Reference: `runtimes/*.yaml`

Each YAML file under runtimes/ defines one runtime adapter. File stem = runtime id used in agent runtime: fields.

Fields

Field	Type	Required	Notes
binary	string	yes	CLI binary name (resolved on $PATH) or absolute path.
supports_mcp	bool	no, default false	Must be true for participation in the mailbox. All shipped runtimes set this.
session_resume	string	no	How sessions resume across restarts: --continue, profile, none, or a runtime-specific flag.
default_model	string	no	Used when an agent doesn’t set its own model:.
env	map<string,string>	no	Merged into the agent’s environment on launch.

Shipped adapters

• claude-code.yaml — Anthropic’s Claude Code CLI.
• codex.yaml — OpenAI’s Codex CLI.
• gemini.yaml — Google’s Gemini CLI.

Example

# runtimes/aider.yaml — hypothetical adapter for aider
binary: aider
supports_mcp: true
session_resume: "none"
default_model: sonnet
env:
  AIDER_CHAT_HISTORY_FILE: ""

You’d also need a run_aider branch in bin/agent-wrapper.sh that knows how to pass --mcp-config and --system-instruction to aider.