Fractional New-Card Scheduler

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Fractional New-Card Scheduler is an Anki add-on for decks that should introduce new cards more slowly than Anki's normal whole-number daily limits allow.

Instead of choosing between 0/day and 1/day, you can schedule patterns such as 1 every 3 days, set different limits by weekday, and spread related decks across a steady rotation. The add-on applies those plans through Anki's Today-only new-card limits, so changes are temporary and reset with Anki's next day.

It also includes deck health badges for decks that are blocked by 0/day limits or have no unsuspended new cards available.

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Install

Requires Anki 2.1.55 or newer.

From AnkiWeb

1. In Anki, open Tools -> Add-ons -> Get Add-ons....
2. Enter add-on code 304166926.
3. Restart Anki.
4. Use Tools -> Fractional Scheduler: Open Config to edit config.

AnkiWeb page: https://ankiweb.net/shared/info/304166926

From a GitHub release

Download the .ankiaddon from the latest tagged release, then use Tools → Add-ons → Install from file…. File installs do not receive AnkiWeb automatic updates.

From Source

1. Copy the addon folder into your Anki add-ons directory as its own folder, such as FractionalScheduler.
2. Restart Anki.
3. Use Tools -> Fractional Scheduler: Open Config to edit config.
4. Configure both scheduling and deck health badges from that dialog.

Features

• Each schedule can enable fractional limits, notify badges, both, or neither.
• Every-N-days schedules such as 1 card every 3 days.
• Three fractional strategies: balance_first, fraction_first, and hash.
• Day-of-week schedules with separate values for Mon-Sun.
• Ordered deck rules per schedule using exact names or shell-style wildcards. Prefix a rule with ! to exclude matching decks; a later matching rule includes them again.
• The picker supports selecting several decks at once. Pick deck... adds exact rules, while Add wildcard... and Exclude wildcard... add include/exclude subtree rules for every selected deck.
• Exact rules and simple subtree rules such as Deck::* or !Deck::* follow their root deck when it is renamed, including parent-deck renames. General patterns such as *Chemistry* retain their text pattern.
• Optional stable staggering for fraction_first and day-of-week schedules.
• Leaf-only matching so container decks do not receive fractional limits.
• Per-schedule notify descendant modes: direct only, any blocked descendant, all blocked descendants, or hide container badges.
• Filtered decks are skipped.
• Automatic apply on profile open, collection open, and optionally just before sync, with an at-most-once-per-day guard.
• Preview table for the next 14 days, including daily totals, persistent column widths, and grouping by identical schedules.
• Rebalance Offsets recomputes stable stagger assignments for the currently matched decks in a schedule.
• Read-only API for other add-ons via mw.fractional_scheduler_api.

See Scheduling Strategies for the tradeoffs between the fractional strategies.

Usage Notes

• The config dialog autosaves; there is no separate Save button.
• Deck rules run from top to bottom, and the last matching rule wins. For example, use Geography*, !GeoTrainer*, GeoTrainer::A*, and GeoTrainer::B::C to include Geography, exclude GeoTrainer, then add those two GeoTrainer branches back.
• Apply Now writes Today-only limits immediately for the matched decks.
• Before sync applies limits before collection sync when the installed Anki version exposes the pre-sync hook.
• Rebalance Offsets updates stored stagger assignments and preview data; deck limits change on the next apply.
• If you use a non-midnight Anki day rollover, the epoch calculation respects the rollover hour.
• addon/meta.json is local Anki state and is intentionally not tracked in git.

Public API

The add-on registers a read-only service on mw:

snapshot = mw.fractional_scheduler_api.get_schedule_health_snapshot(col)

It returns a dictionary keyed by deck id. Each value reports:

• deck_id
• deck_name
• schedule_id
• cycle_length_days
• has_future_positive_limit
• next_positive_day_offset

The service only includes matched, non-dynamic decks that survive leaf_only filtering. A deck is considered to have a future positive limit if, within one full schedule cycle, at least one day yields > 0 new cards.

Config Example

{
  "epoch": "2026-01-01",
  "schedules": [
    {
      "id": "bio-slow",
      "type": "every_n_days",
      "m": 1,
      "n": 3,
      "fractional_strategy": "balance_first",
      "targets": ["Biology::*"],
      "fractional_enabled": true,
      "notify_enabled": true,
      "notify_descendant_mode": "direct_only",
      "leaf_only": true,
      "stagger": {"mode": "stable"}
    },
    {
      "id": "chemistry-notify",
      "type": "every_n_days",
      "m": 1,
      "n": 1,
      "targets": ["*Chemistry*"],
      "fractional_enabled": false,
      "notify_enabled": true,
      "notify_descendant_mode": "all_included_descendants_blocked",
      "leaf_only": true
    }
  ],
  "defaults": {
    "apply_on_profile_open": true,
    "apply_on_collection_open": true,
    "apply_on_sync": false,
    "apply_once_per_day": true,
    "dry_run": false,
    "log_level": "info"
  }
}

Debug Logging

• Debug logging is off by default and no queue/history diagnostics are shown in the UI.
• To enable temporary scheduler diagnostics before Anki loads the add-on, start Anki with the environment variable FRACTIONAL_SCHEDULER_DEBUG=1.
• When enabled, the add-on appends JSON lines to fractional-scheduler-debug.log in the platform temporary directory.
• The log may include deck names, schedule ids, queue order, and introduction-history details, so treat it as potentially sensitive and delete it when you are done.
• When debug logging is not enabled, the add-on removes any old temporary debug log on profile/collection open.

GUI Smoke Test

The repository has an anki-addon-workbench config and probe add-on for a disposable Anki GUI smoke test. With anki-workbench installed, run:

anki-workbench smoke --xvfb

The probe verifies that the add-on module loads and that Fractional Scheduler: Open Config appears in Anki's Tools menu.

Release

Release packaging uses the sibling anki-addon-release project.

make release

That target validates the manifest/listing metadata, builds dist/fractional-new-card-scheduler.ankiaddon, inspects the archive contents, and runs an AnkiWeb dry run. Use make release-handoff to write handoff files for a browser/manual upload, or make release-login and make release-publish when publishing through the release browser profile with credentials from a git-ignored .env file.

License

MIT. See LICENSE.

Support continued development: ritornello.dev/support.