@@ -706,6 +706,22 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/api/control/locations/{location_id}/targets/{target}/triggers/{trigger_id}/changes": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get: operations["listPersonTriggerChanges"];
+        put?: never;
+        post?: never;
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/api/control/locations/{location_id}/targets/{target}/triggers/{trigger_id}/ticks": {
         parameters: {
             query?: never;
@@ -1920,6 +1936,28 @@ export interface components {
             /** Format: uuid */
             principal_id: string;
         };
+        /** @description One operator change of a trigger, as a person reads it: what changed, who changed it, when and why. */
+        PersonTriggerChange: {
+            /** @description The audited actor, such as `principal:<id>` for a person. */
+            actor: string;
+            /** @description The person's name when the actor is a person who still exists. */
+            actor_name?: string | null;
+            change: components["schemas"]["TriggerChange"];
+            /**
+             * Format: uuid
+             * @description The change's own ID, as recorded in the security audit.
+             */
+            event_id: string;
+            /** Format: date-time */
+            occurred_at: string;
+            /** @description The operator's reason, with credential-shaped text redacted. */
+            reason: string;
+            /**
+             * Format: uuid
+             * @description The publication that was current when the change was made.
+             */
+            snapshot_id: string;
+        };
         /** @description A trigger as people list it, with its newest tick so a list needs no read per trigger. */
         PersonTriggerRecord: components["schemas"]["TriggerRecord"] & {
             latest_tick?: null | components["schemas"]["TickRecord"];
@@ -4509,6 +4547,55 @@ export interface operations {
             };
         };
     };
+    listPersonTriggerChanges: {
+        parameters: {
+            query?: {
+                /** @description Maximum recent changes; defaults to 100, capped at 1000 */
+                limit?: number;
+            };
+            header?: never;
+            path: {
+                location_id: string;
+                target: string;
+                trigger_id: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description Operator changes, newest first */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["PersonTriggerChange"][];
+                };
+            };
+            /** @description Session rejected */
+            401: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content?: never;
+            };
+            403: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["ApiErrorBody"];
+                };
+            };
+            /** @description Trigger not found for a person who may view the whole target */
+            404: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content?: never;
+            };
+        };
+    };
     listPersonTicks: {
         parameters: {
             query?: {
 
@@ -138,6 +138,10 @@ pub(crate) fn person_routes() -> Router<ControlStore> {
             "/api/control/locations/{location_id}/targets/{target}/triggers/{trigger_id}/ticks",
             get(crate::api::_helpers::resources::person_reads::ticks),
         )
+        .route(
+            "/api/control/locations/{location_id}/targets/{target}/triggers/{trigger_id}/changes",
+            get(crate::api::_helpers::resources::person_reads::trigger_changes),
+        )
         .route(
             "/api/control/locations/{location_id}/targets/{target}/snapshots",
             get(crate::api::_helpers::resources::person_reads::snapshots),
 
@@ -9,9 +9,12 @@ use crate::api::errors::ApiError;
 use crate::api::models::{ReadQuery, RunEventsQuery, RunNodePath, StatementSqlQuery};
 use crate::credentials::models::{AuditContext, AuthenticatedPerson, DefaultRole};
 use crate::declarations::main::list_person_jobs::list_person_jobs;
+use crate::declarations::main::list_person_trigger_changes::list_person_trigger_changes;
 use crate::declarations::main::list_person_triggers::list_person_triggers;
 use crate::declarations::main::read_person_job::read_person_job;
-use crate::declarations::models::{JobDetailRecord, JobRecord, PersonTriggerRecord};
+use crate::declarations::models::{
+    JobDetailRecord, JobRecord, PersonTriggerChange, PersonTriggerRecord,
+};
 use crate::platform::main::read_person_location_health::read_person_location_health;
 use crate::platform::main::read_person_problems::read_person_problems;
 use crate::platform::models::{LocationHealthObservation, PlatformProblems};
@@ -333,6 +336,37 @@ pub(crate) async fn ticks(
     .ok_or_else(|| not_found("trigger not found"))
 }
 
+#[utoipa::path(get, path = "/api/control/locations/{location_id}/targets/{target}/triggers/{trigger_id}/changes", operation_id = "listPersonTriggerChanges",
+    params(("location_id" = Uuid, Path), ("target" = String, Path), ("trigger_id" = Uuid, Path),
+        ("limit" = Option<u32>, Query, description = "Maximum recent changes; defaults to 100, capped at 1000")),
+    responses((status = 200, body = Vec<PersonTriggerChange>, description = "Operator changes, newest first"),
+        (status = 401, description = "Session rejected"),
+        (status = 403, body = crate::api::models::ApiErrorBody),
+        (status = 404, description = "Trigger not found for a person who may view the whole target")),
+    security(("session" = []), ("cliSession" = [])))]
+pub(crate) async fn trigger_changes(
+    (State(store), Extension(context)): (State<ControlStore>, Extension<AuditContext>),
+    Extension(default_role): Extension<DefaultRole>,
+    (Path((location_id, target, trigger_id)), Query(options)): (
+        Path<(Uuid, String, Uuid)>,
+        Query<ReadQuery>,
+    ),
+    Extension(AuthenticatedPerson(principal, _)): Extension<AuthenticatedPerson>,
+) -> Result<Json<Vec<PersonTriggerChange>>, ApiError> {
+    list_person_trigger_changes(
+        &store,
+        (&context, principal),
+        (
+            (location_id, &target),
+            (trigger_id, options.limit.unwrap_or(100)),
+        ),
+        default_role,
+    )
+    .await?
+    .map(Json)
+    .ok_or_else(|| not_found("trigger not found"))
+}
+
 #[utoipa::path(get, path = "/api/control/locations/{location_id}/targets/{target}/snapshots", operation_id = "listPersonSnapshots",
     params(("location_id" = Uuid, Path), ("target" = String, Path),
         ("limit" = Option<u32>, Query, description = "Maximum recent publications; defaults to 20, capped at 100")),
 
@@ -37,6 +37,7 @@ use crate::api::_helpers::resources::{
     person_reads::job,
     person_reads::triggers,
     person_reads::ticks,
+    person_reads::trigger_changes,
     person_reads::snapshots,
     person_reads::health,
     person_reads::problems,
 
@@ -1,16 +1,29 @@
-//! Whether a run or trigger, including a removed trigger, belongs to one location and target.
+//! A person reads one run or trigger, including a removed trigger, only with view on the whole target.
 
 use uuid::Uuid;
 
+use crate::authorization::main::authorize_listing::authorize_listing;
+use crate::credentials::models::{AuditContext, DefaultRole};
 use crate::store::errors::ControlError;
-use crate::store::main::query::query;
-use crate::store::models::{ControlTransaction, Parameter, TargetRow};
+use crate::store::main::{begin::begin, commit::commit, query::query};
+use crate::store::models::{
+    ControlStore, ControlTransaction, Parameter, TargetRow, TransactionMode,
+};
 
+/// Authorizes first, then `None` (after committing) when the row is not in this location and target.
 pub(crate) async fn row_in_target(
-    transaction: ControlTransaction,
-    (location_id, target): (Uuid, &str),
-    row: TargetRow,
-) -> Result<(ControlTransaction, bool), ControlError> {
+    store: &ControlStore,
+    credentials: (&AuditContext, Uuid),
+    ((location_id, target), row): ((Uuid, &str), TargetRow),
+    default_role: DefaultRole,
+) -> Result<Option<ControlTransaction>, ControlError> {
+    let (transaction, _) = authorize_listing(
+        begin(store, TransactionMode::Write).await?,
+        credentials,
+        (location_id, target),
+        default_role,
+    )
+    .await?;
     let (sql, id) = match row {
         TargetRow::Run(run_id) => (
             "SELECT run_id FROM sqb_runs WHERE run_id=$1 AND location_id=$2 AND target=$3",
@@ -31,5 +44,9 @@ pub(crate) async fn row_in_target(
         ],
     )
     .await?;
-    Ok((transaction, !rows.is_empty()))
+    if rows.is_empty() {
+        commit(transaction).await?;
+        return Ok(None);
+    }
+    Ok(Some(transaction))
 }
@@ -2,9 +2,14 @@
 
 use uuid::Uuid;
 
-use crate::declarations::models::{JobRecord, StoredJob, TriggerRecord};
+use sqlbuild_core::redaction::main::redact_text::redact_text;
+
+use crate::declarations::models::{
+    JobRecord, PersonTriggerChange, StoredJob, TriggerChangeRequest, TriggerRecord,
+};
 use crate::scheduler::models::TickRecord;
 use crate::store::errors::ControlError;
+use crate::store::main::query::query;
 use crate::store::main::query_records::query_records;
 use crate::store::models::{ControlTransaction, Parameter};
 
@@ -19,6 +24,48 @@ pub(crate) async fn triggers_in(
         vec![Parameter::Id(location_id), Parameter::Text(target.into())]).await
 }
 
+/// A trigger's operator changes from the security audit, newest first, with a person actor's name.
+pub(crate) async fn trigger_changes_in(
+    transaction: ControlTransaction,
+    trigger_id: Uuid,
+    limit: u32,
+) -> Result<(ControlTransaction, Vec<PersonTriggerChange>), ControlError> {
+    let (transaction, rows) = query(
+        transaction,
+        "SELECT a.scope_json, a.occurred_at, p.name AS actor_name FROM sqb_security_audit a \
+         LEFT JOIN sqb_principals p ON 'principal:' || CAST(p.principal_id AS TEXT)=a.actor \
+         WHERE a.action='trigger.changed' AND a.scope_json ->> 'trigger_id'=$1 \
+         ORDER BY a.occurred_at DESC, a.event_id DESC LIMIT $2",
+        vec![
+            Parameter::Text(trigger_id.to_string()),
+            Parameter::Integer(i64::from(limit.min(1000))),
+        ],
+    )
+    .await?;
+    let changes = rows
+        .into_iter()
+        .map(|row| {
+            let request: TriggerChangeRequest =
+                serde_json::from_value(row["scope_json"]["request"].clone())
+                    .map_err(|error| ControlError::Schema(format!("trigger change: {error}")))?;
+            let snapshot_id = serde_json::from_value(row["scope_json"]["snapshot_id"].clone())
+                .map_err(|error| ControlError::Schema(format!("trigger change: {error}")))?;
+            let occurred_at = serde_json::from_value(row["occurred_at"].clone())
+                .map_err(|error| ControlError::Schema(format!("trigger change: {error}")))?;
+            Ok(PersonTriggerChange {
+                event_id: request.event_id,
+                change: request.change,
+                actor: request.actor,
+                actor_name: row["actor_name"].as_str().map(str::to_owned),
+                reason: redact_text(&request.reason),
+                occurred_at,
+                snapshot_id,
+            })
+        })
+        .collect::<Result<_, ControlError>>()?;
+    Ok((transaction, changes))
+}
+
 pub(crate) async fn jobs_in(
     transaction: ControlTransaction,
     (location_id, target): (Uuid, &str),
 
@@ -0,0 +1,33 @@
+//! A person sees a trigger's on/off history only with view on every current node; an unknown trigger is refused alike.
+
+use uuid::Uuid;
+
+use crate::authorization::main::row_in_target::row_in_target;
+use crate::credentials::models::{AuditContext, DefaultRole};
+use crate::declarations::_helpers::reads::trigger_changes_in;
+use crate::declarations::models::PersonTriggerChange;
+use crate::store::errors::ControlError;
+use crate::store::main::commit::commit;
+use crate::store::models::{ControlStore, TargetRow};
+
+/// `None` when the trigger is not in this location and target; authorization runs first either way.
+pub async fn list_person_trigger_changes(
+    store: &ControlStore,
+    (context, credentials): (&AuditContext, Uuid),
+    ((location_id, target), (trigger_id, limit)): ((Uuid, &str), (Uuid, u32)),
+    default_role: DefaultRole,
+) -> Result<Option<Vec<PersonTriggerChange>>, ControlError> {
+    let Some(transaction) = row_in_target(
+        store,
+        (context, credentials),
+        ((location_id, target), TargetRow::Trigger(trigger_id)),
+        default_role,
+    )
+    .await?
+    else {
+        return Ok(None);
+    };
+    let (transaction, changes) = trigger_changes_in(transaction, trigger_id, limit).await?;
+    commit(transaction).await?;
+    Ok(Some(changes))
+}
@@ -3,6 +3,7 @@ pub mod change_trigger;
 pub(crate) mod frozen_definitions;
 pub mod group_dependencies;
 pub mod list_person_jobs;
+pub mod list_person_trigger_changes;
 pub mod list_person_triggers;
 pub mod list_trigger_events;
 pub mod list_triggers;
 
@@ -153,6 +153,23 @@ pub struct PersonTriggerRecord {
     pub latest_tick: Option<crate::scheduler::models::TickRecord>,
 }
 
+/// One operator change of a trigger, as a person reads it: what changed, who changed it, when and why.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, utoipa::ToSchema)]
+pub struct PersonTriggerChange {
+    /// The change's own ID, as recorded in the security audit.
+    pub event_id: uuid::Uuid,
+    pub change: TriggerChange,
+    /// The audited actor, such as `principal:<id>` for a person.
+    pub actor: String,
+    /// The person's name when the actor is a person who still exists.
+    pub actor_name: Option<String>,
+    /// The operator's reason, with credential-shaped text redacted.
+    pub reason: String,
+    pub occurred_at: DateTime<Utc>,
+    /// The publication that was current when the change was made.
+    pub snapshot_id: uuid::Uuid,
+}
+
 /// Operator changes are immutable facts; clearing an override restores the published code default.
 #[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, utoipa::ToSchema)]
 #[serde(tag = "kind", rename_all = "snake_case", deny_unknown_fields)]