diff --git a/index-scheduler/src/batch.rs b/index-scheduler/src/batch.rs
index 7ef056362..ff1281f8b 100644
--- a/index-scheduler/src/batch.rs
+++ b/index-scheduler/src/batch.rs
@@ -2,7 +2,8 @@ use crate::{
     task::{KindWithContent, Status},
     Error, IndexScheduler, Result, TaskId,
 };
-use milli::heed::RoTxn;
+use milli::{heed::RoTxn, update::IndexDocumentsMethod};
+use uuid::Uuid;
 
 use crate::{task::Kind, Task};
 
@@ -10,9 +11,53 @@ pub(crate) enum Batch {
     Cancel(Task),
     Snapshot(Vec<Task>),
     Dump(Vec<Task>),
-    Contiguous { tasks: Vec<Task>, kind: Kind },
-    One(Task),
-    Empty,
+    DocumentAddition {
+        index_uid: String,
+        tasks: Vec<Task>,
+        primary_key: Option<String>,
+        content_files: Vec<Uuid>,
+    },
+}
+
+impl IndexScheduler {
+    /*
+    pub(crate) fn process_batch(&self, wtxn: &mut RwTxn, batch: Batch) -> Result<Vec<Task>> {
+        match batch {
+            Batch::DocumentAddition {
+                tasks,
+                primary_key,
+                content_files,
+                index_uid,
+            } => {
+                let index = self.create_index(wtxn, &index_uid)?;
+                let ret = index.update_documents(
+                    IndexDocumentsMethod::UpdateDocuments,
+                    primary_key,
+                    self.file_store,
+                    content_files,
+                )?;
+
+                assert_eq!(ret.len(), tasks.len(), "Update documents must return the same number of `Result` than the number of tasks.");
+
+                Ok(tasks
+                    .into_iter()
+                    .zip(ret)
+                    .map(|(mut task, res)| match res {
+                        Ok(info) => {
+                            task.status = Status::Succeeded;
+                            task.info = Some(info.to_string());
+                        }
+                        Err(error) => {
+                            task.status = Status::Failed;
+                            task.error = Some(error.to_string());
+                        }
+                    })
+                    .collect())
+            }
+            _ => unreachable!(),
+        }
+    }
+    */
 }
 
 impl IndexScheduler {
@@ -21,7 +66,7 @@ impl IndexScheduler {
     /// 2. We get the *next* snapshot to process.
     /// 3. We get the *next* dump to process.
     /// 4. We get the *next* tasks to process for a specific index.
-    pub(crate) fn get_next_batch(&self, rtxn: &RoTxn) -> Result<Batch> {
+    pub(crate) fn create_next_batch(&self, rtxn: &RoTxn) -> Result<Batch> {
         let enqueued = &self.get_status(rtxn, Status::Enqueued)?;
         let to_cancel = self.get_kind(rtxn, Kind::CancelTask)? & enqueued;
 
@@ -122,3 +167,233 @@ impl Batch {
         }
     }
 }
+
+pub(crate) enum BatchKind {
+    ClearAll {
+        ids: Vec<TaskId>,
+    },
+    DocumentAddition {
+        addition_ids: Vec<TaskId>,
+    },
+    DocumentDeletion {
+        deletion_ids: Vec<TaskId>,
+    },
+    ClearAllAndSettings {
+        other: Vec<TaskId>,
+        settings_ids: Vec<TaskId>,
+    },
+    SettingsAndDocumentAddition {
+        settings_ids: Vec<TaskId>,
+        addition_ids: Vec<TaskId>,
+    },
+    Settings {
+        settings_ids: Vec<TaskId>,
+    },
+    DeleteIndex {
+        ids: Vec<TaskId>,
+    },
+    CreateIndex {
+        id: TaskId,
+    },
+    SwapIndex {
+        id: TaskId,
+    },
+    RenameIndex {
+        id: TaskId,
+    },
+}
+
+impl BatchKind {
+    /// return true if you must stop right there.
+    pub fn new(task_id: TaskId, kind: Kind) -> (Self, bool) {
+        match kind {
+            Kind::CreateIndex => (BatchKind::CreateIndex { id: task_id }, true),
+            Kind::DeleteIndex => (BatchKind::DeleteIndex { ids: vec![task_id] }, true),
+            Kind::RenameIndex => (BatchKind::RenameIndex { id: task_id }, true),
+            Kind::SwapIndex => (BatchKind::SwapIndex { id: task_id }, true),
+            Kind::ClearAllDocuments => (BatchKind::ClearAll { ids: vec![task_id] }, false),
+            Kind::DocumentAddition => (
+                BatchKind::DocumentAddition {
+                    addition_ids: vec![task_id],
+                },
+                false,
+            ),
+            Kind::DocumentDeletion => (
+                BatchKind::DocumentDeletion {
+                    deletion_ids: vec![task_id],
+                },
+                false,
+            ),
+            Kind::Settings => (
+                BatchKind::Settings {
+                    settings_ids: vec![task_id],
+                },
+                false,
+            ),
+
+            Kind::DumpExport | Kind::Snapshot | Kind::CancelTask => unreachable!(),
+        }
+    }
+
+    /// Return true if you must stop.
+    fn accumulate(&mut self, id: TaskId, kind: Kind) -> bool {
+        match (self, kind) {
+            // must handle the deleteIndex
+            (_, Kind::CreateIndex | Kind::RenameIndex | Kind::SwapIndex) => true,
+
+            (BatchKind::ClearAll { ids }, Kind::ClearAllDocuments | Kind::DocumentDeletion) => {
+                ids.push(id);
+                false
+            }
+            (BatchKind::ClearAll { .. }, Kind::DocumentAddition | Kind::Settings) => true,
+            (BatchKind::DocumentAddition { addition_ids }, Kind::ClearAllDocuments) => {
+                addition_ids.push(id);
+                *self = BatchKind::ClearAll {
+                    ids: addition_ids.clone(),
+                };
+                false
+            }
+
+            (BatchKind::DocumentAddition { addition_ids }, Kind::DocumentAddition) => {
+                addition_ids.push(id);
+                false
+            }
+            (BatchKind::DocumentAddition { .. }, Kind::DocumentDeletion) => true,
+            (BatchKind::DocumentAddition { addition_ids }, Kind::Settings) => {
+                *self = BatchKind::SettingsAndDocumentAddition {
+                    settings_ids: vec![id],
+                    addition_ids: addition_ids.clone(),
+                };
+                false
+            }
+
+            (BatchKind::DocumentDeletion { deletion_ids }, Kind::ClearAllDocuments) => {
+                deletion_ids.push(id);
+                *self = BatchKind::ClearAll {
+                    ids: deletion_ids.clone(),
+                };
+                false
+            }
+            (BatchKind::DocumentDeletion { .. }, Kind::DocumentAddition) => true,
+            (BatchKind::DocumentDeletion { deletion_ids }, Kind::DocumentDeletion) => {
+                deletion_ids.push(id);
+                false
+            }
+            (BatchKind::DocumentDeletion { .. }, Kind::Settings) => true,
+
+            (BatchKind::Settings { settings_ids }, Kind::ClearAllDocuments) => {
+                *self = BatchKind::ClearAllAndSettings {
+                    settings_ids: settings_ids.clone(),
+                    other: vec![id],
+                };
+                false
+            }
+            (BatchKind::Settings { .. }, Kind::DocumentAddition) => true,
+            (BatchKind::Settings { .. }, Kind::DocumentDeletion) => true,
+            (BatchKind::Settings { settings_ids }, Kind::Settings) => {
+                settings_ids.push(id);
+                false
+            }
+
+            (
+                BatchKind::ClearAllAndSettings {
+                    other,
+                    settings_ids,
+                },
+                Kind::ClearAllDocuments,
+            ) => {
+                other.push(id);
+                false
+            }
+            (BatchKind::ClearAllAndSettings { .. }, Kind::DocumentAddition) => true,
+            (
+                BatchKind::ClearAllAndSettings {
+                    other,
+                    settings_ids,
+                },
+                Kind::DocumentDeletion,
+            ) => {
+                other.push(id);
+                false
+            }
+            (
+                BatchKind::ClearAllAndSettings {
+                    settings_ids,
+                    other,
+                },
+                Kind::Settings,
+            ) => {
+                settings_ids.push(id);
+                false
+            }
+            (
+                BatchKind::SettingsAndDocumentAddition {
+                    settings_ids,
+                    addition_ids,
+                },
+                Kind::ClearAllDocuments,
+            ) => {
+                addition_ids.push(id);
+                *self = BatchKind::ClearAllAndSettings {
+                    settings_ids: settings_ids.clone(),
+                    other: addition_ids.clone(),
+                };
+                false
+            }
+            (
+                BatchKind::SettingsAndDocumentAddition {
+                    settings_ids,
+                    addition_ids,
+                },
+                Kind::DocumentAddition,
+            ) => {
+                addition_ids.push(id);
+                false
+            }
+            (
+                BatchKind::SettingsAndDocumentAddition {
+                    settings_ids,
+                    addition_ids,
+                },
+                Kind::DocumentDeletion,
+            ) => true,
+            (
+                BatchKind::SettingsAndDocumentAddition {
+                    settings_ids,
+                    addition_ids,
+                },
+                Kind::Settings,
+            ) => {
+                settings_ids.push(id);
+                false
+            }
+            (_, Kind::CancelTask | Kind::DumpExport | Kind::Snapshot) => unreachable!(),
+            (
+                BatchKind::CreateIndex { .. }
+                | BatchKind::DeleteIndex { .. }
+                | BatchKind::SwapIndex { .. }
+                | BatchKind::RenameIndex { .. },
+                _,
+            ) => {
+                unreachable!()
+            }
+        }
+    }
+}
+
+pub fn autobatcher(enqueued: Vec<(TaskId, Kind)>) -> Option<BatchKind> {
+    let mut enqueued = enqueued.into_iter();
+    let (id, kind) = enqueued.next()?;
+    let (mut acc, is_finished) = BatchKind::new(id, kind);
+    if is_finished {
+        return Some(acc);
+    }
+
+    for (id, kind) in enqueued {
+        if acc.accumulate(id, kind) {
+            break;
+        }
+    }
+
+    Some(acc)
+}
diff --git a/index-scheduler/src/lib.rs b/index-scheduler/src/lib.rs
index 35caea8ac..5da767416 100644
--- a/index-scheduler/src/lib.rs
+++ b/index-scheduler/src/lib.rs
@@ -80,6 +80,10 @@ pub struct IndexScheduler {
 }
 
 impl IndexScheduler {
+    pub fn create_index(&self, rwtxn: &mut RwTxn, name: &str) -> Result<Index> {
+        todo!()
+    }
+
     /// Return the index corresponding to the name. If it wasn't opened before
     /// it'll be opened. But if it doesn't exist on disk it'll throw an
     /// `IndexNotFound` error.
@@ -226,6 +230,9 @@ impl IndexScheduler {
             let res = self.process_batch(&mut wtxn, &mut batch);
 
             // TODO: TAMO: do this later
+            // must delete the file on disk
+            // in case of error, must update the tasks with the error
+            // in case of « success » we must update all the task on disk
             // self.handle_batch_result(res);
 
             match wtxn.commit() {
diff --git a/index-scheduler/src/task.rs b/index-scheduler/src/task.rs
index 3fdc1c2c3..c7bead937 100644
--- a/index-scheduler/src/task.rs
+++ b/index-scheduler/src/task.rs
@@ -27,6 +27,9 @@ pub struct Task {
     #[serde(with = "time::serde::rfc3339::option")]
     pub finished_at: Option<OffsetDateTime>,
 
+    pub error: Option<String>,
+    pub info: Option<String>,
+
     pub status: Status,
     pub kind: KindWithContent,
 }
diff --git a/index-scheduler/src/utils.rs b/index-scheduler/src/utils.rs
index 99190e086..ca52de038 100644
--- a/index-scheduler/src/utils.rs
+++ b/index-scheduler/src/utils.rs
@@ -67,6 +67,8 @@ impl IndexScheduler {
             })?;
         }
 
+        // TODO: TAMO: update the task in `all_tasks`
+
         Ok(())
     }