Group-scoped rules and drift detection

Status: Delivered
CAS: CAS-515
Delivered: 2026-04-25
PRs: #172, #173, #174, #175, #176, #183

What’s new

Casaconomy’s automatic categorisation rules can now be scoped to a specific Group. When you create or edit a trip-style Group with start and end dates, the app automatically generates a date-window rule that routes matching transactions into that Group without any manual setup. If you later edit the trip dates, a drift-detection system notices the mismatch and surfaces a prompt to accept or discard the updated rule — so your rules stay aligned with your groups without ongoing maintenance.

How to use it

Group-scoped rule browser:

Open a Group’s detail view and navigate to the Rules tab to see rules scoped to that group.
Group-scoped rules only match transactions when the active group context matches; generic rules continue to apply everywhere.

Auto-generated rules on Group create/edit:

When you create or edit a Group and set event dates (start/end), Casaconomy automatically generates a date-window rule for that group.
No visit to the Rules page is required; the rule appears there for reference.
If you edit the rule manually, the system marks it user_edited and stops auto-updating it.

Drift detection:

When a Group’s dates change and an auto-generated rule no longer matches them, a drift notification appears in two places:
- A strip on the main Dashboard
- A banner inside the Group detail view
Click Update rule to accept the new dates, or Keep current to lock your manual override and suppress further drift warnings for this rule.

What changed under the hood

Schema migration adds group_id, is_auto_generated, and user_edited columns to the rules table; rules without a group scope are unaffected.
New AssignToGroup rule action and evaluator route matching transactions into a specified group at categorisation time.
Auto-rule generation runs on create_group and edit_group: when event dates are present, a date-window rule is created or updated automatically (skipped if the rule has been user-edited).
Drift detection: new scan_rule_drift and resolve_rule_drift Tauri commands check for mismatches between a group’s dates and its auto-rules, returning structured RuleDrift payloads consumed by the notification UI.
New get_rules_by_group Tauri command allows the group rule browser to display only the rules belonging to a given group.
New frontend surfaces: group-scoped rule list inside the Group detail view, and drift notification strip on the dashboard and group detail banner with one-click resolution.

Why we built it

Manual categorisation rules are powerful but fragile — the moment a trip changes dates, all the date filters become wrong and transactions start missing their group. Auto- generating rules from group metadata removes the setup busywork, and drift detection closes the loop: rather than silently mis-categorising, the app tells the user something is out of sync and offers a one-click fix. Together these features make Groups genuinely low-maintenance for recurring use cases — annual trips, household budget periods, shared events.

Known limitations / follow-on work

Auto-rule generation only triggers for groups with explicit event dates; open-ended groups (e.g., a permanent household group) do not get auto-rules.
Drift detection currently covers date-window mismatches only; rule conditions beyond date ranges are not yet checked.
The group-scoped rule list does not support inline editing — rules must be edited via the main Rules page.
Multi-device rule sync is deferred to a later sync phase.