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You can provide custom instructions to Symbiotic Code by creating an AGENTS.md file. This is similar to Cursor’s rules. It contains instructions that will be included in the LLM’s context to customize its behavior for your specific project.

Initialize

To create a new AGENTS.md file, you can run the /init command in Symbiotic Code.
You should commit your project’s AGENTS.md file to Git.
/init scans the important files in your repo, may ask a couple of targeted questions when the codebase cannot answer them, and then creates or updates AGENTS.md with concise project-specific guidance. It focuses on the things future agent sessions are most likely to need:
  • build, lint, and test commands
  • command order and focused verification steps when they matter
  • architecture and repo structure that are not obvious from filenames alone
  • project-specific conventions, setup quirks, and operational gotchas
  • references to existing instruction sources like Cursor or Copilot rules
If you already have an AGENTS.md file, /init will improve it in place instead of blindly replacing it.

Types

Symbiotic Code also supports reading the AGENTS.md file from multiple locations. And this serves different purposes.

Project

Place an AGENTS.md in your project root for project-specific rules. These only apply when you are working in this directory or its sub-directories.

Global

You can also have global rules in a ~/.config/symbiotic/AGENTS.md file. This gets applied across all Symbiotic Code sessions. Since this isn’t committed to Git or shared with your team, we recommend using this to specify any personal rules that the LLM should follow.

Claude Code Compatibility

For users migrating from Claude Code, Symbiotic Code supports Claude Code’s file conventions as fallbacks:
  • Project rules: CLAUDE.md in your project directory (used if no AGENTS.md exists)
  • Global rules: ~/.claude/CLAUDE.md (used if no ~/.config/symbiotic/AGENTS.md exists)
  • Skills: ~/.claude/skills/ — see Agent Skills for details
To disable Claude Code compatibility, set one of these environment variables:

Precedence

When Symbiotic Code starts, it looks for rule files in this order:
  • Local files by traversing up from the current directory (AGENTS.md, CLAUDE.md)
  • Global file at ~/.config/symbiotic/AGENTS.md
  • Claude Code file at ~/.claude/CLAUDE.md (unless disabled)
The first matching file wins in each category. For example, if you have both AGENTS.md and CLAUDE.md, only AGENTS.md is used. Similarly, ~/.config/symbiotic/AGENTS.md takes precedence over ~/.claude/CLAUDE.md.

Custom Instructions

You can specify custom instruction files in your symbiotic.json or the global ~/.config/symbioticsymbiotic.json. This allows you and your team to reuse existing rules rather than having to duplicate them to AGENTS.md. Example:
symbiotic.json
You can also use remote URLs to load instructions from the web.
symbiotic.json
Remote instructions are fetched with a 5 second timeout. All instruction files are combined with your AGENTS.md files.

Referencing External Files

While Symbiotic Code doesn’t automatically parse file references in AGENTS.md, you can achieve similar functionality in two ways:

Using symbiotic.json

The recommended approach is to use the instructions field in symbiotic.json:
symbiotic.json

Manual Instructions in AGENTS.md

You can teach Symbiotic Code to read external files by providing explicit instructions in your AGENTS.md. Here’s a practical example:
AGENTS.md
This approach allows you to:
  • Create modular, reusable rule files
  • Share rules across projects via symlinks or git submodules
  • Keep AGENTS.md concise while referencing detailed guidelines
  • Ensure Symbiotic Code loads files only when needed for the specific task
For monorepos or projects with shared standards, using symbiotic.json with glob patterns (like packages/*/AGENTS.md) is more maintainable than manual instructions.