ADR 0097: Place global defaults under the AI settings destination

• Status: Accepted
• Date: 2026-08-18
• Deciders: PI-Desktop core
• Related: D166, D238, D239, ADR 0096

Context

The flat Settings directory removed redundant navigation levels, but the Basics page still owned a Defaults card containing the default operating mode, command shell, and Enter-to-send preference. These controls change agent behavior rather than application appearance, so their location made the Basics page mix visual preferences with global AI behavior.

Decision

Keep the eight-destination Settings directory unchanged. Basics owns the Appearance card and platform-supported close behavior. The 全局 AI / AI destination owns the Permissions card and the Defaults card, whose rows are:

• default operating mode (Agent / Plan / Goal)
• command shell selection and its host-backed fallback status
• Enter-to-send

The Model configuration destination continues to own the default provider/model selector because it is coupled to provider readiness and model identity. This change only moves renderer content and Settings search ownership; persisted settings, host APIs, runtime semantics, and deep-link contracts do not change.

Consequences

• Basics has a focused visual and application-preference scope.
• Global AI presents the behavior controls users expect to affect agent turns.
• Settings search routes mode, command shell, and Enter-to-send queries to AI.
• Existing persisted settings and runtime behavior remain unchanged.

Alternatives

Keep Defaults in Basics

Rejected because the card mixes appearance with agent execution behavior.

Add a separate Behavior destination

Rejected because it would expand the flat directory for three closely related controls that already have a clear owner in AI.

Move the controls to Model configuration

Rejected because operating mode, command shell, and Enter-to-send are global interaction behavior and do not depend on provider/model readiness.

References

• docs/spec/04-ux/06-settings-ia.md
• docs/spec/04-ux/08-component-spec.md
• docs/spec/06-delivery/04-e2e-test-plan.md