Engines & ports
Every Crew member is pluggable: the Yard depends on a port; a default engine ships; operators may swap engines that pass the same contract.
Why ports
| Benefit | Detail |
|---|---|
| Swap brains | Better model / specialist engine without rewriting dispatch |
| Testability | Fake engines in CI |
| Policy | Engine choice is still RBAC-scoped |
| Audit | Tool calls and outputs remain events regardless of engine |
Patterns
- Default built-in engine per operator
- Optional external engines (e.g. HolmesGPT-class for SRE)
- MCP tool surface stays stable — engines are implementation
- Never give an engine ambient admin outside its role
Related
Shared model · SRE · MCP