Add @file command support for non-interactive cli input

[zfflxx]

What would you like to be added?

Extend the existing @file command functionality to work in non-interactive (piped) mode. Currently, when users input @filename in interactive UI, the file content is automatically read and added to the chat context. This same logic should be implemented for non-interactive mode.

Why is this needed?

In non-interactive cli mode, without direct file reading, Gemini cli needs to first create a tool call request and then read the file, requiring multiple API calls and taking longer to complete.

For example, Claude Code supports: claude -p "explain this code to me @test.js" - completing the task in a single interaction without additional ReadFile tool calls. Gemini CLI should provide the same efficient workflow.

Benefits:

• Performance: Eliminates extra API calls and reduces response time
• Consistency: Unified @file behavior across interactive and non-interactive modes
• Efficiency: Enables single-command workflows for file-based queries

Additional context

No response

[allenhutchison]

Non interative mode is supposed to be more like a traditional command line interface where you would pipe the contents of your file into the command. To achieve this you would do the following:

cat test.js | gemini --prompt "Explain this code to me.

This keeps our TUI code focused on the TUI and maintains the separation of concerns between the two. If you want to pipe whole directories to your CLI invocation I would recommend https://github.com/simonw/files-to-prompt in that case you would run something like:

files-to-prompt src/gemini-cli/packages/core | gemini --prompt "Explain this code to me"