kandev/docs/plans/managed-runtime-default-activation/task-01-reconcile-default-generations.md

id, title, status, wave, depends_on, plan, requirements, acceptance_criteria, system_design

id	title	status	wave	depends_on	plan	requirements	acceptance_criteria	system_design
01-reconcile-default-generations	Reconcile managed runtime generations	done	1		plan.md	REQ-AGENTS-RUNTIME-UPDATES-001 REQ-AGENTS-RUNTIME-UPDATES-002	AC-AGENTS-RUNTIME-UPDATES-001.5 AC-AGENTS-RUNTIME-UPDATES-001.6 AC-AGENTS-RUNTIME-UPDATES-002.1 AC-AGENTS-RUNTIME-UPDATES-002.2 AC-AGENTS-RUNTIME-UPDATES-002.4 AC-AGENTS-RUNTIME-UPDATES-002.7	../../specs/agents/system-design/runtime-default-activation.md

Task 01: Reconcile Managed Runtime Generations

Summary

Add the default-generation model and the idempotent store operation. The operation removes an older selection before it records the current generation.

In scope

• Add trusted package and default-version generation records.
• Reconcile missing, matching, and changed markers.
• Treat legacy unmarked selections as stale.
• Keep the current active-selection key and JSON shape.
• Return all storage errors.

Out of scope

• Backend startup wiring.
• Runtime command construction.
• User-interface or API changes.

Acceptance

• A matching generation preserves the active selection without a write.
• A missing or changed generation deletes the selection before marker storage.
• A failed operation returns an error and remains safe to retry.

Verification

go test ./internal/agent/managedruntime -count=1

Run the command from apps/backend.

Files likely touched

• apps/backend/internal/agent/managedruntime/selection.go
• apps/backend/internal/agent/managedruntime/selection_test.go

Dependencies

None.

Risks

• The delete and marker write are separate operations. The order must keep retries safe after interruption.
• A malformed marker must not preserve an old selection.

Parallelism

sequential

Inputs

• REQ-AGENTS-RUNTIME-UPDATES-001
• REQ-AGENTS-RUNTIME-UPDATES-002
• docs/specs/agents/system-design/runtime-default-activation.md
• Existing managedruntime.Store tests and system/settings.Store behavior.

Results

Implemented DefaultGeneration and idempotent Store.ReconcileDefaults. Matching markers preserve selections; missing, changed, or malformed markers clear the selection before saving the current marker. Storage errors stop reconciliation and leave it safe to retry.

Verification: go test ./internal/agent/managedruntime -count=1 passed.