Feature Request: Support for a Project-Specific System Prompt File (e.g., COPILOT.md)

[AungMyoKyaw]

Describe the feature or problem you'd like to solve

This feature would function similarly to how Claude Code CLI utilizes a CLAUDE.md file.

Proposed solution

I propose adding support for a project-specific configuration file, such as COPILOT.md, to the GitHub Copilot CLI.

This feature would function similarly to how Claude Code CLI utilizes a CLAUDE.md file.

🚀 Motivation

The primary goal is to allow users to define a persistent, project-level system prompt that the Copilot CLI can read and include in its context for every command executed within that repository.

Currently, when using the Copilot CLI on a project, a lot of project-specific context (e.g., framework details, preferred libraries, coding style, architectural constraints, security policies) needs to be either implicitly inferred or manually provided with each prompt.

Example prompts or workflows

No response

Additional context

No response

[thawkins]

Why not just AGENTS.md

See https://AGENTS.md

[0xHarlan]

I think you can achieve that by using the instructions files in .github folder, see: docs.github.com. I tried it earlier and it seems to work, the agent pulls the instructions at the beginning of the session and then uses it. However, AGENTS.md is listed aswell in the Copilot CLI tab but doesn't seem to be pulled automatically.