Core files

Use this page when deciding where a change belongs.

File or directory	Edit when
`run_agent.py`	You need to change the agent loop, budgets, callbacks, or agent-level tools.
`model_tools.py`	You need to change tool discovery or function-call dispatch.
`toolsets.py`	You need to expose a built-in tool through a toolset.
`cli.py`	You need to change interactive CLI behavior.
`arcen_cli/commands.py`	You need to add or edit slash command definitions.
`gateway/run.py`	You need gateway runtime behavior or command dispatch.
`gateway/platforms`	You need a messaging platform adapter.
`plugins`	You need extension behavior without core edits.
`ui-tui`	You need the Ink terminal UI.
`tui_gateway`	You need TUI backend methods or events.

Tool dependency chain

tools/registry.py
  -> tools/*.py
  -> model_tools.py
  -> run_agent.py, cli.py, batch_runner.py, environments

Loader	Used by
`load_cli_config()` in `cli.py`	Interactive CLI.
`load_config()` in `arcen_cli/config.py`	Setup, tools, and most subcommands.
Direct YAML loading in `gateway/run.py`	Gateway runtime.