Summary

mam_get_phone_data_before_send has ~70 subscribers across the MAM Suite. Their relative ordering matters — some sections depend on others having already injected. The convention below has been observed by every existing subscriber for years; new code should follow it.

The priority bands

Critical ordering contracts

home_cats runs at priority 1000

MAM_Main_Manager::manage_phone_data builds the home-screen category structure. Every subscriber that contributes to home_cats must run before priority 1000 — otherwise its category won’t be picked up.

If you need to influence the home-screen home_cats, register at priority < 1000 (10 is fine).

Use-case overrides run at 9999

Use-case plugins like mam-meal-genie and mam-medicoach need to fully replace sections of the response. They register at priority 9999 to run last. If your sibling plugin needs to read final values, register at 9999+.

GeoDirectory before GeoFilters

Both register at priority 10 (default), but mam-geofilters expects mam-geodirectory‘s listings to already be present. The implicit ordering depends on registration order — if you change registration order in register_*() methods, you can break GeoFilters silently.

Chat before notifications-manager

Similar: mam_chat_manager injects thread counts; mam_notification_manager reads them to compute notification badges. Both at priority 10 — registration order matters.

Choosing a priority for new code

When in doubt: priority 10. It’s where 80% of subscribers live and ordering surprises are unlikely.

Anti-patterns

• Don’t register at priority 1000 unless you’re injecting something that depends on every other subscriber’s data. That slot is home_cats.
• Don’t register at priority -1 / 0 to run “first” — base settings owns priority 1; the convention starts there.
• Don’t depend on home_cats from priority 999. Run after 1000 (e.g., 1001) instead.
• Don’t try to invert ordering with remove_filter + add_filter — the registration order in mam-main’s bootstrap is intentional.

Diagnosis

apply_filters ordering is “lowest priority first.” To enumerate current subscribers in order:

global $wp_filter;
$cb = $wp_filter['mam_get_phone_data_before_send'] ?? null;
if ( $cb ) {
    foreach ( $cb->callbacks as $priority => $callbacks ) {
        echo "Priority $priority:n";
        foreach ( $callbacks as $cb_id => $cb_def ) {
            echo "  - $cb_idn";
        }
    }
}

Related articles

• Phone data pipeline overview
• Phone data pipeline phases
• Mobile JSON shape
• Hook: mam_get_phone_data_before_send
• Hook: mam_local_app_data

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