AbstractAbstract ReadonlyKeyStable identifier for this provider (e.g. 'agent-mentions'). Used as the
ClassFactory registration key and by ExcludedTriggerKeys filtering.
ReadonlyPriorityOrdering weight — higher runs first. When multiple providers share a TriggerChar, results are concatenated in priority order (then Key order).
Abstract ReadonlyTriggerThe single character that opens this provider's autocomplete (e.g. '@').
Returns the suggestions for the current query. Called on every keystroke after an active trigger; implementations should be fast (serve from warm caches) and must never throw — return [] on failure.
Warm the shared suggestion engine so the first keystroke after a trigger is fast. Safe to call repeatedly/concurrently — the engine has a promise-locked initialize.
Shared base for the conversations composer plugins (agent-mentions / record-mentions / skill-commands). Each concrete provider owns one trigger char; all of them delegate to the shared MentionAutocompleteService engine, which loads its permission-filtered caches once per session and ranks suggestions per trigger.
Fail-closed: with no context user the AI-backed suggestion sets can't be permission filtered, so the providers return [] rather than leaking anything.