> ## Documentation Index > Fetch the complete documentation index at: https://anki.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Hooks Reference > A generated reference of all hooks and filters available in Anki for add-on development. This page lists all available hooks in Anki. It is generated from [`pylib/tools/genhooks.py`](https://github.com/ankitects/anki/blob/main/pylib/tools/genhooks.py) and [`qt/tools/genhooks_gui.py`](https://github.com/ankitects/anki/blob/main/qt/tools/genhooks_gui.py). See [Hooks & Filters](/addons/hooks-and-filters) for usage instructions. ## Backend Hooks (`anki.hooks`) ### `card_odue_was_invalid` No arguments. No docstring. *** ### `schema_will_change` **Args:** proceed: bool\ **Returns:** bool No docstring. *** ### `notes_will_be_deleted` **Args:** col: anki.collection.Collection, ids: Sequence\[anki.notes.NoteId] No docstring. *** ### `note_will_be_added` **Args:** col: anki.collection.Collection, note: anki.notes.Note, deck\_id: anki.decks.DeckId Allows modifying a note before it's added to the collection. This hook may be called both when users use the Add screen, and when add-ons like AnkiConnect add notes. It is not called when importing. If you wish to alter the Add screen, use gui\_hooks.add\_cards\_will\_add\_note instead. *** ### `media_files_did_export` **Args:** count: int Only used by legacy .apkg exporter. Will be deprecated in the future. *** ### `legacy_export_progress` **Args:** progress: str Temporary hook used in transition to new import/export code. *** ### `exporters_list_created` **Args:** exporters: list\[tuple\[str, Any]] No docstring. *** ### `media_file_filter` **Args:** txt: str\ **Returns:** str Allows manipulating the file path that media will be read from *** ### `field_filter` **Args:** field\_text: str, field\_name: str, filter\_name: str, ctx: anki.template.TemplateRenderContext\ **Returns:** str Allows you to define custom `{{filters:..}}` Your add-on can check filter\_name to decide whether it should modify field\_text or not before returning it. *** ### `note_will_flush` **Args:** note: Note Allow to change a note before it is added/updated in the database. *** ### `card_will_flush` **Args:** card: Card Allow to change a card before it is added/updated in the database. *** ### `card_did_render` **Args:** output: anki.template.TemplateRenderOutput, ctx: anki.template.TemplateRenderContext Can modify the resulting text after rendering completes. *** ### `importing_importers` **Args:** importers: list\[tuple\[str, Any]] Allows updating the list of importers. The resulting list is not saved and should be changed each time the filter is called. NOTE: Updates to the import/export code are expected in the coming months, and this hook may be replaced with another solution at that time. Tracked on [https://github.com/ankitects/anki/issues/1018](https://github.com/ankitects/anki/issues/1018) *** ### `deck_added` *(Obsolete)* **Args:** deck: anki.decks.DeckDict Obsolete, do not use. *** ### `note_type_added` *(Obsolete)* **Args:** notetype: anki.models.NotetypeDict Obsolete, do not use. *** ### `sync_stage_did_change` *(Obsolete)* **Args:** stage: str Obsolete, do not use. *** ### `sync_progress_did_change` *(Obsolete)* **Args:** msg: str Obsolete, do not use.