Summary
Add an Engine-level mechanism for restricting which policy operands are admissible.
The restriction should be authoritative in core, not merely an acquisition hint for Directive Drafter or an integration-specific validator.
Motivation
Some enforcement points need a finite policy vocabulary. For example, an agent/runtime integration may want to permit only a bounded set of policy operands that the host can actually enforce.
If only Directive Drafter is constrained, the restriction is advisory: another caller could still submit a canonical directive using an arbitrary operand and Engine would accept it. Engine therefore needs to enforce the operand domain itself.
Architectural direction
- Attach/configure the allowed policy operand domain on an
Engine.
- Treat the restriction as Engine configuration rather than ordinary mutable authoritative state.
- Enforce the restriction on every directive application path.
- Keep premise handling out of scope; this is specifically about policy operands.
- Directive Drafter may later consume the same configured operand set for constrained drafting, but Engine remains authoritative.
- Integrations choose the operand domain appropriate to their enforcement point.
Deferred design questions
Do not resolve these as part of the initial architectural decision unless needed:
- exact public API shape;
- checkpoint/import compatibility semantics;
- compound policy expressions such as
and / or;
- interaction with proposed partial-match behavior;
- quoting/escaping for operand text that may overlap grammar operators.
Summary
Add an Engine-level mechanism for restricting which policy operands are admissible.
The restriction should be authoritative in core, not merely an acquisition hint for Directive Drafter or an integration-specific validator.
Motivation
Some enforcement points need a finite policy vocabulary. For example, an agent/runtime integration may want to permit only a bounded set of policy operands that the host can actually enforce.
If only Directive Drafter is constrained, the restriction is advisory: another caller could still submit a canonical directive using an arbitrary operand and Engine would accept it. Engine therefore needs to enforce the operand domain itself.
Architectural direction
Engine.Deferred design questions
Do not resolve these as part of the initial architectural decision unless needed:
and/or;