# Internal (unstable)

> Internal switches with no stability promise: listed here for support engineers, never built on. May change or disappear in any release.

| Hook | Kind | Tier | Since | Summary |
| --- | --- | --- | --- | --- |
| [`boolean_smtp_api_debug`](/hooks/boolean_smtp_api_debug/) (internal) | action | C | 1.0.0 | Fires with diagnostic details after an API-mode send attempt, whatever its outcome. |
| [`boolean_smtp_api_debug_response_enabled`](/hooks/boolean_smtp_api_debug_response_enabled/) (internal) | filter | C | 1.0.0 | Filters whether raw debug data may be attached to an admin REST response. |
| [`boolean_smtp_debug_attach_api_debug`](/hooks/boolean_smtp_debug_attach_api_debug/) (internal) | filter | C | 1.0.0 | Filters the legacy API debug response toggle. |
| [`boolean_smtp_debug_http_enabled`](/hooks/boolean_smtp_debug_http_enabled/) (internal) | filter | C | 1.0.0 | Filters whether the outgoing-HTTP debug channel is enabled. |
| [`boolean_smtp_debug_http_log_style`](/hooks/boolean_smtp_debug_http_log_style/) (internal) | filter | C | 1.0.0 | Filters how outgoing HTTP exchanges are formatted in the `requests` log channel. |
| [`boolean_smtp_debug_http_mailer_only`](/hooks/boolean_smtp_debug_http_mailer_only/) (internal) | filter | C | 1.0.0 | Filters whether the outgoing-HTTP debug channel is restricted to mail-provider URLs. |
| [`boolean_smtp_debug_http_mailer_url_match`](/hooks/boolean_smtp_debug_http_mailer_url_match/) (internal) | filter | C | 1.0.0 | Filters whether a URL not matched by the built-in provider list counts as mail-related. |
| [`boolean_smtp_debug_log_error`](/hooks/boolean_smtp_debug_log_error/) (internal) | action | C | 1.0.0 | Fires when a debug session could not be stored. |
| [`boolean_smtp_debug_mailer_action_enabled`](/hooks/boolean_smtp_debug_mailer_action_enabled/) (internal) | filter | C | 1.0.0 | Filters whether the mailer-diagnostics debug channel is enabled. |
| [`boolean_smtp_debug_mask_visible_suffix_length`](/hooks/boolean_smtp_debug_mask_visible_suffix_length/) (internal) | filter | C | 1.0.0 | Filters the number of trailing characters left visible when a value is masked. |
| [`boolean_smtp_debug_output_xhr`](/hooks/boolean_smtp_debug_output_xhr/) (internal) | filter | C | 1.0.0 | Filters the legacy API debug response toggle (alias of `boolean_smtp_debug_attach_api_debug`). |
| [`boolean_smtp_debug_queries_enabled`](/hooks/boolean_smtp_debug_queries_enabled/) (internal) | filter | C | 1.0.0 | Filters whether the database-query debug channel is enabled. |
| [`boolean_smtp_debug_query_call_site_include_frame`](/hooks/boolean_smtp_debug_query_call_site_include_frame/) (internal) | filter | C | 1.0.0 | Filters whether a backtrace frame may be used as a query's recorded call site. |
| [`boolean_smtp_debug_request_enabled`](/hooks/boolean_smtp_debug_request_enabled/) (internal) | filter | C | 1.0.0 | Filters whether the incoming-request/REST debug channel is enabled. |
| [`boolean_smtp_debug_request_secret_visibility`](/hooks/boolean_smtp_debug_request_secret_visibility/) (internal) | filter | C | 1.0.0 | Filters the secret visibility used for REST/POST request payload blocks in the `requests` log channel. |
| [`boolean_smtp_debug_scope`](/hooks/boolean_smtp_debug_scope/) (internal) | filter | C | 1.0.0 | Filters the debug logging scope. |
| [`boolean_smtp_debug_secret_visibility`](/hooks/boolean_smtp_debug_secret_visibility/) (internal) | filter | C | 1.0.0 | Filters how sensitive values appear in debug logs and API debug responses. |
| [`boolean_smtp_debug_sensitive_key`](/hooks/boolean_smtp_debug_sensitive_key/) (internal) | filter | C | 1.0.0 | Filters whether a data key is treated as sensitive for debug-log redaction. |
| [`boolean_smtp_debug_should_log_http`](/hooks/boolean_smtp_debug_should_log_http/) (internal) | filter | C | 1.0.0 | Filters whether an outgoing HTTP request/response is recorded to the debug log. |
| [`boolean_smtp_log_mailer_resolved_to_error_log`](/hooks/boolean_smtp_log_mailer_resolved_to_error_log/) (internal) | filter | C | 1.0.0 | Filters whether the resolved mailer diagnostics are written to the plugin log. |
| [`boolean_smtp_oauth_debug_ui`](/hooks/boolean_smtp_oauth_debug_ui/) (internal) | filter | C | 1.0.0 | Filters whether the admin UI shows raw OAuth provider diagnostics. |
| [`boolean_smtp_vite_dev_server_url`](/hooks/boolean_smtp_vite_dev_server_url/) (internal) | filter | C | 1.0.0 | Filters the resolved Vite dev-server URL. |