Add file content inclusion markers (different but similar to the current @filename) for full file content referencing in CLI

What feature would you like to see?

In Codex CLI, the user can direct mention the entire file content by markers similar to @ instead of letting the agent to read the files by chunks.

Problem Statement

Currently, when working with files in Codex CLI, the agent reads files in chunks which can be inefficient when the user wants to reference specific files in their entirety.

This can lead to:

• Incomplete context when discussing file contents
• Multiple round trips to read entire files
• Less precise control over what file content is included in the conversation

Proposed Solution

Implement a file inclusion syntax using markers (e.g., @@filename.ext) that would allow users to directly include entire file contents in their prompts.

Are you interested in implementing this feature?

_No response_

Additional information

_No response_