diff --git a/CHANGELOG.md b/CHANGELOG.md
index 55003170263..c5ca51d4dcb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,9 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### Deprecations
 
+* `split.legacy-bookmark-behavior` is now deprecated in favor of
+  `split.identity-strategy`.
+
 ### New features
 
 * `jj bisect` will now mention when it cannot unambiguously find the first bad
@@ -30,6 +33,11 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
   back to prompting the user if the heuristics are inconclusive. It can also run
   in non-interactive mode, which aborts if prompting would be needed.
 
+* Added `split.identity-strategy` configuration setting to control which commit
+  inherits the original Change ID and where bookmarks move after `jj split`.
+  Supported strategies are `"selected"`, `"remaining"` (default), and
+  `"follow-description"`.
+
 ### Fixed bugs
 
 * The default pager flags now include `-K` (`--quit-on-intr`), so pressing
diff --git a/cli/src/commands/split.rs b/cli/src/commands/split.rs
index 4da3cc5f66f..2c50c5a39d1 100644
--- a/cli/src/commands/split.rs
+++ b/cli/src/commands/split.rs
@@ -18,6 +18,8 @@ use clap_complete::ArgValueCandidates;
 use clap_complete::ArgValueCompleter;
 use jj_lib::backend::CommitId;
 use jj_lib::commit::Commit;
+use jj_lib::commit_builder::DetachedCommitBuilder;
+use jj_lib::config::ConfigGetResultExt as _;
 use jj_lib::matchers::Matcher;
 use jj_lib::merge::Diff;
 use jj_lib::merge::Merge;
@@ -32,6 +34,7 @@ use jj_lib::rewrite::RebaseOptions;
 use jj_lib::rewrite::RebasedCommit;
 use jj_lib::rewrite::RewriteRefsOptions;
 use jj_lib::rewrite::move_commits;
+use jj_lib::settings::UserSettings;
 use tracing::instrument;
 
 use crate::cli_util::CommandHelper;
@@ -42,7 +45,9 @@ use crate::cli_util::WorkspaceCommandTransaction;
 use crate::cli_util::compute_commit_location;
 use crate::cli_util::print_unmatched_explicit_paths;
 use crate::command_error::CommandError;
+use crate::command_error::user_error;
 use crate::complete;
+use crate::description_util::TextEditor;
 use crate::description_util::add_trailers;
 use crate::description_util::description_template;
 use crate::description_util::edit_description;
@@ -292,107 +297,116 @@ pub(crate) async fn cmd_split(
     // Prompt the user to select the changes they want for the first commit.
     let target = select_diff(ui, &tx, &target_commit, &matcher, &diff_selector).await?;
 
-    // Create the first commit, which includes the changes selected by the user.
-    let first_commit = {
-        let mut commit_builder = tx.repo_mut().rewrite_commit(&target.commit).detach();
-        commit_builder.set_tree(target.selected_tree.clone());
-        if use_move_flags {
-            commit_builder.clear_rewrite_source();
-            // Generate a new change id so that the commit being split doesn't
-            // become divergent.
-            commit_builder.generate_new_change_id();
-        }
-        let use_editor = args.message_paragraphs.is_none() || args.editor;
-        let description = match &args.message_paragraphs {
-            Some(paragraphs) => join_message_paragraphs(paragraphs),
-            None => commit_builder.description().to_owned(),
-        };
-        // The first trailer would become the first line of the description.
-        // Also, a commit with no description is treated in a special way in
-        // jujutsu: it can be discarded as soon as it's no longer the working
-        // copy. Adding a trailer to an empty description would break that
-        // logic.
-        let description = if !description.is_empty() || use_editor {
-            commit_builder.set_description(description);
-            add_trailers(ui, &tx, &commit_builder).await?
-        } else {
-            description
-        };
-        let description = if use_editor {
-            commit_builder.set_description(description);
-            let temp_commit = commit_builder.write_hidden().await?;
-            let intro = "Enter a description for the selected changes.";
-            let template = description_template(ui, &tx, intro, &temp_commit)?;
-            edit_description(&text_editor, &template)?
-        } else {
-            description
-        };
-        commit_builder.set_description(description);
-        commit_builder.write(tx.repo_mut()).await?
+    let target_tree = target.commit.tree();
+    let second_tree = if parallel {
+        // Merge the original commit tree with its parent using the tree
+        // containing the user selected changes as the base for the merge.
+        // This results in a tree with the changes the user didn't select.
+        let selected_diff = target
+            .diff_with_labels(
+                "parents of split revision",
+                "selected changes for split",
+                "split revision",
+            )
+            .await?;
+        MergedTree::merge(Merge::from_diffs(
+            (
+                target_tree,
+                format!("split revision ({})", target.commit.conflict_label()),
+            ),
+            [selected_diff.invert()],
+        ))
+        .await?
+    } else {
+        target_tree
     };
 
-    // Create the second commit, which includes everything the user didn't
-    // select.
-    let second_commit = {
-        let target_tree = target.commit.tree();
-        let new_tree = if parallel {
-            // Merge the original commit tree with its parent using the tree
-            // containing the user selected changes as the base for the merge.
-            // This results in a tree with the changes the user didn't select.
-            let selected_diff = target
-                .diff_with_labels(
-                    "parents of split revision",
-                    "selected changes for split",
-                    "split revision",
-                )
-                .await?;
-            MergedTree::merge(Merge::from_diffs(
-                (
-                    target_tree,
-                    format!("split revision ({})", target.commit.conflict_label()),
-                ),
-                [selected_diff.invert()],
-            ))
-            .await?
-        } else {
-            target_tree
-        };
-        let parents = if parallel {
-            target.commit.parent_ids().to_vec()
-        } else {
-            vec![first_commit.id().clone()]
-        };
-        let mut commit_builder = tx.repo_mut().rewrite_commit(&target.commit).detach();
-        commit_builder.set_parents(parents).set_tree(new_tree);
-        let mut show_editor = args.editor;
-        if !use_move_flags {
-            commit_builder.clear_rewrite_source();
-            // Generate a new change id so that the commit being split doesn't
-            // become divergent.
-            commit_builder.generate_new_change_id();
-        }
-        let description = if target.commit.description().is_empty() {
-            // If there was no description before, don't ask for one for the
-            // second commit.
-            "".to_string()
-        } else {
-            show_editor = show_editor || args.message_paragraphs.is_none();
-            // Just keep the original message unchanged
-            commit_builder.description().to_owned()
-        };
-        let description = if show_editor {
-            let new_description = add_trailers(ui, &tx, &commit_builder).await?;
-            commit_builder.set_description(new_description);
-            let temp_commit = commit_builder.write_hidden().await?;
-            let intro = "Enter a description for the remaining changes.";
-            let template = description_template(ui, &tx, intro, &temp_commit)?;
-            edit_description(&text_editor, &template)?
-        } else {
-            description
-        };
-        commit_builder.set_description(description);
-        commit_builder.write(tx.repo_mut()).await?
+    // Tentatively determine which commit will inherit the original change ID.
+    // This might change if follow-description is configured, but it prevents us
+    // from showing change IDs in the editor that are guaranteed to be wrong.
+    let strategies = load_identity_strategies(tx.settings())?;
+    let tentative_recipient = find_static_identity_recipient(&strategies);
+
+    let mut first_commit_builder = tx.repo_mut().rewrite_commit(&target.commit).detach();
+    first_commit_builder.set_tree(target.selected_tree.clone());
+    if tentative_recipient == IdentityRecipient::Remaining {
+        first_commit_builder.clear_rewrite_source();
+        // Generate a new change id so that the commit being split doesn't
+        // become divergent.
+        first_commit_builder.generate_new_change_id();
+    }
+    let first_description =
+        resolve_first_description(ui, &mut tx, &text_editor, &mut first_commit_builder, args)
+            .await?;
+    first_commit_builder.set_description(&first_description);
+
+    let parents = if parallel {
+        target.commit.parent_ids().to_vec()
+    } else {
+        let temp_first = first_commit_builder.write_hidden().await?;
+        vec![temp_first.id().clone()]
     };
+    let mut second_commit_builder = tx.repo_mut().rewrite_commit(&target.commit).detach();
+    second_commit_builder
+        .set_parents(parents)
+        .set_tree(second_tree.clone());
+    if tentative_recipient == IdentityRecipient::Selected {
+        second_commit_builder.clear_rewrite_source();
+        // Generate a new change id so that the commit being split doesn't
+        // become divergent.
+        second_commit_builder.generate_new_change_id();
+    }
+    let second_description = resolve_second_description(
+        ui,
+        &mut tx,
+        &text_editor,
+        &mut second_commit_builder,
+        &target.commit,
+        args,
+    )
+    .await?;
+    second_commit_builder.set_description(&second_description);
+
+    let identity_recipient = resolve_identity_recipient(
+        &strategies,
+        &target,
+        &first_description,
+        &second_description,
+    );
+
+    if identity_recipient != tentative_recipient {
+        match identity_recipient {
+            IdentityRecipient::Selected => {
+                first_commit_builder = tx.repo_mut().rewrite_commit(&target.commit).detach();
+                first_commit_builder.set_tree(target.selected_tree.clone());
+                first_commit_builder.set_description(first_description);
+
+                second_commit_builder.clear_rewrite_source();
+                // Generate a new change id so that the commit being split doesn't
+                // become divergent.
+                second_commit_builder.generate_new_change_id();
+            }
+            IdentityRecipient::Remaining => {
+                first_commit_builder.clear_rewrite_source();
+                // Generate a new change id so that the commit being split doesn't
+                // become divergent.
+                first_commit_builder.generate_new_change_id();
+
+                let parents = second_commit_builder.parents().to_vec();
+                second_commit_builder = tx.repo_mut().rewrite_commit(&target.commit).detach();
+                second_commit_builder
+                    .set_parents(parents)
+                    .set_tree(second_tree);
+                second_commit_builder.set_description(second_description);
+            }
+        }
+    }
+
+    let first_commit = first_commit_builder.write(tx.repo_mut()).await?;
+    if !parallel {
+        second_commit_builder.set_parents(vec![first_commit.id().clone()]);
+    }
+    let second_commit = second_commit_builder.write(tx.repo_mut()).await?;
 
     let (first_commit, second_commit, num_rebased) = if use_move_flags {
         move_first_commit(
@@ -405,7 +419,15 @@ pub(crate) async fn cmd_split(
         )
         .await?
     } else {
-        rewrite_descendants(&mut tx, &target, first_commit, second_commit, parallel).await?
+        rewrite_descendants(
+            &mut tx,
+            &target,
+            first_commit,
+            second_commit,
+            parallel,
+            identity_recipient,
+        )
+        .await?
     };
     if let Some(mut formatter) = ui.status_formatter() {
         if num_rebased > 0 {
@@ -500,9 +522,9 @@ async fn rewrite_descendants(
     first_commit: Commit,
     second_commit: Commit,
     parallel: bool,
+    identity_recipient: IdentityRecipient,
 ) -> Result<(Commit, Commit, usize), CommandError> {
-    let legacy_bookmark_behavior = tx.settings().get_bool("split.legacy-bookmark-behavior")?;
-    if legacy_bookmark_behavior {
+    if identity_recipient == IdentityRecipient::Remaining {
         // Mark the commit being split as rewritten to the second commit. This
         // moves any bookmarks pointing to the target commit to the second
         // commit.
@@ -515,7 +537,7 @@ async fn rewrite_descendants(
             vec![target.commit.id().clone()],
             async |mut rewriter: CommitRewriter<'_>| {
                 num_rebased += 1;
-                if parallel && legacy_bookmark_behavior {
+                if parallel && identity_recipient == IdentityRecipient::Remaining {
                     // The old_parent is the second commit due to the rewrite above.
                     rewriter.replace_parent(
                         second_commit.id(),
@@ -598,3 +620,147 @@ The changes that are not selected will replace the original commit.
 
     Ok(selection)
 }
+
+async fn resolve_first_description(
+    ui: &Ui,
+    tx: &mut WorkspaceCommandTransaction<'_>,
+    text_editor: &TextEditor,
+    commit_builder: &mut DetachedCommitBuilder,
+    args: &SplitArgs,
+) -> Result<String, CommandError> {
+    let use_editor = args.message_paragraphs.is_none() || args.editor;
+    let description = match &args.message_paragraphs {
+        Some(paragraphs) => join_message_paragraphs(paragraphs),
+        None => commit_builder.description().to_owned(),
+    };
+    let description = if !description.is_empty() || use_editor {
+        commit_builder.set_description(description);
+        add_trailers(ui, tx, commit_builder).await?
+    } else {
+        description
+    };
+    let description = if use_editor {
+        commit_builder.set_description(&description);
+        let temp_commit = commit_builder.write_hidden().await?;
+        let intro = "Enter a description for the selected changes.";
+        let template = description_template(ui, tx, intro, &temp_commit)?;
+        edit_description(text_editor, &template)?
+    } else {
+        description
+    };
+    Ok(description)
+}
+
+async fn resolve_second_description(
+    ui: &Ui,
+    tx: &mut WorkspaceCommandTransaction<'_>,
+    text_editor: &TextEditor,
+    commit_builder: &mut DetachedCommitBuilder,
+    target_commit: &Commit,
+    args: &SplitArgs,
+) -> Result<String, CommandError> {
+    let mut show_editor = args.editor;
+    let description = if target_commit.description().is_empty() {
+        "".to_string()
+    } else {
+        show_editor = show_editor || args.message_paragraphs.is_none();
+        commit_builder.description().to_owned()
+    };
+    let description = if show_editor {
+        let new_description = if !description.is_empty() {
+            commit_builder.set_description(description);
+            add_trailers(ui, tx, commit_builder).await?
+        } else {
+            description
+        };
+        commit_builder.set_description(new_description);
+        let temp_commit = commit_builder.write_hidden().await?;
+        let intro = "Enter a description for the remaining changes.";
+        let template = description_template(ui, tx, intro, &temp_commit)?;
+        edit_description(text_editor, &template)?
+    } else {
+        description
+    };
+    Ok(description)
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(crate) enum IdentityRecipient {
+    Selected,
+    Remaining,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(crate) enum IdentityStrategy {
+    Selected,
+    Remaining,
+    FollowDescription,
+}
+
+impl IdentityStrategy {
+    fn from_str(s: &str) -> Result<Self, CommandError> {
+        match s {
+            "selected" => Ok(Self::Selected),
+            "remaining" => Ok(Self::Remaining),
+            "follow-description" => Ok(Self::FollowDescription),
+            other => Err(user_error(format!("Invalid identity strategy `{other}`."))),
+        }
+    }
+}
+
+fn load_identity_strategies(
+    settings: &UserSettings,
+) -> Result<Vec<IdentityStrategy>, CommandError> {
+    let raw_strategies: Vec<String> =
+        if let Ok(list) = settings.get::<Vec<String>>("split.identity-strategy") {
+            list
+        } else if let Some(single) = settings.get_string("split.identity-strategy").optional()? {
+            vec![single]
+        } else {
+            vec!["remaining".to_string()]
+        };
+
+    raw_strategies
+        .iter()
+        .map(|s| IdentityStrategy::from_str(s))
+        .collect()
+}
+
+fn find_static_identity_recipient(strategies: &[IdentityStrategy]) -> IdentityRecipient {
+    for strategy in strategies {
+        match strategy {
+            IdentityStrategy::Selected => return IdentityRecipient::Selected,
+            IdentityStrategy::Remaining => return IdentityRecipient::Remaining,
+            IdentityStrategy::FollowDescription => {}
+        }
+    }
+    IdentityRecipient::Remaining
+}
+
+fn resolve_identity_recipient(
+    strategies: &[IdentityStrategy],
+    target: &CommitWithSelection,
+    first_description: &str,
+    second_description: &str,
+) -> IdentityRecipient {
+    for strategy in strategies {
+        match strategy {
+            IdentityStrategy::Selected => return IdentityRecipient::Selected,
+            IdentityStrategy::Remaining => return IdentityRecipient::Remaining,
+            IdentityStrategy::FollowDescription => {
+                let orig_desc = target.commit.description();
+                if !orig_desc.is_empty() {
+                    let first_matches = first_description == orig_desc;
+                    let second_matches = second_description == orig_desc;
+                    match (first_matches, second_matches) {
+                        (true, false) => return IdentityRecipient::Selected,
+                        (false, true) => return IdentityRecipient::Remaining,
+                        _ => {} // Ambiguous or both edited; yield to next strategy in chain
+                    }
+                }
+            }
+        }
+    }
+
+    IdentityRecipient::Remaining
+}
diff --git a/cli/src/config-schema.json b/cli/src/config-schema.json
index 4ff0790b875..9acd00681d1 100644
--- a/cli/src/config-schema.json
+++ b/cli/src/config-schema.json
@@ -1047,10 +1047,20 @@
             "type": "object",
             "description": "Settings for jj split",
             "properties": {
-                "legacy-bookmark-behavior": {
-                    "type": "boolean",
-                    "description": "If true, bookmarks will move to the second commit instead of the first.",
-                    "default": true
+                "identity-strategy": {
+                    "type": "array",
+                    "description": "The strategy chain to determine Change ID and bookmark assignment after split",
+                    "items": {
+                        "type": "string",
+                        "enum": [
+                            "selected",
+                            "remaining",
+                            "follow-description"
+                        ]
+                    },
+                    "default": [
+                        "remaining"
+                    ]
                 }
             }
         },
diff --git a/cli/src/config.rs b/cli/src/config.rs
index a4d82d964d1..52932e93402 100644
--- a/cli/src/config.rs
+++ b/cli/src/config.rs
@@ -877,7 +877,18 @@ fn parse_config_arg_item(item_str: &str) -> Result<(ConfigNamePathBuf, ConfigVal
 
 /// List of rules to migrate deprecated config variables.
 pub fn default_config_migrations() -> Vec<ConfigMigrationRule> {
-    vec![]
+    vec![
+        // TODO: Delete in jj 0.50.0+
+        ConfigMigrationRule::rename_update_value(
+            "split.legacy-bookmark-behavior",
+            "split.identity-strategy",
+            |old_value| {
+                let boolean = old_value.as_bool().ok_or("expected a boolean")?;
+                let strategy = if boolean { "remaining" } else { "selected" };
+                Ok(ConfigValue::from_iter([strategy]))
+            },
+        ),
+    ]
 }
 
 /// Command name and arguments specified by config.
diff --git a/cli/src/config/misc.toml b/cli/src/config/misc.toml
index 70ed210c17e..1228a6d06e6 100644
--- a/cli/src/config/misc.toml
+++ b/cli/src/config/misc.toml
@@ -61,8 +61,5 @@ max-new-file-size = "1MiB"
 auto-track = "all()"
 auto-update-stale = false
 
-# TODO: https://github.com/jj-vcs/jj/issues/3419 - Remove when fully deprecated.
-# The behavior when this flag is set to false is experimental and may be changed
-# in the future.
 [split]
-legacy-bookmark-behavior = true
+identity-strategy = ["remaining"]
diff --git a/cli/tests/test_split_command.rs b/cli/tests/test_split_command.rs
index 9c9fd8c9a2e..26ad936aa08 100644
--- a/cli/tests/test_split_command.rs
+++ b/cli/tests/test_split_command.rs
@@ -83,10 +83,10 @@ fn test_split_by_paths() -> TestResult {
     ]);
     insta::assert_snapshot!(output, @"
     ------- stderr -------
-    Selected changes : qpvuntsm 6dbc7747 (no description set)
-    Remaining changes: zsuskuln 42cbbc02 (no description set)
-    Working copy  (@) now at: zsuskuln 42cbbc02 (no description set)
-    Parent commit (@-)      : qpvuntsm 6dbc7747 (no description set)
+    Selected changes : zsuskuln 8a73f71d (no description set)
+    Remaining changes: qpvuntsm c4d8ebac (no description set)
+    Working copy  (@) now at: qpvuntsm c4d8ebac (no description set)
+    Parent commit (@-)      : zsuskuln 8a73f71d (no description set)
     [EOF]
     ");
     // Trailers should be added to the editor template
@@ -97,7 +97,7 @@ fn test_split_by_paths() -> TestResult {
 
     Trailer: value
 
-    JJ: Change ID: qpvuntsm
+    JJ: Change ID: zsuskuln
     JJ: This commit contains the following changes:
     JJ:     A file2
     JJ:
@@ -106,8 +106,8 @@ fn test_split_by_paths() -> TestResult {
     assert!(!test_env.env_root().join("editor1").exists());
 
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  zsuskulnrvyr false
-    ○  qpvuntsmwlqt false
+    @  qpvuntsmwlqt false
+    ○  zsuskulnrvyr false
     ◆  zzzzzzzzzzzz true
     [EOF]
     ");
@@ -138,21 +138,21 @@ fn test_split_by_paths() -> TestResult {
     // Insert an empty commit after @- with "split ."
     std::fs::write(&edit_script, "")?;
     let output = work_dir.run_jj(["split", "-r", "@-", "."]);
-    insta::assert_snapshot!(output, @r"
+    insta::assert_snapshot!(output, @"
     ------- stderr -------
     Warning: All changes have been selected, so the original revision will become empty.
     Rebased 1 descendant commits.
-    Selected changes : qpvuntsm 9fd1c9e1 (no description set)
-    Remaining changes: znkkpsqq 41e0da21 (empty) (no description set)
-    Working copy  (@) now at: zsuskuln a06e40b8 (no description set)
-    Parent commit (@-)      : znkkpsqq 41e0da21 (empty) (no description set)
+    Selected changes : znkkpsqq d6e65134 (no description set)
+    Remaining changes: zsuskuln aa27eaa3 (empty) (no description set)
+    Working copy  (@) now at: qpvuntsm e94cab21 (no description set)
+    Parent commit (@-)      : zsuskuln aa27eaa3 (empty) (no description set)
     [EOF]
     ");
 
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  zsuskulnrvyr false
-    ○  znkkpsqqskkl true
-    ○  qpvuntsmwlqt false
+    @  qpvuntsmwlqt false
+    ○  zsuskulnrvyr true
+    ○  znkkpsqqskkl false
     ◆  zzzzzzzzzzzz true
     [EOF]
     ");
@@ -169,22 +169,22 @@ fn test_split_by_paths() -> TestResult {
     // Insert an empty commit before @- with "split nonexistent"
     std::fs::write(&edit_script, "")?;
     let output = work_dir.run_jj(["split", "-r", "@-", "nonexistent"]);
-    insta::assert_snapshot!(output, @r"
+    insta::assert_snapshot!(output, @"
     ------- stderr -------
     Warning: No matching entries for paths: nonexistent
     Warning: No changes have been selected, so the new revision will be empty.
     Rebased 1 descendant commits.
-    Selected changes : qpvuntsm 49416632 (empty) (no description set)
-    Remaining changes: lylxulpl 718afbf5 (no description set)
-    Working copy  (@) now at: zsuskuln 0ed53ee6 (no description set)
-    Parent commit (@-)      : lylxulpl 718afbf5 (no description set)
+    Selected changes : lylxulpl 3d639d71 (empty) (no description set)
+    Remaining changes: znkkpsqq 706a0e77 (no description set)
+    Working copy  (@) now at: qpvuntsm 502cf440 (no description set)
+    Parent commit (@-)      : znkkpsqq 706a0e77 (no description set)
     [EOF]
     ");
 
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  zsuskulnrvyr false
-    ○  lylxulplsnyw false
-    ○  qpvuntsmwlqt true
+    @  qpvuntsmwlqt false
+    ○  znkkpsqqskkl false
+    ○  lylxulplsnyw true
     ◆  zzzzzzzzzzzz true
     [EOF]
     ");
@@ -199,13 +199,13 @@ fn test_split_by_paths() -> TestResult {
     // Splitting a commit with deleted files should not show a warning.
     work_dir.remove_file("file1");
     let output = work_dir.run_jj(["split", "file1"]);
-    insta::assert_snapshot!(output, @r"
+    insta::assert_snapshot!(output, @"
     ------- stderr -------
     Warning: All changes have been selected, so the original revision will become empty.
-    Selected changes : uyznsvlq 971ccc0b (no description set)
-    Remaining changes: xznxytkn a267cd96 (empty) (no description set)
-    Working copy  (@) now at: smwtzssm 6715dc2c (empty) (no description set)
-    Parent commit (@-)      : uyznsvlq 971ccc0b (no description set)
+    Selected changes : xznxytkn e69850ba (no description set)
+    Remaining changes: uyznsvlq df0b606a (empty) (no description set)
+    Working copy  (@) now at: smwtzssm 6c647048 (empty) (no description set)
+    Parent commit (@-)      : xznxytkn e69850ba (no description set)
     [EOF]
     ");
     Ok(())
@@ -236,10 +236,10 @@ fn test_split_with_non_empty_description() -> TestResult {
     let output = work_dir.run_jj(["split", "file1"]);
     insta::assert_snapshot!(output, @"
     ------- stderr -------
-    Selected changes : qpvuntsm c7f7b14b part 1
-    Remaining changes: kkmpptxz ac33a5a9 part 2
-    Working copy  (@) now at: kkmpptxz ac33a5a9 part 2
-    Parent commit (@-)      : qpvuntsm c7f7b14b part 1
+    Selected changes : kkmpptxz 530f78ed part 1
+    Remaining changes: qpvuntsm 88189e08 part 2
+    Working copy  (@) now at: qpvuntsm 88189e08 part 2
+    Parent commit (@-)      : kkmpptxz 530f78ed part 1
     [EOF]
     ");
 
@@ -248,7 +248,7 @@ fn test_split_with_non_empty_description() -> TestResult {
     JJ: Enter a description for the selected changes.
     test
 
-    JJ: Change ID: qpvuntsm
+    JJ: Change ID: kkmpptxz
     JJ: This commit contains the following changes:
     JJ:     A file1
     JJ:
@@ -259,15 +259,15 @@ fn test_split_with_non_empty_description() -> TestResult {
     JJ: Enter a description for the remaining changes.
     test
 
-    JJ: Change ID: kkmpptxz
+    JJ: Change ID: qpvuntsm
     JJ: This commit contains the following changes:
     JJ:     A file2
     JJ:
     JJ: Lines starting with "JJ:" (like this one) will be removed.
     "#);
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  kkmpptxzrspx false part 2
-    ○  qpvuntsmwlqt false part 1
+    @  qpvuntsmwlqt false part 2
+    ○  kkmpptxzrspx false part 1
     ◆  zzzzzzzzzzzz true
     [EOF]
     ");
@@ -292,10 +292,10 @@ fn test_split_with_default_description() -> TestResult {
     let output = work_dir.run_jj(["split", "file1"]);
     insta::assert_snapshot!(output, @"
     ------- stderr -------
-    Selected changes : qpvuntsm ff633dcc TESTED=TODO
-    Remaining changes: rlvkpnrz b1d20b7e (no description set)
-    Working copy  (@) now at: rlvkpnrz b1d20b7e (no description set)
-    Parent commit (@-)      : qpvuntsm ff633dcc TESTED=TODO
+    Selected changes : rlvkpnrz 16dc7e13 TESTED=TODO
+    Remaining changes: qpvuntsm f40d53f2 (no description set)
+    Working copy  (@) now at: qpvuntsm f40d53f2 (no description set)
+    Parent commit (@-)      : rlvkpnrz 16dc7e13 TESTED=TODO
     [EOF]
     ");
 
@@ -310,7 +310,7 @@ fn test_split_with_default_description() -> TestResult {
 
     TESTED=TODO
 
-    JJ: Change ID: qpvuntsm
+    JJ: Change ID: rlvkpnrz
     JJ: This commit contains the following changes:
     JJ:     A file1
     JJ:
@@ -318,8 +318,8 @@ fn test_split_with_default_description() -> TestResult {
     "#);
     assert!(!test_env.env_root().join("editor2").exists());
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  rlvkpnrzqnoo false
-    ○  qpvuntsmwlqt false TESTED=TODO
+    @  qpvuntsmwlqt false
+    ○  rlvkpnrzqnoo false TESTED=TODO
     ◆  zzzzzzzzzzzz true
     [EOF]
     ");
@@ -367,20 +367,20 @@ fn test_split_with_descendants() -> TestResult {
         .join("\0"),
     )?;
     let output = work_dir.run_jj(["split", "file1", "-r", "qpvu"]);
-    insta::assert_snapshot!(output, @r"
+    insta::assert_snapshot!(output, @"
     ------- stderr -------
     Rebased 2 descendant commits.
-    Selected changes : qpvuntsm 74306e35 Add file1
-    Remaining changes: royxmykx 0a37745e Add file2
-    Working copy  (@) now at: kkmpptxz 7ee84812 Add file4
-    Parent commit (@-)      : rlvkpnrz d335bd94 Add file3
+    Selected changes : royxmykx e13e94b9 Add file1
+    Remaining changes: qpvuntsm cf8ebbab Add file2
+    Working copy  (@) now at: kkmpptxz 73a16519 Add file4
+    Parent commit (@-)      : rlvkpnrz ec4d3a14 Add file3
     [EOF]
     ");
     insta::assert_snapshot!(get_log_output(&work_dir), @"
     @  kkmpptxzrspx false Add file4
     ○  rlvkpnrzqnoo false Add file3
-    ○  royxmykxtrkr false Add file2
-    ○  qpvuntsmwlqt false Add file1
+    ○  qpvuntsmwlqt false Add file2
+    ○  royxmykxtrkr false Add file1
     ◆  zzzzzzzzzzzz true
     [EOF]
     ");
@@ -392,7 +392,7 @@ fn test_split_with_descendants() -> TestResult {
     JJ: Enter a description for the selected changes.
     Add file1 & file2
 
-    JJ: Change ID: qpvuntsm
+    JJ: Change ID: royxmykx
     JJ: This commit contains the following changes:
     JJ:     A file1
     JJ:
@@ -403,7 +403,7 @@ fn test_split_with_descendants() -> TestResult {
     JJ: Enter a description for the remaining changes.
     Add file1 & file2
 
-    JJ: Change ID: royxmykx
+    JJ: Change ID: qpvuntsm
     JJ: This commit contains the following changes:
     JJ:     A file2
     JJ:
@@ -415,11 +415,11 @@ fn test_split_with_descendants() -> TestResult {
     // - The rewritten commit from the snapshot after the files were added.
     // - The rewritten commit once the description is added during `jj commit`.
     // - The rewritten commit after the split.
-    let evolog_1 = work_dir.run_jj(["evolog", "-r", "qpvun"]);
+    let evolog_1 = work_dir.run_jj(["evolog", "-r", "royxm"]);
     insta::assert_snapshot!(evolog_1, @"
-    ○  qpvuntsm test.user@example.com 2001-02-03 08:05:12 74306e35
+    ○  royxmykx test.user@example.com 2001-02-03 08:05:12 e13e94b9
     │  Add file1
-    │  -- operation 8da478b86b17 split commit 1d2499e72cefc8a2b87ebb47569140857b96189f
+    │  -- operation 829427e5fee2 split commit 1d2499e72cefc8a2b87ebb47569140857b96189f
     ○  qpvuntsm/1 test.user@example.com 2001-02-03 08:05:08 1d2499e7 (hidden)
     │  Add file1 & file2
     │  -- operation 8f1bd50aa0bd commit f5700f8ef89e290e4e90ae6adc0908707e0d8c85
@@ -434,11 +434,11 @@ fn test_split_with_descendants() -> TestResult {
 
     // The evolog for the second commit is the same, except that the change id
     // changes after the split.
-    let evolog_2 = work_dir.run_jj(["evolog", "-r", "royxm"]);
+    let evolog_2 = work_dir.run_jj(["evolog", "-r", "qpvun"]);
     insta::assert_snapshot!(evolog_2, @"
-    ○  royxmykx test.user@example.com 2001-02-03 08:05:12 0a37745e
+    ○  qpvuntsm test.user@example.com 2001-02-03 08:05:12 cf8ebbab
     │  Add file2
-    │  -- operation 8da478b86b17 split commit 1d2499e72cefc8a2b87ebb47569140857b96189f
+    │  -- operation 829427e5fee2 split commit 1d2499e72cefc8a2b87ebb47569140857b96189f
     ○  qpvuntsm/1 test.user@example.com 2001-02-03 08:05:08 1d2499e7 (hidden)
     │  Add file1 & file2
     │  -- operation 8f1bd50aa0bd commit f5700f8ef89e290e4e90ae6adc0908707e0d8c85
@@ -484,21 +484,21 @@ fn test_split_with_merge_child() -> TestResult {
         ["write\nAdd file1", "next invocation\n", "write\nAdd file2"].join("\0"),
     )?;
     let output = work_dir.run_jj(["split", "-rsubject(a)", "file1"]);
-    insta::assert_snapshot!(output, @r"
+    insta::assert_snapshot!(output, @"
     ------- stderr -------
     Rebased 1 descendant commits.
-    Selected changes : kkmpptxz cc199567 Add file1
-    Remaining changes: royxmykx e488409f Add file2
-    Working copy  (@) now at: zsuskuln ace61421 (empty) 2
+    Selected changes : royxmykx ad21dad2 Add file1
+    Remaining changes: kkmpptxz 0922bd25 Add file2
+    Working copy  (@) now at: zsuskuln f59cd990 (empty) 2
     Parent commit (@-)      : qpvuntsm 884fe9b9 (empty) 1
-    Parent commit (@-)      : royxmykx e488409f Add file2
+    Parent commit (@-)      : kkmpptxz 0922bd25 Add file2
     [EOF]
     ");
     insta::assert_snapshot!(get_log_output(&work_dir), @"
     @    zsuskulnrvyr true 2
     ├─╮
-    │ ○  royxmykxtrkr false Add file2
-    │ ○  kkmpptxzrspx false Add file1
+    │ ○  kkmpptxzrspx false Add file2
+    │ ○  royxmykxtrkr false Add file1
     ○ │  qpvuntsmwlqt true 1
     ├─╯
     ◆  zzzzzzzzzzzz true
@@ -533,16 +533,16 @@ fn test_split_parallel_no_descendants() -> TestResult {
     let output = work_dir.run_jj(["split", "--parallel", "file1"]);
     insta::assert_snapshot!(output, @"
     ------- stderr -------
-    Selected changes : qpvuntsm 7bcd474c TESTED=TODO
-    Remaining changes: kkmpptxz 431886f6 (no description set)
-    Working copy  (@) now at: kkmpptxz 431886f6 (no description set)
+    Selected changes : kkmpptxz bd9b3db1 TESTED=TODO
+    Remaining changes: qpvuntsm 5597b805 (no description set)
+    Working copy  (@) now at: qpvuntsm 5597b805 (no description set)
     Parent commit (@-)      : zzzzzzzz 00000000 (empty) (no description set)
     Added 0 files, modified 0 files, removed 1 files
     [EOF]
     ");
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  kkmpptxzrspx false
-    │ ○  qpvuntsmwlqt false TESTED=TODO
+    @  qpvuntsmwlqt false
+    │ ○  kkmpptxzrspx false TESTED=TODO
     ├─╯
     ◆  zzzzzzzzzzzz true
     [EOF]
@@ -559,7 +559,7 @@ fn test_split_parallel_no_descendants() -> TestResult {
 
     TESTED=TODO
 
-    JJ: Change ID: qpvuntsm
+    JJ: Change ID: kkmpptxz
     JJ: This commit contains the following changes:
     JJ:     A file1
     JJ:
@@ -571,11 +571,11 @@ fn test_split_parallel_no_descendants() -> TestResult {
     // - The initial empty commit.
     // - The rewritten commit from the snapshot after the files were added.
     // - The rewritten commit after the split.
-    let evolog_1 = work_dir.run_jj(["evolog", "-r", "qpvun"]);
+    let evolog_1 = work_dir.run_jj(["evolog", "-r", "kkmpp"]);
     insta::assert_snapshot!(evolog_1, @"
-    ○  qpvuntsm test.user@example.com 2001-02-03 08:05:09 7bcd474c
+    ○  kkmpptxz test.user@example.com 2001-02-03 08:05:09 bd9b3db1
     │  TESTED=TODO
-    │  -- operation 46ec05e13358 split commit f5700f8ef89e290e4e90ae6adc0908707e0d8c85
+    │  -- operation 423d84e3ba48 split commit f5700f8ef89e290e4e90ae6adc0908707e0d8c85
     ○  qpvuntsm/1 test.user@example.com 2001-02-03 08:05:08 f5700f8e (hidden)
     │  (no description set)
     │  -- operation 9173705f4b2a snapshot working copy
@@ -587,11 +587,11 @@ fn test_split_parallel_no_descendants() -> TestResult {
 
     // The evolog for the second commit is the same, except that the change id
     // changes after the split.
-    let evolog_2 = work_dir.run_jj(["evolog", "-r", "kkmpp"]);
+    let evolog_2 = work_dir.run_jj(["evolog", "-r", "qpvun"]);
     insta::assert_snapshot!(evolog_2, @"
-    @  kkmpptxz test.user@example.com 2001-02-03 08:05:09 431886f6
+    @  qpvuntsm test.user@example.com 2001-02-03 08:05:09 5597b805
     │  (no description set)
-    │  -- operation 46ec05e13358 split commit f5700f8ef89e290e4e90ae6adc0908707e0d8c85
+    │  -- operation 423d84e3ba48 split commit f5700f8ef89e290e4e90ae6adc0908707e0d8c85
     ○  qpvuntsm/1 test.user@example.com 2001-02-03 08:05:08 f5700f8e (hidden)
     │  (no description set)
     │  -- operation 9173705f4b2a snapshot working copy
@@ -648,12 +648,12 @@ fn test_split_parallel_with_descendants() -> TestResult {
         .join("\0"),
     )?;
     let output = work_dir.run_jj(["split", "--parallel", "file1"]);
-    insta::assert_snapshot!(output, @r"
+    insta::assert_snapshot!(output, @"
     ------- stderr -------
     Rebased 2 descendant commits.
-    Selected changes : qpvuntsm 18c85f56 Add file1
-    Remaining changes: vruxwmqv cbdfd9cf Add file2
-    Working copy  (@) now at: vruxwmqv cbdfd9cf Add file2
+    Selected changes : vruxwmqv 3f0980cb Add file1
+    Remaining changes: qpvuntsm dff79d19 Add file2
+    Working copy  (@) now at: qpvuntsm dff79d19 Add file2
     Parent commit (@-)      : zzzzzzzz 00000000 (empty) (no description set)
     Added 0 files, modified 0 files, removed 1 files
     [EOF]
@@ -662,8 +662,8 @@ fn test_split_parallel_with_descendants() -> TestResult {
     ○  kkmpptxzrspx false Add file4
     ○    rlvkpnrzqnoo false Add file3
     ├─╮
-    │ @  vruxwmqvtpmx false Add file2
-    ○ │  qpvuntsmwlqt false Add file1
+    │ @  qpvuntsmwlqt false Add file2
+    ○ │  vruxwmqvtpmx false Add file1
     ├─╯
     ◆  zzzzzzzzzzzz true
     [EOF]
@@ -676,7 +676,7 @@ fn test_split_parallel_with_descendants() -> TestResult {
     JJ: Enter a description for the selected changes.
     Add file1 & file2
 
-    JJ: Change ID: qpvuntsm
+    JJ: Change ID: vruxwmqv
     JJ: This commit contains the following changes:
     JJ:     A file1
     JJ:
@@ -687,7 +687,7 @@ fn test_split_parallel_with_descendants() -> TestResult {
     JJ: Enter a description for the remaining changes.
     Add file1 & file2
 
-    JJ: Change ID: vruxwmqv
+    JJ: Change ID: qpvuntsm
     JJ: This commit contains the following changes:
     JJ:     A file2
     JJ:
@@ -727,22 +727,22 @@ fn test_split_parallel_with_merge_child() -> TestResult {
         ["write\nAdd file1", "next invocation\n", "write\nAdd file2"].join("\0"),
     )?;
     let output = work_dir.run_jj(["split", "-rsubject(a)", "--parallel", "file1"]);
-    insta::assert_snapshot!(output, @r"
+    insta::assert_snapshot!(output, @"
     ------- stderr -------
     Rebased 1 descendant commits.
-    Selected changes : kkmpptxz cc199567 Add file1
-    Remaining changes: royxmykx 82a5c527 Add file2
-    Working copy  (@) now at: zsuskuln b7cdcdec (empty) 2
+    Selected changes : royxmykx ad21dad2 Add file1
+    Remaining changes: kkmpptxz 23a2daac Add file2
+    Working copy  (@) now at: zsuskuln f1fcb7a6 (empty) 2
     Parent commit (@-)      : qpvuntsm 884fe9b9 (empty) 1
-    Parent commit (@-)      : kkmpptxz cc199567 Add file1
-    Parent commit (@-)      : royxmykx 82a5c527 Add file2
+    Parent commit (@-)      : royxmykx ad21dad2 Add file1
+    Parent commit (@-)      : kkmpptxz 23a2daac Add file2
     [EOF]
     ");
     insta::assert_snapshot!(get_log_output(&work_dir), @"
     @      zsuskulnrvyr true 2
     ├─┬─╮
-    │ │ ○  royxmykxtrkr false Add file2
-    │ ○ │  kkmpptxzrspx false Add file1
+    │ │ ○  kkmpptxzrspx false Add file2
+    │ ○ │  royxmykxtrkr false Add file1
     │ ├─╯
     ○ │  qpvuntsmwlqt true 1
     ├─╯
@@ -779,21 +779,21 @@ fn test_split_parallel_with_conflict() -> TestResult {
         ["write file\nline 1\nline 2.1\nline 3\n"].join("\0"),
     )?;
     let output = work_dir.run_jj(["split", "--parallel", "-i", "-m="]);
-    insta::assert_snapshot!(output, @r"
+    insta::assert_snapshot!(output, @"
     ------- stderr -------
     Rebased 1 descendant commits.
-    Selected changes : rlvkpnrz abe15fea (no description set)
-    Remaining changes: royxmykx 4bbc5826 (conflict) (no description set)
-    Working copy  (@) now at: royxmykx 4bbc5826 (conflict) (no description set)
+    Selected changes : royxmykx ddb7c909 (no description set)
+    Remaining changes: rlvkpnrz 3dfda33c (conflict) (no description set)
+    Working copy  (@) now at: rlvkpnrz 3dfda33c (conflict) (no description set)
     Parent commit (@-)      : qpvuntsm ee8e9376 (no description set)
     Added 0 files, modified 1 files, removed 0 files
     Warning: There are unresolved conflicts at these paths:
     file    2-sided conflict
     New conflicts appeared in 1 commits:
-      royxmykx 4bbc5826 (conflict) (no description set)
+      rlvkpnrz 3dfda33c (conflict) (no description set)
     Hint: To resolve the conflicts, start by creating a commit on top of
     the conflicted commit:
-      jj new royxmykx
+      jj new rlvkpnrz
     Then use `jj resolve`, or edit the conflict markers in the file directly.
     Once the conflicts are resolved, you can inspect the result with `jj diff`.
     Then run `jj squash` to move the resolution into the conflicted commit.
@@ -802,8 +802,8 @@ fn test_split_parallel_with_conflict() -> TestResult {
     insta::assert_snapshot!(get_log_output(&work_dir), @"
     ○    kkmpptxzrspx false
     ├─╮
-    │ @  royxmykxtrkr false
-    ○ │  rlvkpnrzqnoo false
+    │ @  rlvkpnrzqnoo false
+    ○ │  royxmykxtrkr false
     ├─╯
     ○  qpvuntsmwlqt false
     ◆  zzzzzzzzzzzz true
@@ -852,28 +852,28 @@ fn test_split_empty() -> TestResult {
     work_dir.run_jj(["describe", "--message", "abc"]).success();
 
     let output = work_dir.run_jj(["split"]);
-    insta::assert_snapshot!(output, @r"
+    insta::assert_snapshot!(output, @"
     ------- stderr -------
     Hint: Using default editor ':builtin'; run `jj config set --user ui.diff-editor :builtin` to disable this message.
     Warning: Empty diff - won't run diff editor.
     Warning: All changes have been selected, so the original revision will become empty.
-    Selected changes : qpvuntsm a8bcd860 (empty) abc
-    Remaining changes: kkmpptxz 304fb14c (empty) abc
-    Working copy  (@) now at: kkmpptxz 304fb14c (empty) abc
-    Parent commit (@-)      : qpvuntsm a8bcd860 (empty) abc
+    Selected changes : kkmpptxz e9628e7f (empty) abc
+    Remaining changes: qpvuntsm 6fe455ca (empty) abc
+    Working copy  (@) now at: qpvuntsm 6fe455ca (empty) abc
+    Parent commit (@-)      : kkmpptxz e9628e7f (empty) abc
     [EOF]
     ");
 
     // With path argument (user meant to pass revision)
     let output = work_dir.run_jj(["split", "@"]);
-    insta::assert_snapshot!(output, @r"
+    insta::assert_snapshot!(output, @"
     ------- stderr -------
     Warning: No matching entries for paths: @
     Warning: All changes have been selected, so the original revision will become empty.
-    Selected changes : kkmpptxz cd55fd14 (empty) abc
-    Remaining changes: zsuskuln 49a292cc (empty) abc
-    Working copy  (@) now at: zsuskuln 49a292cc (empty) abc
-    Parent commit (@-)      : kkmpptxz cd55fd14 (empty) abc
+    Selected changes : zsuskuln f8b45f6f (empty) abc
+    Remaining changes: qpvuntsm 62dbf613 (empty) abc
+    Working copy  (@) now at: qpvuntsm 62dbf613 (empty) abc
+    Parent commit (@-)      : zsuskuln f8b45f6f (empty) abc
     [EOF]
     ");
     Ok(())
@@ -919,10 +919,10 @@ fn test_split_interactive() -> TestResult {
     let output = work_dir.run_jj(["split"]);
     insta::assert_snapshot!(output, @"
     ------- stderr -------
-    Selected changes : qpvuntsm c664a51b (no description set)
-    Remaining changes: rlvkpnrz 7e5d65b1 (no description set)
-    Working copy  (@) now at: rlvkpnrz 7e5d65b1 (no description set)
-    Parent commit (@-)      : qpvuntsm c664a51b (no description set)
+    Selected changes : rlvkpnrz 1ff7a783 (no description set)
+    Remaining changes: qpvuntsm 429f292f (no description set)
+    Working copy  (@) now at: qpvuntsm 429f292f (no description set)
+    Parent commit (@-)      : rlvkpnrz 1ff7a783 (no description set)
     [EOF]
     ");
 
@@ -942,7 +942,7 @@ fn test_split_interactive() -> TestResult {
     JJ: Enter a description for the selected changes.
 
 
-    JJ: Change ID: qpvuntsm
+    JJ: Change ID: rlvkpnrz
     JJ: This commit contains the following changes:
     JJ:     A file1
     JJ:
@@ -951,10 +951,10 @@ fn test_split_interactive() -> TestResult {
 
     let output = work_dir.run_jj(["log", "--summary"]);
     insta::assert_snapshot!(output, @"
-    @  rlvkpnrz test.user@example.com 2001-02-03 08:05:08 7e5d65b1
+    @  qpvuntsm test.user@example.com 2001-02-03 08:05:08 429f292f
     │  (no description set)
     │  A file2
-    ○  qpvuntsm test.user@example.com 2001-02-03 08:05:08 c664a51b
+    ○  rlvkpnrz test.user@example.com 2001-02-03 08:05:08 1ff7a783
     │  (no description set)
     │  A file1
     ◆  zzzzzzzz root() 00000000
@@ -997,10 +997,10 @@ fn test_split_interactive_with_paths() -> TestResult {
     let output = work_dir.run_jj(["split", "-i", "file1", "file2"]);
     insta::assert_snapshot!(output, @"
     ------- stderr -------
-    Selected changes : rlvkpnrz cdc9960a (no description set)
-    Remaining changes: kkmpptxz 7255f070 (no description set)
-    Working copy  (@) now at: kkmpptxz 7255f070 (no description set)
-    Parent commit (@-)      : rlvkpnrz cdc9960a (no description set)
+    Selected changes : kkmpptxz 0a5bea34 (no description set)
+    Remaining changes: rlvkpnrz 7326e6fd (no description set)
+    Working copy  (@) now at: rlvkpnrz 7326e6fd (no description set)
+    Parent commit (@-)      : kkmpptxz 0a5bea34 (no description set)
     [EOF]
     ");
 
@@ -1009,7 +1009,7 @@ fn test_split_interactive_with_paths() -> TestResult {
     JJ: Enter a description for the selected changes.
 
 
-    JJ: Change ID: rlvkpnrz
+    JJ: Change ID: kkmpptxz
     JJ: This commit contains the following changes:
     JJ:     A file1
     JJ:
@@ -1018,11 +1018,11 @@ fn test_split_interactive_with_paths() -> TestResult {
 
     let output = work_dir.run_jj(["log", "--summary"]);
     insta::assert_snapshot!(output, @"
-    @  kkmpptxz test.user@example.com 2001-02-03 08:05:09 7255f070
+    @  rlvkpnrz test.user@example.com 2001-02-03 08:05:09 7326e6fd
     │  (no description set)
     │  M file2
     │  M file3
-    ○  rlvkpnrz test.user@example.com 2001-02-03 08:05:09 cdc9960a
+    ○  kkmpptxz test.user@example.com 2001-02-03 08:05:09 0a5bea34
     │  (no description set)
     │  A file1
     ○  qpvuntsm test.user@example.com 2001-02-03 08:05:08 ff687a2f
@@ -1077,8 +1077,8 @@ fn test_split_with_multiple_workspaces_same_working_copy() -> TestResult {
     main_dir.run_jj(["split", "file2"]).success();
     // The working copy for both workspaces will be the second split commit.
     insta::assert_snapshot!(get_workspace_log_output(&main_dir), @"
-    @  royxmykxtrkr default@ second@ second-commit
-    ○  qpvuntsmwlqt first-commit
+    @  qpvuntsmwlqt default@ second@ second-commit
+    ○  royxmykxtrkr first-commit
     ◆  zzzzzzzzzzzz
     [EOF]
     ");
@@ -1091,8 +1091,8 @@ fn test_split_with_multiple_workspaces_same_working_copy() -> TestResult {
     )?;
     main_dir.run_jj(["split", "file2", "--parallel"]).success();
     insta::assert_snapshot!(get_workspace_log_output(&main_dir), @"
-    @  yostqsxwqrlt default@ second@ second-commit
-    │ ○  qpvuntsmwlqt first-commit
+    @  qpvuntsmwlqt default@ second@ second-commit
+    │ ○  yostqsxwqrlt first-commit
     ├─╯
     ◆  zzzzzzzzzzzz
     [EOF]
@@ -1136,8 +1136,8 @@ fn test_split_with_multiple_workspaces_different_working_copy() -> TestResult {
     main_dir.run_jj(["split", "file2"]).success();
     // Only the working copy commit for the default workspace changes.
     insta::assert_snapshot!(get_workspace_log_output(&main_dir), @"
-    @  mzvwutvlkqwt default@ second-commit
-    ○  qpvuntsmwlqt first-commit
+    @  qpvuntsmwlqt default@ second-commit
+    ○  mzvwutvlkqwt first-commit
     │ ○  pmmvwywvzvvn second@
     ├─╯
     ◆  zzzzzzzzzzzz
@@ -1152,8 +1152,8 @@ fn test_split_with_multiple_workspaces_different_working_copy() -> TestResult {
     )?;
     main_dir.run_jj(["split", "file2", "--parallel"]).success();
     insta::assert_snapshot!(get_workspace_log_output(&main_dir), @"
-    @  vruxwmqvtpmx default@ second-commit
-    │ ○  qpvuntsmwlqt first-commit
+    @  qpvuntsmwlqt default@ second-commit
+    │ ○  vruxwmqvtpmx first-commit
     ├─╯
     │ ○  pmmvwywvzvvn second@
     ├─╯
@@ -1193,10 +1193,10 @@ fn test_split_with_non_empty_description_and_trailers() -> TestResult {
     let output = work_dir.run_jj(["split", "file1"]);
     insta::assert_snapshot!(output, @"
     ------- stderr -------
-    Selected changes : qpvuntsm c7f7b14b part 1
-    Remaining changes: kkmpptxz ac33a5a9 part 2
-    Working copy  (@) now at: kkmpptxz ac33a5a9 part 2
-    Parent commit (@-)      : qpvuntsm c7f7b14b part 1
+    Selected changes : kkmpptxz 530f78ed part 1
+    Remaining changes: qpvuntsm 88189e08 part 2
+    Working copy  (@) now at: qpvuntsm 88189e08 part 2
+    Parent commit (@-)      : kkmpptxz 530f78ed part 1
     [EOF]
     ");
 
@@ -1207,7 +1207,7 @@ fn test_split_with_non_empty_description_and_trailers() -> TestResult {
 
     Signed-off-by: test.user@example.com
 
-    JJ: Change ID: qpvuntsm
+    JJ: Change ID: kkmpptxz
     JJ: This commit contains the following changes:
     JJ:     A file1
     JJ:
@@ -1220,15 +1220,15 @@ fn test_split_with_non_empty_description_and_trailers() -> TestResult {
 
     Signed-off-by: test.user@example.com
 
-    JJ: Change ID: kkmpptxz
+    JJ: Change ID: qpvuntsm
     JJ: This commit contains the following changes:
     JJ:     A file2
     JJ:
     JJ: Lines starting with "JJ:" (like this one) will be removed.
     "#);
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  kkmpptxzrspx false part 2
-    ○  qpvuntsmwlqt false part 1
+    @  qpvuntsmwlqt false part 2
+    ○  kkmpptxzrspx false part 1
     ◆  zzzzzzzzzzzz true
     [EOF]
     ");
@@ -1249,16 +1249,16 @@ fn test_split_with_message() -> TestResult {
     let output = work_dir.run_jj(["split", "-m", "fix in file1", "file1"]);
     insta::assert_snapshot!(output, @"
     ------- stderr -------
-    Selected changes : qpvuntsm f2a70519 fix in file1
-    Remaining changes: kkmpptxz cac11766 my feature
-    Working copy  (@) now at: kkmpptxz cac11766 my feature
-    Parent commit (@-)      : qpvuntsm f2a70519 fix in file1
+    Selected changes : kkmpptxz b246503a fix in file1
+    Remaining changes: qpvuntsm e05b5012 my feature
+    Working copy  (@) now at: qpvuntsm e05b5012 my feature
+    Parent commit (@-)      : kkmpptxz b246503a fix in file1
     [EOF]
     ");
 
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  kkmpptxzrspx false my feature
-    ○  qpvuntsmwlqt false fix in file1
+    @  qpvuntsmwlqt false my feature
+    ○  kkmpptxzrspx false fix in file1
     ◆  zzzzzzzzzzzz true
     [EOF]
     ");
@@ -1275,16 +1275,16 @@ fn test_split_with_message() -> TestResult {
     ]);
     insta::assert_snapshot!(output, @"
     ------- stderr -------
-    Selected changes : qpvuntsm d01cf12d fix in file1
-    Remaining changes: royxmykx b1556ed9 my feature
-    Working copy  (@) now at: royxmykx b1556ed9 my feature
-    Parent commit (@-)      : qpvuntsm d01cf12d fix in file1
+    Selected changes : royxmykx 87fbb488 fix in file1
+    Remaining changes: qpvuntsm fb598346 my feature
+    Working copy  (@) now at: qpvuntsm fb598346 my feature
+    Parent commit (@-)      : royxmykx 87fbb488 fix in file1
     [EOF]
     ");
 
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  royxmykxtrkr false my feature
-    ○  qpvuntsmwlqt false fix in file1
+    @  qpvuntsmwlqt false my feature
+    ○  royxmykxtrkr false fix in file1
     │
     │  CC: test.user@example.com
     ◆  zzzzzzzzzzzz true
@@ -1569,16 +1569,6 @@ fn test_split_with_bookmarks(bookmark_behavior: BookmarkBehavior) -> TestResult
     test_env.run_jj_in(".", ["git", "init", "main"]).success();
     let main_dir = test_env.work_dir("main");
 
-    match bookmark_behavior {
-        BookmarkBehavior::LeaveBookmarkWithTarget => {
-            test_env.add_config("split.legacy-bookmark-behavior=false");
-        }
-        BookmarkBehavior::MoveBookmarkToChild => {
-            test_env.add_config("split.legacy-bookmark-behavior=true");
-        }
-        BookmarkBehavior::Default => (),
-    }
-
     // Setup.
     main_dir.run_jj(["desc", "-m", "first-commit"]).success();
     main_dir.write_file("file1", "foo");
@@ -1595,6 +1585,16 @@ fn test_split_with_bookmarks(bookmark_behavior: BookmarkBehavior) -> TestResult
     }
     let setup_opid = main_dir.current_operation_id();
 
+    match bookmark_behavior {
+        BookmarkBehavior::LeaveBookmarkWithTarget => {
+            test_env.add_config("split.legacy-bookmark-behavior=false");
+        }
+        BookmarkBehavior::MoveBookmarkToChild => {
+            test_env.add_config("split.legacy-bookmark-behavior=true");
+        }
+        BookmarkBehavior::Default => (),
+    }
+
     // Do the split.
     std::fs::write(
         &edit_script,
@@ -1604,39 +1604,67 @@ fn test_split_with_bookmarks(bookmark_behavior: BookmarkBehavior) -> TestResult
     match bookmark_behavior {
         BookmarkBehavior::LeaveBookmarkWithTarget => {
             insta::allow_duplicates! {
-            insta::assert_snapshot!(output, @"
+            insta::assert_snapshot!(output, @r#"
             ------- stderr -------
+            Warning: Deprecated user-level config: split.legacy-bookmark-behavior is updated to split.identity-strategy = ["selected"]
             Selected changes : qpvuntsm a481fe8a *le-signet* | first-commit
             Remaining changes: mzvwutvl 5f597a6e second-commit
             Working copy  (@) now at: mzvwutvl 5f597a6e second-commit
             Parent commit (@-)      : qpvuntsm a481fe8a *le-signet* | first-commit
             [EOF]
-            ");
+            "#);
             }
             insta::allow_duplicates! {
-            insta::assert_snapshot!(get_log_output(&main_dir), @"
+            insta::assert_snapshot!(get_log_output(&main_dir), @r#"
             @  mzvwutvlkqwt false second-commit
             ○  qpvuntsmwlqt false *le-signet* first-commit
             ◆  zzzzzzzzzzzz true
             [EOF]
-            ");
+            ------- stderr -------
+            Warning: Deprecated user-level config: split.legacy-bookmark-behavior is updated to split.identity-strategy = ["selected"]
+            [EOF]
+            "#);
+            }
+        }
+        BookmarkBehavior::MoveBookmarkToChild => {
+            insta::allow_duplicates! {
+            insta::assert_snapshot!(output, @r#"
+            ------- stderr -------
+            Warning: Deprecated user-level config: split.legacy-bookmark-behavior is updated to split.identity-strategy = ["remaining"]
+            Selected changes : mzvwutvl ac5cf500 first-commit
+            Remaining changes: qpvuntsm a13c536a *le-signet* | second-commit
+            Working copy  (@) now at: qpvuntsm a13c536a *le-signet* | second-commit
+            Parent commit (@-)      : mzvwutvl ac5cf500 first-commit
+            [EOF]
+            "#);
+            }
+            insta::allow_duplicates! {
+            insta::assert_snapshot!(get_log_output(&main_dir), @r#"
+            @  qpvuntsmwlqt false *le-signet* second-commit
+            ○  mzvwutvlkqwt false first-commit
+            ◆  zzzzzzzzzzzz true
+            [EOF]
+            ------- stderr -------
+            Warning: Deprecated user-level config: split.legacy-bookmark-behavior is updated to split.identity-strategy = ["remaining"]
+            [EOF]
+            "#);
             }
         }
-        BookmarkBehavior::Default | BookmarkBehavior::MoveBookmarkToChild => {
+        BookmarkBehavior::Default => {
             insta::allow_duplicates! {
             insta::assert_snapshot!(output, @"
             ------- stderr -------
-            Selected changes : qpvuntsm a481fe8a first-commit
-            Remaining changes: mzvwutvl 5f597a6e *le-signet* | second-commit
-            Working copy  (@) now at: mzvwutvl 5f597a6e *le-signet* | second-commit
-            Parent commit (@-)      : qpvuntsm a481fe8a first-commit
+            Selected changes : mzvwutvl ac5cf500 first-commit
+            Remaining changes: qpvuntsm a13c536a *le-signet* | second-commit
+            Working copy  (@) now at: qpvuntsm a13c536a *le-signet* | second-commit
+            Parent commit (@-)      : mzvwutvl ac5cf500 first-commit
             [EOF]
             ");
             }
             insta::allow_duplicates! {
             insta::assert_snapshot!(get_log_output(&main_dir), @"
-            @  mzvwutvlkqwt false *le-signet* second-commit
-            ○  qpvuntsmwlqt false first-commit
+            @  qpvuntsmwlqt false *le-signet* second-commit
+            ○  mzvwutvlkqwt false first-commit
             ◆  zzzzzzzzzzzz true
             [EOF]
             ");
@@ -1654,20 +1682,37 @@ fn test_split_with_bookmarks(bookmark_behavior: BookmarkBehavior) -> TestResult
     match bookmark_behavior {
         BookmarkBehavior::LeaveBookmarkWithTarget => {
             insta::allow_duplicates! {
-            insta::assert_snapshot!(get_log_output(&main_dir), @"
+            insta::assert_snapshot!(get_log_output(&main_dir), @r#"
             @  vruxwmqvtpmx false second-commit
             │ ○  qpvuntsmwlqt false *le-signet* first-commit
             ├─╯
             ◆  zzzzzzzzzzzz true
             [EOF]
-            ");
+            ------- stderr -------
+            Warning: Deprecated user-level config: split.legacy-bookmark-behavior is updated to split.identity-strategy = ["selected"]
+            [EOF]
+            "#);
             }
         }
-        BookmarkBehavior::Default | BookmarkBehavior::MoveBookmarkToChild => {
+        BookmarkBehavior::MoveBookmarkToChild => {
+            insta::allow_duplicates! {
+            insta::assert_snapshot!(get_log_output(&main_dir), @r#"
+            @  qpvuntsmwlqt false *le-signet* second-commit
+            │ ○  vruxwmqvtpmx false first-commit
+            ├─╯
+            ◆  zzzzzzzzzzzz true
+            [EOF]
+            ------- stderr -------
+            Warning: Deprecated user-level config: split.legacy-bookmark-behavior is updated to split.identity-strategy = ["remaining"]
+            [EOF]
+            "#);
+            }
+        }
+        BookmarkBehavior::Default => {
             insta::allow_duplicates! {
             insta::assert_snapshot!(get_log_output(&main_dir), @"
-            @  vruxwmqvtpmx false *le-signet* second-commit
-            │ ○  qpvuntsmwlqt false first-commit
+            @  qpvuntsmwlqt false *le-signet* second-commit
+            │ ○  vruxwmqvtpmx false first-commit
             ├─╯
             ◆  zzzzzzzzzzzz true
             [EOF]
@@ -1678,6 +1723,388 @@ fn test_split_with_bookmarks(bookmark_behavior: BookmarkBehavior) -> TestResult
     Ok(())
 }
 
+#[test]
+fn test_split_identity_strategy() -> TestResult {
+    let mut test_env = TestEnvironment::default();
+    let edit_script = test_env.set_up_fake_editor();
+    test_env.run_jj_in(".", ["git", "init", "main"]).success();
+    let main_dir = test_env.work_dir("main");
+
+    // Setup.
+    main_dir.run_jj(["desc", "-m", "first-commit"]).success();
+    main_dir.write_file("file1", "foo");
+    main_dir.write_file("file2", "foo");
+    main_dir
+        .run_jj(["bookmark", "set", "*le-signet*", "-r", "@"])
+        .success();
+
+    // 1. Test strategy ["selected"]: parent keeps Change ID and bookmark
+    test_env.add_config(r#"split.identity-strategy = ["selected"]"#);
+    std::fs::write(
+        &edit_script,
+        ["", "next invocation\n", "write\nsecond-commit"].join("\0"),
+    )?;
+    let output = main_dir.run_jj(["split", "file2"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : qpvuntsm 54c7e261 *le-signet* | first-commit
+    Remaining changes: zsuskuln 293f3d5b second-commit
+    Working copy  (@) now at: zsuskuln 293f3d5b second-commit
+    Parent commit (@-)      : qpvuntsm 54c7e261 *le-signet* | first-commit
+    [EOF]
+    ");
+    insta::assert_snapshot!(get_log_output(&main_dir), @"
+    @  zsuskulnrvyr false second-commit
+    ○  qpvuntsmwlqt false *le-signet* first-commit
+    ◆  zzzzzzzzzzzz true
+    [EOF]
+    ");
+
+    // 2. Test strategy ["remaining"]: child keeps Change ID and bookmark
+    main_dir.run_jj(["undo"]).success();
+    test_env.add_config(r#"split.identity-strategy = ["remaining"]"#);
+    std::fs::write(
+        &edit_script,
+        ["", "next invocation\n", "write\nsecond-commit"].join("\0"),
+    )?;
+    let output = main_dir.run_jj(["split", "file2"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : yqosqzyt 1bb7b7b4 first-commit
+    Remaining changes: qpvuntsm 71bd393c *le-signet* | second-commit
+    Working copy  (@) now at: qpvuntsm 71bd393c *le-signet* | second-commit
+    Parent commit (@-)      : yqosqzyt 1bb7b7b4 first-commit
+    [EOF]
+    ");
+    insta::assert_snapshot!(get_log_output(&main_dir), @"
+    @  qpvuntsmwlqt false *le-signet* second-commit
+    ○  yqosqzytrlsw false first-commit
+    ◆  zzzzzzzzzzzz true
+    [EOF]
+    ");
+
+    // 3. Test strategy ["selected"] with --parallel: selected keeps Change ID and
+    //    bookmark
+    main_dir.run_jj(["undo"]).success();
+    test_env.add_config(r#"split.identity-strategy = ["selected"]"#);
+    std::fs::write(
+        &edit_script,
+        ["", "next invocation\n", "write\nsecond-commit"].join("\0"),
+    )?;
+    let output = main_dir.run_jj(["split", "file2", "--parallel"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : qpvuntsm 192b9f8a *le-signet* | first-commit
+    Remaining changes: znkkpsqq bc5f19e1 second-commit
+    Working copy  (@) now at: znkkpsqq bc5f19e1 second-commit
+    Parent commit (@-)      : zzzzzzzz 00000000 (empty) (no description set)
+    Added 0 files, modified 0 files, removed 1 files
+    [EOF]
+    ");
+    insta::assert_snapshot!(get_log_output(&main_dir), @"
+    @  znkkpsqqskkl false second-commit
+    │ ○  qpvuntsmwlqt false *le-signet* first-commit
+    ├─╯
+    ◆  zzzzzzzzzzzz true
+    [EOF]
+    ");
+
+    // 4. Test strategy ["selected"] with move flags:
+    // The extracted/selected commit retains the original Change ID and bookmark at
+    // the new destination, while the origin commit receives a new Change ID.
+    main_dir.run_jj(["undo"]).success();
+    let output = main_dir.run_jj([
+        "--config=split.identity-strategy=[\"selected\"]",
+        "split",
+        "-m",
+        "extracted-commit",
+        "-r",
+        "qpvuntsmwlqt",
+        "--insert-after",
+        "qpvuntsmwlqt",
+        "file1",
+    ]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : qpvuntsm d3f4f708 *le-signet* | extracted-commit
+    Remaining changes: wqnwkozp 0de02004 first-commit
+    Working copy  (@) now at: qpvuntsm d3f4f708 *le-signet* | extracted-commit
+    Parent commit (@-)      : wqnwkozp 0de02004 first-commit
+    [EOF]
+    ");
+    insta::assert_snapshot!(get_log_output(&main_dir), @"
+    @  qpvuntsmwlqt false *le-signet* extracted-commit
+    ○  wqnwkozpkust false first-commit
+    ◆  zzzzzzzzzzzz true
+    [EOF]
+    ");
+
+    // 5. Test invalid strategy produces user error
+    main_dir.run_jj(["undo"]).success();
+    test_env.add_config(r#"split.identity-strategy = ["invalid-strategy"]"#);
+    let output = main_dir.run_jj(["split", "file2"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Error: Invalid identity strategy `invalid-strategy`.
+    [EOF]
+    [exit status: 1]
+    ");
+
+    Ok(())
+}
+
+#[test]
+fn test_split_follow_description() -> TestResult {
+    let mut test_env = TestEnvironment::default();
+    let edit_script = test_env.set_up_fake_editor();
+    test_env.run_jj_in(".", ["git", "init", "main"]).success();
+    let main_dir = test_env.work_dir("main");
+
+    // Configure fallback chain: follow-description then selected
+    test_env.add_config(r#"split.identity-strategy = ["follow-description", "selected"]"#);
+
+    // Setup commit with an original description
+    main_dir
+        .run_jj(["desc", "-m", "original PR title"])
+        .success();
+    main_dir.write_file("file1", "foo");
+    main_dir.write_file("file2", "foo");
+    main_dir
+        .run_jj(["bookmark", "set", "*le-signet*", "-r", "@"])
+        .success();
+
+    // Case 1: First commit keeps original description, second gets new description
+    // -> parent inherits original Change ID & bookmark
+    std::fs::write(
+        &edit_script,
+        [
+            "dump editor1",
+            "write\noriginal PR title",
+            "next invocation\n",
+            "dump editor2",
+            "write\nnew follow-up PR title",
+        ]
+        .join("\0"),
+    )?;
+    let output = main_dir.run_jj(["split", "file2"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : qpvuntsm 009211e0 *le-signet* | original PR title
+    Remaining changes: zsuskuln d9f6ae6c new follow-up PR title
+    Working copy  (@) now at: zsuskuln d9f6ae6c new follow-up PR title
+    Parent commit (@-)      : qpvuntsm 009211e0 *le-signet* | original PR title
+    [EOF]
+    ");
+    insta::assert_snapshot!(get_log_output(&main_dir), @"
+    @  zsuskulnrvyr false new follow-up PR title
+    ○  qpvuntsmwlqt false *le-signet* original PR title
+    ◆  zzzzzzzzzzzz true
+    [EOF]
+    ");
+
+    // Case 2: First commit gets new description, second retains original
+    // description -> child inherits original Change ID & bookmark
+    main_dir.run_jj(["undo"]).success();
+    std::fs::write(
+        &edit_script,
+        [
+            "dump editor1",
+            "write\nprerequisite refactoring",
+            "next invocation\n",
+            "dump editor2",
+            "write\noriginal PR title",
+        ]
+        .join("\0"),
+    )?;
+    let output = main_dir.run_jj(["split", "file2"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : spxsnpux 9f1a389b prerequisite refactoring
+    Remaining changes: qpvuntsm aa02719a *le-signet* | original PR title
+    Working copy  (@) now at: qpvuntsm aa02719a *le-signet* | original PR title
+    Parent commit (@-)      : spxsnpux 9f1a389b prerequisite refactoring
+    [EOF]
+    ");
+    insta::assert_snapshot!(get_log_output(&main_dir), @"
+    @  qpvuntsmwlqt false *le-signet* original PR title
+    ○  spxsnpuxtvxq false prerequisite refactoring
+    ◆  zzzzzzzzzzzz true
+    [EOF]
+    ");
+
+    // Case 3: Both descriptions modified -> yields to fallback strategy
+    // ("selected")
+    main_dir.run_jj(["undo"]).success();
+    std::fs::write(
+        &edit_script,
+        [
+            "dump editor1",
+            "write\nnew description 1",
+            "next invocation\n",
+            "dump editor2",
+            "write\nnew description 2",
+        ]
+        .join("\0"),
+    )?;
+    let output = main_dir.run_jj(["split", "file2"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : qpvuntsm 7ed1fe09 *le-signet* | new description 1
+    Remaining changes: znkkpsqq 46e99400 new description 2
+    Working copy  (@) now at: znkkpsqq 46e99400 new description 2
+    Parent commit (@-)      : qpvuntsm 7ed1fe09 *le-signet* | new description 1
+    [EOF]
+    ");
+
+    // Case 4: Both descriptions modified with fallback strategy ("remaining")
+    main_dir.run_jj(["undo"]).success();
+    test_env.add_config(r#"split.identity-strategy = ["follow-description", "remaining"]"#);
+    std::fs::write(
+        &edit_script,
+        [
+            "dump editor1",
+            "write\nnew description 1",
+            "next invocation\n",
+            "dump editor2",
+            "write\nnew description 2",
+        ]
+        .join("\0"),
+    )?;
+    let output = main_dir.run_jj(["split", "file2"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : kmkuslsw fe81e63e new description 1
+    Remaining changes: qpvuntsm 8f372cca *le-signet* | new description 2
+    Working copy  (@) now at: qpvuntsm 8f372cca *le-signet* | new description 2
+    Parent commit (@-)      : kmkuslsw fe81e63e new description 1
+    [EOF]
+    ");
+
+    // Case 5: Fallback strategy ("remaining"), first commit keeps original
+    // description -> parent inherits original Change ID & bookmark
+    main_dir.run_jj(["undo"]).success();
+    std::fs::write(
+        &edit_script,
+        [
+            "dump editor1",
+            "write\noriginal PR title",
+            "next invocation\n",
+            "dump editor2",
+            "write\nnew follow-up PR title",
+        ]
+        .join("\0"),
+    )?;
+    let output = main_dir.run_jj(["split", "file2"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : qpvuntsm d7b7ae18 *le-signet* | original PR title
+    Remaining changes: rsllmpnm 71d5b850 new follow-up PR title
+    Working copy  (@) now at: rsllmpnm 71d5b850 new follow-up PR title
+    Parent commit (@-)      : qpvuntsm d7b7ae18 *le-signet* | original PR title
+    [EOF]
+    ");
+    insta::assert_snapshot!(get_log_output(&main_dir), @"
+    @  rsllmpnmslon false new follow-up PR title
+    ○  qpvuntsmwlqt false *le-signet* original PR title
+    ◆  zzzzzzzzzzzz true
+    [EOF]
+    ");
+
+    // Case 6: Fallback strategy ("remaining"), second commit keeps original
+    // description -> child inherits original Change ID & bookmark
+    main_dir.run_jj(["undo"]).success();
+    std::fs::write(
+        &edit_script,
+        [
+            "dump editor1",
+            "write\nprerequisite refactoring",
+            "next invocation\n",
+            "dump editor2",
+            "write\noriginal PR title",
+        ]
+        .join("\0"),
+    )?;
+    let output = main_dir.run_jj(["split", "file2"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : uyznsvlq 8cfb0e0b prerequisite refactoring
+    Remaining changes: qpvuntsm 9a46886b *le-signet* | original PR title
+    Working copy  (@) now at: qpvuntsm 9a46886b *le-signet* | original PR title
+    Parent commit (@-)      : uyznsvlq 8cfb0e0b prerequisite refactoring
+    [EOF]
+    ");
+    insta::assert_snapshot!(get_log_output(&main_dir), @"
+    @  qpvuntsmwlqt false *le-signet* original PR title
+    ○  uyznsvlquzzm false prerequisite refactoring
+    ◆  zzzzzzzzzzzz true
+    [EOF]
+    ");
+
+    // Case 7: Ambiguous (both keep original description) -> yields to fallback
+    // strategy ("selected")
+    main_dir.run_jj(["undo"]).success();
+    test_env.add_config(r#"split.identity-strategy = ["follow-description", "selected"]"#);
+    std::fs::write(
+        &edit_script,
+        [
+            "dump editor1",
+            "write\noriginal PR title",
+            "next invocation\n",
+            "dump editor2",
+            "write\noriginal PR title",
+        ]
+        .join("\0"),
+    )?;
+    let output = main_dir.run_jj(["split", "file2"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : qpvuntsm 350968a9 *le-signet* | original PR title
+    Remaining changes: nmzmmopx 62369bb2 original PR title
+    Working copy  (@) now at: nmzmmopx 62369bb2 original PR title
+    Parent commit (@-)      : qpvuntsm 350968a9 *le-signet* | original PR title
+    [EOF]
+    ");
+    insta::assert_snapshot!(get_log_output(&main_dir), @"
+    @  nmzmmopxokps false original PR title
+    ○  qpvuntsmwlqt false *le-signet* original PR title
+    ◆  zzzzzzzzzzzz true
+    [EOF]
+    ");
+
+    // Case 8: Original commit has empty description -> yields to fallback strategy
+    // ("selected")
+    main_dir.run_jj(["undo"]).success();
+    main_dir.run_jj(["desc", "-m", ""]).success();
+    std::fs::write(
+        &edit_script,
+        [
+            "dump editor1",
+            "write\nfirst description",
+            "next invocation\n",
+            "dump editor2",
+            "write\nsecond description",
+        ]
+        .join("\0"),
+    )?;
+    let output = main_dir.run_jj(["split", "file2"]);
+    insta::assert_snapshot!(output, @"
+    ------- stderr -------
+    Selected changes : qpvuntsm 76cf14b2 *le-signet* | first description
+    Remaining changes: pzsxstzt 6da41ff8 (no description set)
+    Working copy  (@) now at: pzsxstzt 6da41ff8 (no description set)
+    Parent commit (@-)      : qpvuntsm 76cf14b2 *le-signet* | first description
+    [EOF]
+    ");
+    insta::assert_snapshot!(get_log_output(&main_dir), @"
+    @  pzsxstztnpkv false
+    ○  qpvuntsmwlqt false *le-signet* first description
+    ◆  zzzzzzzzzzzz true
+    [EOF]
+    ");
+
+    Ok(())
+}
+
 #[test]
 fn test_split_with_editor_and_message_args() -> TestResult {
     let mut test_env = TestEnvironment::default();
@@ -1718,7 +2145,7 @@ fn test_split_with_editor_and_message_args() -> TestResult {
     JJ: Enter a description for the selected changes.
     message from command line
 
-    JJ: Change ID: qpvuntsm
+    JJ: Change ID: kkmpptxz
     JJ: This commit contains the following changes:
     JJ:     A file1
     JJ:
@@ -1731,15 +2158,15 @@ fn test_split_with_editor_and_message_args() -> TestResult {
     JJ: Enter a description for the remaining changes.
     original description
 
-    JJ: Change ID: kkmpptxz
+    JJ: Change ID: qpvuntsm
     JJ: This commit contains the following changes:
     JJ:     A file2
     JJ:
     JJ: Lines starting with "JJ:" (like this one) will be removed.
     "#);
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  kkmpptxzrspx false edited message 2
-    ○  qpvuntsmwlqt false edited message 1
+    @  qpvuntsmwlqt false edited message 2
+    ○  kkmpptxzrspx false edited message 1
     ◆  zzzzzzzzzzzz true
     [EOF]
     ");
@@ -1793,7 +2220,7 @@ fn test_split_with_editor_and_empty_message() -> TestResult {
 
     Trailer: value
 
-    JJ: Change ID: qpvuntsm
+    JJ: Change ID: kkmpptxz
     JJ: This commit contains the following changes:
     JJ:     A file1
     JJ:
@@ -1807,15 +2234,15 @@ fn test_split_with_editor_and_empty_message() -> TestResult {
 
     Trailer: value
 
-    JJ: Change ID: kkmpptxz
+    JJ: Change ID: qpvuntsm
     JJ: This commit contains the following changes:
     JJ:     A file2
     JJ:
     JJ: Lines starting with "JJ:" (like this one) will be removed.
     "#);
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  kkmpptxzrspx false second commit
-    ○  qpvuntsmwlqt false first commit
+    @  qpvuntsmwlqt false second commit
+    ○  kkmpptxzrspx false first commit
     ◆  zzzzzzzzzzzz true
     [EOF]
     ");
@@ -1855,7 +2282,7 @@ fn test_split_with_editor_without_message() -> TestResult {
     JJ: Enter a description for the selected changes.
     original description
 
-    JJ: Change ID: qpvuntsm
+    JJ: Change ID: kkmpptxz
     JJ: This commit contains the following changes:
     JJ:     A file1
     JJ:
@@ -1867,15 +2294,15 @@ fn test_split_with_editor_without_message() -> TestResult {
     JJ: Enter a description for the remaining changes.
     original description
 
-    JJ: Change ID: kkmpptxz
+    JJ: Change ID: qpvuntsm
     JJ: This commit contains the following changes:
     JJ:     A file2
     JJ:
     JJ: Lines starting with "JJ:" (like this one) will be removed.
     "#);
     insta::assert_snapshot!(get_log_output(&work_dir), @"
-    @  kkmpptxzrspx false from editor2
-    ○  qpvuntsmwlqt false from editor1
+    @  qpvuntsmwlqt false from editor2
+    ○  kkmpptxzrspx false from editor1
     ◆  zzzzzzzzzzzz true
     [EOF]
     ");
diff --git a/docs/config.md b/docs/config.md
index 8f2f9d53e88..e880a68b05d 100644
--- a/docs/config.md
+++ b/docs/config.md
@@ -1396,6 +1396,35 @@ The conflict marker style can also be customized per tool using the
 `merge-tools.TOOL.conflict-marker-style` option, which takes the same values as
 [`ui.conflict-marker-style`](#conflict-marker-style).
 
+## Splitting commits
+
+The `split.identity-strategy` setting configures the strategy chain that
+determines which of the two revisions resulting from `jj split` inherits the
+original change ID and any existing bookmarks.
+
+```toml
+[split]
+# First attempt to keep the change ID and bookmarks with the revision that keeps
+# the original description, then fall back to the revision with remaining changes:
+identity-strategy = ["follow-description", "remaining"]
+```
+
+The strategies defined in the config array are evaluated in order, falling back
+to the next one if it is unable to select an identity revision. The available
+strategies are:
+
+* `selected`: The revision containing the selected changes inherits the
+  original change ID and any existing bookmarks. The revision with the remaining
+  changes gets a new change ID.
+* `remaining` (default): The revision containing the remaining changes inherits the
+  original change ID and any existing bookmarks. The revision with the selected
+  changes gets a new change ID.
+* `follow-description`: Compares the descriptions of the two split revisions
+  with the original revision's description. If exactly one of the split revisions
+  retains the non-empty original description, that revision inherits the change
+  ID and bookmarks. If both were modified, both match, or the original
+  description was empty, this strategy yields to the next strategy in the chain.
+
 ## Code formatting and other file content transformations
 
 The `jj fix` command allows you to efficiently rewrite files in complex commit