Here are the data structures with brief descriptions:

Cdual_poll_result_t	Result of one dual_channel_poll_link_once() attempt
Csapi_appmanager_checkpoint_config_t	Optional built-in checkpoint rendezvous configuration (ADR-019/ADR-034)
Csapi_appmanager_config_t	Application manager configuration
Csapi_appmanager_operations_t	Application lifecycle operations
Csapi_appmanager_state_t	Application manager runtime state
Csapi_buffer_t	Mutable, bounds-tracked view over caller-owned storage
Csapi_channel_config_t	Configuration for sapi_channel_init()
Csapi_channel_health_t	Health statistics for one vital channel
Csapi_channel_service_backend_t	Backend implementation for named channel operations
Csapi_channel_service_storage_t	Caller-owned storage for one named channel service instance
Csapi_channel_storage_t	Storage for one vital channel instance (opaque to caller)
Csapi_checkpoint_config_t	Checkpoint configuration
Csapi_checksum_manager_t
Csapi_checksum_result_t	Checksum result for validation
Csapi_checksum_stats_t	Checksum statistics for monitoring
Csapi_clocksync_backend_t	Backend vtable: an integrator's implementation of clock synchronization for a specific mechanism (PTP/GPS/NTP/custom). Any slot may be NULL if unsupported by the backend (-> SAPI_STATUS_NOT_SUPPORTED)
Csapi_const_buffer_t	Read-only view of a buffer's currently valid bytes. Grants no write access to the underlying storage
Csapi_cross_comparator_config_t	Configuration for sapi_cross_comparator_init()
Csapi_cross_comparator_storage_t	Storage for one cross-comparator instance (opaque to caller). No dynamic memory
Csapi_dual_ack_frame_t	SAPI_DUAL_FRAME_KIND_ACK payload
Csapi_dual_channel_config_t	Configuration for sapi_dual_channel_init()
Csapi_dual_channel_t	One sapi_dual_channel_t instance's state. Caller-owned storage; every field is private - reach it only through the functions below
Csapi_dual_frame_header_t	Common 4-byte header prefixing every Layer-2 frame; kept a fixed 4 bytes (not just 1) so the fields that follow in sapi_dual_ack_frame_t/sapi_dual_state_frame_t stay naturally aligned
Csapi_dual_heartbeat_frame_t	SAPI_DUAL_FRAME_KIND_HEARTBEAT payload - connection maintenance heartbeat
Csapi_dual_msgchannel_config_t	Configuration for sapi_dual_msgchannel_init()
Csapi_dual_msgchannel_t	One sapi_dual_msgchannel_t instance's state. Caller-owned storage (REQ-DUAL-MSGCHANNEL-001); opaque in practice, exposed here (not via SAFEAPI_DECLARE_STORAGE) only because its size is already small and fixed - callers must still treat every field as private and only reach it through the functions below
Csapi_dual_negotiator_config_t	Configuration for sapi_dual_negotiator_init()
Csapi_dual_negotiator_t	One sapi_dual_negotiator_t instance's state. Caller-owned storage; every field is private - reach it only through the functions below
Csapi_dual_state_frame_t	SAPI_DUAL_FRAME_KIND_STATE payload - sapi_dual_negotiator_t's own periodic beacon
Csapi_ipc_backend_t	Backend vtable: an integrator's implementation of the IPC service for a specific OS/RTOS (ADR-005). Any slot may be NULL if unsupported by the backend (-> SAPI_STATUS_NOT_SUPPORTED)
Csapi_ipc_config_t	Configuration for sapi_ipc_create()
Csapi_ipc_pubsub_subscriber_config_t	Configuration for a subscriber
Csapi_ipc_pubsub_topic_config_t	Configuration for a pub-sub topic
Csapi_ipc_rr_client_config_t	Configuration for request-reply client
Csapi_ipc_rr_request_t	Incoming request with context for sending reply
Csapi_ipc_rr_server_config_t	Configuration for request-reply server
Csapi_log_backend_t	Backend vtable: an integrator's implementation of the logging sink (ADR-005). Unlike every other OAL service, an unregistered backend is not an error here: sapi_log_write() with no backend registered silently does nothing, consistent with REQ-OAL-LOG-001 (logging must never affect caller control flow)
Csapi_log_fields_t	Bounded builder for sapi_log_write_event()'s extra_fields (or info) argument: accumulates space-separated key=value pairs, each typed at the call site, so a caller adding a couple of variable values does not hand-roll a sapi_string_concat()/sapi_string_append_u32() chain every time (MISRA C:2012 Rule 17.1 rules out a printf-style variadic here)
Csapi_log_level_name_t	One canonical level spelling <-> value pair for sapi_log_level_from_string()
Csapi_mem_pool_backend_t	Backend vtable: an integrator's implementation of the memory pool service (ADR-005). Any slot may be NULL if unsupported by the backend (-> SAPI_STATUS_NOT_SUPPORTED)
Csapi_mem_pool_config_t	Configuration for sapi_mem_pool_create()
Csapi_mutex_backend_t	Backend vtable: an integrator's implementation of the mutex service for a specific OS/RTOS/BSP target (ADR-033). Any slot may be NULL if that operation is unsupported by the backend, in which case the corresponding sapi_mutex_* call returns SAPI_STATUS_NOT_SUPPORTED
Csapi_netlink_backend_t	Backend vtable: an integrator's implementation of the network link service for a specific transport/target (ADR-005). Any slot may be NULL if unsupported by the backend (-> SAPI_STATUS_NOT_SUPPORTED)
Csapi_netlink_config_t	Configuration for sapi_netlink_open()
Csapi_nvm_backend_t	Backend vtable: an integrator's implementation of the NVM service for a specific storage medium (ADR-005). Any slot may be NULL if unsupported by the backend (-> SAPI_STATUS_NOT_SUPPORTED)
Csapi_nvm_config_t	Configuration for sapi_nvm_open()
Csapi_platform_backend_t	Backend vtable: an integrator's implementation of the real-time platform bring-up for a specific target (ADR-005)
Csapi_reboot_backend_t	Backend vtable: an integrator's implementation of the reboot mechanism for a specific target (ADR-005)
Csapi_safe_ptr_t	A bounds-checked, canary-protected wrapper around one raw memory region. Opaque to callers in spirit (every field is manipulated only through the functions below) but a plain struct, not a handle, so it can be embedded directly in a caller's own statically-allocated storage - no dynamic allocation, matching CLAUDE.md
Csapi_safechannel_config_t	Configuration for sapi_safechannel_open()
C[union].as
Csapi_safechannel_dual_config_t	Configuration specific to SAPI_SAFECHANNEL_TYPE_DUAL_REDUNDANT
Csapi_safechannel_endpoint_t	One remote endpoint to open internally - replaces a caller- supplied sapi_netlink_handle_t (ADR-022 section 2.2)
Csapi_safechannel_t	Caller-owned storage for one sapi_safechannel_t instance. Every field is private - reach it only through the functions below. No dynamic allocation (REQ-SAFECHANNEL-002): sized to hold up to SAPI_SAFECHANNEL_MAX_LINKS opened netlink links plus whichever of sapi_dual_channel_t/sapi_channel_t is in use
C[union].impl
C[struct].impl.vital
Csapi_safechannel_vital_config_t	Configuration specific to SAPI_SAFECHANNEL_TYPE_VITAL_VOTED
Csapi_string_t	Bounded string: buf.length is the string length, not counting a NUL
Csapi_task_backend_t	Backend vtable: an integrator's implementation of the task scheduling service for a specific OS/RTOS (ADR-005). Any slot may be NULL if unsupported by the backend (-> SAPI_STATUS_NOT_SUPPORTED)
Csapi_task_config_t	Configuration for sapi_task_create()
Csapi_timer_backend_t	Backend vtable: an integrator's implementation of the timer service for a specific OS/RTOS/BSP target (ADR-005). Any slot may be NULL if that operation is unsupported by the backend, in which case the corresponding sapi_timer_* call returns SAPI_STATUS_NOT_SUPPORTED
Csapi_timer_config_t	Configuration for sapi_timer_create()
Csapi_vital_message_t	Vital channel message with integrated CRC-64
Csapi_voter_config_t	Configuration for sapi_voter_init()
Csapi_voter_storage_t	Storage for one voter instance (opaque to caller). No dynamic memory
Csapi_watchdog_config_t	Watchdog configuration
Csapi_watchdog_status_t	Watchdog health/status information
Csapi_watchdog_t	Watchdog handle (opaque)