspace context.

Problem

Codex has the best project context: current workspace files, git state, diffs, issues, docs, tests, terminal output, and task history. ChatGPT Deep Research has the best long-running research workflow. Today those are split.

When I need exhaustive research before implementation, I can use Deep Research in ChatGPT, but my ChatGPT project context is often stale relative to the active Codex workspace. The alternative is calling the Deep Research API separately from Codex, which requires extra API billing even though ChatGPT subscriptions already include Deep Research access.

This is especially painful in the Codex Mac app, because the app is where I can see and steer the current coding thread, local workspace, files, and running terminal context. That is exactly where a pre-implementation Deep Research button or command should live.

Desired Behavior

Add a native Codex Mac app command, composer action, or task mode, for example:

/deep-research <research question>

or a UI action like:

Run Deep Research before implementation

The same capability would also be useful in Codex CLI, but the Mac app should be treated as a first-class target surface, not an afterthought.

This mode should:

• gather live workspace context intentionally from the active Codex Mac app thread/worktree
• include relevant repo files, git state, diffs, linked GitHub issues/PRs, docs, tests, terminal/task state, and recent Codex context
• produce a research prompt pack instead of dumping the whole repo
• run a long-running research task using Deep Research models or GPT-5.5 Pro where available
• return a cited research report inside the Codex Mac app thread
• preserve source links to repo files, issues, commits, and external sources
• hand off the result back into the Codex thread for implementation planning
• show estimated cost / entitlement usage before starting
• support background execution and notification when the research finishes

Important Distinction

This is not asking for o3-deep-research or another Deep Research model to become a normal coding model in the dropdown.

The ask is a separate research lane in Codex:

live Codex Mac app workspace/thread context
-> research prompt/context pack
-> Deep Research / GPT-5.5 Pro research run
-> cited report
-> implementation handoff in Codex

Subscription / Billing Concern

If a user already pays for a ChatGPT plan that includes Deep Research, Codex should ideally be able to use those subscription Deep Research entitlements for this native research workflow.

Requiring separate API credits for the same Deep Research capability creates unnecessary friction, especially for users already paying for high-tier ChatGPT/Codex access.

Why This Matters

Before implementing non-trivial product, architecture, or research-heavy work, I want Codex to do exhaustive research from the current repo state. ChatGPT Deep Research is useful, but it does not naturally know the latest local workspace state. Codex does.

Native Deep Research in the Codex Mac app would make pre-implementation research current, auditable, and directly actionable from the same place where implementation will happen.

Related But Not Duplicates

• #2153 is mainly about moving or bridging ChatGPT and Codex sessions. This request is narrower: trigger a dedicated Deep Research task from Codex using live workspace context, especially in the Codex Mac app.
• #1469 was about supporting o3-deep-research as a model in the CLI/model path. This request is not to use Deep Research as the normal development model; it is to add a separate research-task workflow in Codex, with the Mac app as a primary target surface.