@callback accounts() :: [{uuid :: String.t(), name :: String.t(), polled? :: boolean()}]

Per-integration opt-out list for the admin panel's Accounts column: {uuid, name, polled?} for every currently-active account. Optional — only define this if the provider has a genuine multi-account opt-out concept (Brevo does; SES doesn't). A tracker that skips it gets nil (see accounts/1), which the panel reads as "not applicable" and renders as a plain placeholder in the Accounts cell rather than a checkbox list.

@callback eligible?() :: boolean()

Is there a working event source this tracker can poll right now? Folds every feature/source gate (integration presence, feature flags) — everything EXCEPT the operator's polling on/off switch.

@callback enabled?() :: boolean()

The operator's polling master toggle only (not eligibility).

@callback integration_count() :: non_neg_integer()

Admin panel's Integration-column count ("2 active integrations"). Optional — trackers without a working default (there isn't one: every tracker has some meaningful count) may still skip it; a tracker that doesn't define this gets 1/0 from eligible?/0 instead (see integration_count/1). Defining it explicitly is strongly recommended whenever "how many" means something more precise than a bare yes/no (Brevo's multi-account case).

@callback interval_ms() :: pos_integer()

Cadence (ms) the next self-schedule should use — the tracker's own configured interval.

@callback label() :: String.t()

Human-readable name for the admin panel ("Amazon SES", "Brevo").

@callback last_polled_at() :: DateTime.t() | nil

This tracker's own durable "last completed cycle" timestamp, when it keeps one. Optional — a tracker that skips it falls back to the generic Oban-history derivation (see last_polled_at/1), which is correct but only as long as the completed job still exists. Define this whenever the tracker's polling interval can outlive Oban.Plugins.Pruner's max_age (Brevo's floor alone is 30s against a 60s default), or the panel's Last-poll column reads "Never polled yet" for a perfectly healthy chain.

@callback min_interval_ms() :: pos_integer()

The floor set_polling_interval/1 (the informal Manager API — see EventTrackerRegistry) enforces for this tracker, e.g. SES's 1_000 vs Brevo's 30_000 (a lower bound driven by the provider's own API, not a policy choice this behaviour makes). Not optional — every tracker's interval editor needs some real floor to show as the input's client-side min; a wrong/missing one either lets an operator type a value the server will reject anyway, or falsely floors a provider that could safely poll faster (dual-review P2 fix 2/5).

@callback poll_cycle(context :: map()) :: :ok | {:error, term()}

Run one poll cycle synchronously, outside of Oban's own scheduling — for callers that want an immediate, in-process cycle (e.g. a future admin panel "Poll now" action) rather than queueing a job. Delegates to the existing *PollingJob.perform/1 logic; the self-scheduling job/ worker itself is unchanged by this behaviour.

@callback provider_kind() :: String.t()

The discriminator — matches SendProfile.provider_kind ("aws_ses", "brevo_api", …).

@callback settings_component() :: module() | nil

The Phoenix.LiveComponent rendering this tracker's own provider-specific settings, shown inside its expanded row in the "Delivery event tracking" panel. Optional — a tracker that skips it (or returns nil) gets a plain "no separate settings" note instead (see settings_component/1).

Only the module is returned, never {module, assigns}: the panel has no provider-specific data to hand down, and the component is required to load its own state in update/2 — a caller-supplied assigns map would be a second source of truth for the same settings, and the panel would have to know what every provider needs in order to build it.

@callback toggle_account_polling(uuid :: String.t()) :: {:ok, term()} | {:error, term()}

Flips one integration's polling opt-out (see accounts/0). Optional — a tracker that skips it (because it skipped accounts/0 too) gets a safe no-op (see toggle_account_polling/2) instead of an UndefinedFunctionError from a stale/forged panel action.

@callback worker() :: module()

The Oban worker module backing this tracker's self-scheduling chain.