diff --git a/crates/collab/src/tests/integration_tests.rs b/crates/collab/src/tests/integration_tests.rs
index 7d6199b109..bdf43124d4 100644
--- a/crates/collab/src/tests/integration_tests.rs
+++ b/crates/collab/src/tests/integration_tests.rs
@@ -3222,14 +3222,18 @@ async fn test_canceling_buffer_opening(
         .unwrap();
 
     // Open a buffer as client B but cancel after a random amount of time.
-    let buffer_b = project_b.update(cx_b, |p, cx| p.open_buffer_by_id(buffer_a.id() as u64, cx));
+    let buffer_b = project_b.update(cx_b, |p, cx| {
+        p.open_buffer_by_id(buffer_a.read_with(cx_a, |a, _| a.remote_id()), cx)
+    });
     deterministic.simulate_random_delay().await;
     drop(buffer_b);
 
     // Try opening the same buffer again as client B, and ensure we can
     // still do it despite the cancellation above.
     let buffer_b = project_b
-        .update(cx_b, |p, cx| p.open_buffer_by_id(buffer_a.id() as u64, cx))
+        .update(cx_b, |p, cx| {
+            p.open_buffer_by_id(buffer_a.read_with(cx_a, |a, _| a.remote_id()), cx)
+        })
         .await
         .unwrap();
     buffer_b.read_with(cx_b, |buf, _| assert_eq!(buf.text(), "abc"));
diff --git a/crates/copilot/src/copilot.rs b/crates/copilot/src/copilot.rs
index ea25355065..e51cad8e50 100644
--- a/crates/copilot/src/copilot.rs
+++ b/crates/copilot/src/copilot.rs
@@ -126,7 +126,7 @@ impl CopilotServer {
 struct RunningCopilotServer {
     lsp: Arc<LanguageServer>,
     sign_in_status: SignInStatus,
-    registered_buffers: HashMap<usize, RegisteredBuffer>,
+    registered_buffers: HashMap<u64, RegisteredBuffer>,
 }
 
 #[derive(Clone, Debug)]
@@ -162,7 +162,7 @@ impl Status {
 }
 
 struct RegisteredBuffer {
-    id: usize,
+    id: u64,
     uri: lsp::Url,
     language_id: String,
     snapshot: BufferSnapshot,
@@ -267,7 +267,7 @@ pub struct Copilot {
     http: Arc<dyn HttpClient>,
     node_runtime: Arc<NodeRuntime>,
     server: CopilotServer,
-    buffers: HashMap<usize, WeakModelHandle<Buffer>>,
+    buffers: HashMap<u64, WeakModelHandle<Buffer>>,
 }
 
 impl Entity for Copilot {
@@ -582,7 +582,7 @@ impl Copilot {
     }
 
     pub fn register_buffer(&mut self, buffer: &ModelHandle<Buffer>, cx: &mut ModelContext<Self>) {
-        let buffer_id = buffer.id();
+        let buffer_id = buffer.read(cx).remote_id();
         self.buffers.insert(buffer_id, buffer.downgrade());
 
         if let CopilotServer::Running(RunningCopilotServer {
@@ -596,7 +596,8 @@ impl Copilot {
                 return;
             }
 
-            registered_buffers.entry(buffer.id()).or_insert_with(|| {
+            let buffer_id = buffer.read(cx).remote_id();
+            registered_buffers.entry(buffer_id).or_insert_with(|| {
                 let uri: lsp::Url = uri_for_buffer(buffer, cx);
                 let language_id = id_for_language(buffer.read(cx).language());
                 let snapshot = buffer.read(cx).snapshot();
@@ -641,7 +642,8 @@ impl Copilot {
         cx: &mut ModelContext<Self>,
     ) -> Result<()> {
         if let Ok(server) = self.server.as_running() {
-            if let Some(registered_buffer) = server.registered_buffers.get_mut(&buffer.id()) {
+            let buffer_id = buffer.read(cx).remote_id();
+            if let Some(registered_buffer) = server.registered_buffers.get_mut(&buffer_id) {
                 match event {
                     language::Event::Edited => {
                         let _ = registered_buffer.report_changes(&buffer, cx);
@@ -695,7 +697,7 @@ impl Copilot {
         Ok(())
     }
 
-    fn unregister_buffer(&mut self, buffer_id: usize) {
+    fn unregister_buffer(&mut self, buffer_id: u64) {
         if let Ok(server) = self.server.as_running() {
             if let Some(buffer) = server.registered_buffers.remove(&buffer_id) {
                 server
@@ -800,7 +802,8 @@ impl Copilot {
             Err(error) => return Task::ready(Err(error)),
         };
         let lsp = server.lsp.clone();
-        let registered_buffer = server.registered_buffers.get_mut(&buffer.id()).unwrap();
+        let buffer_id = buffer.read(cx).remote_id();
+        let registered_buffer = server.registered_buffers.get_mut(&buffer_id).unwrap();
         let snapshot = registered_buffer.report_changes(buffer, cx);
         let buffer = buffer.read(cx);
         let uri = registered_buffer.uri.clone();
@@ -919,7 +922,9 @@ fn uri_for_buffer(buffer: &ModelHandle<Buffer>, cx: &AppContext) -> lsp::Url {
     if let Some(file) = buffer.read(cx).file().and_then(|file| file.as_local()) {
         lsp::Url::from_file_path(file.abs_path(cx)).unwrap()
     } else {
-        format!("buffer://{}", buffer.id()).parse().unwrap()
+        format!("buffer://{}", buffer.read(cx).remote_id())
+            .parse()
+            .unwrap()
     }
 }
 
diff --git a/crates/editor/src/editor.rs b/crates/editor/src/editor.rs
index 8771387cb7..5568ed79b5 100644
--- a/crates/editor/src/editor.rs
+++ b/crates/editor/src/editor.rs
@@ -2594,7 +2594,7 @@ impl Editor {
         let old_text = buffer.text_for_range(old_range.clone()).collect::<String>();
 
         let newest_selection = self.selections.newest_anchor();
-        if newest_selection.start.buffer_id != Some(buffer_handle.id()) {
+        if newest_selection.start.buffer_id != Some(buffer_handle.read(cx).remote_id()) {
             return None;
         }
 
@@ -2802,7 +2802,7 @@ impl Editor {
                     ),
                 );
             }
-            multibuffer.push_transaction(entries.iter().map(|(b, t)| (b, t)));
+            multibuffer.push_transaction(entries.iter().map(|(b, t)| (b, t)), cx);
             multibuffer
         });
 
@@ -5764,7 +5764,7 @@ impl Editor {
         cx: &mut ViewContext<Workspace>,
     ) {
         // If there are multiple definitions, open them in a multibuffer
-        locations.sort_by_key(|location| location.buffer.id());
+        locations.sort_by_key(|location| location.buffer.read(cx).remote_id());
         let mut locations = locations.into_iter().peekable();
         let mut ranges_to_highlight = Vec::new();
 
@@ -6059,7 +6059,7 @@ impl Editor {
             buffer.update(&mut cx, |buffer, cx| {
                 if let Some(transaction) = transaction {
                     if !buffer.is_singleton() {
-                        buffer.push_transaction(&transaction.0);
+                        buffer.push_transaction(&transaction.0, cx);
                     }
                 }
 
diff --git a/crates/editor/src/items.rs b/crates/editor/src/items.rs
index dcd49607fb..df93326e9a 100644
--- a/crates/editor/src/items.rs
+++ b/crates/editor/src/items.rs
@@ -704,10 +704,10 @@ impl Item for Editor {
             this.update(&mut cx, |editor, cx| {
                 editor.request_autoscroll(Autoscroll::fit(), cx)
             })?;
-            buffer.update(&mut cx, |buffer, _| {
+            buffer.update(&mut cx, |buffer, cx| {
                 if let Some(transaction) = transaction {
                     if !buffer.is_singleton() {
-                        buffer.push_transaction(&transaction.0);
+                        buffer.push_transaction(&transaction.0, cx);
                     }
                 }
             });
diff --git a/crates/editor/src/multi_buffer.rs b/crates/editor/src/multi_buffer.rs
index 39e66d0f93..a2160b47e5 100644
--- a/crates/editor/src/multi_buffer.rs
+++ b/crates/editor/src/multi_buffer.rs
@@ -43,7 +43,7 @@ pub struct ExcerptId(usize);
 
 pub struct MultiBuffer {
     snapshot: RefCell<MultiBufferSnapshot>,
-    buffers: RefCell<HashMap<usize, BufferState>>,
+    buffers: RefCell<HashMap<u64, BufferState>>,
     next_excerpt_id: usize,
     subscriptions: Topic,
     singleton: bool,
@@ -85,7 +85,7 @@ struct History {
 #[derive(Clone)]
 struct Transaction {
     id: TransactionId,
-    buffer_transactions: HashMap<usize, text::TransactionId>,
+    buffer_transactions: HashMap<u64, text::TransactionId>,
     first_edit_at: Instant,
     last_edit_at: Instant,
     suppress_grouping: bool,
@@ -145,7 +145,7 @@ pub struct ExcerptBoundary {
 struct Excerpt {
     id: ExcerptId,
     locator: Locator,
-    buffer_id: usize,
+    buffer_id: u64,
     buffer: BufferSnapshot,
     range: ExcerptRange<text::Anchor>,
     max_buffer_row: u32,
@@ -337,7 +337,7 @@ impl MultiBuffer {
         offset: T,
         theme: Option<&SyntaxTheme>,
         cx: &AppContext,
-    ) -> Option<(usize, Vec<OutlineItem<Anchor>>)> {
+    ) -> Option<(u64, Vec<OutlineItem<Anchor>>)> {
         self.read(cx).symbols_containing(offset, theme)
     }
 
@@ -394,7 +394,7 @@ impl MultiBuffer {
             is_insertion: bool,
             original_indent_column: u32,
         }
-        let mut buffer_edits: HashMap<usize, Vec<BufferEdit>> = Default::default();
+        let mut buffer_edits: HashMap<u64, Vec<BufferEdit>> = Default::default();
         let mut cursor = snapshot.excerpts.cursor::<usize>();
         for (ix, (range, new_text)) in edits.enumerate() {
             let new_text: Arc<str> = new_text.into();
@@ -593,7 +593,7 @@ impl MultiBuffer {
             if let Some(transaction_id) =
                 buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
             {
-                buffer_transactions.insert(buffer.id(), transaction_id);
+                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
             }
         }
 
@@ -614,12 +614,12 @@ impl MultiBuffer {
         }
     }
 
-    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T)
+    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &mut ModelContext<Self>)
     where
         T: IntoIterator<Item = (&'a ModelHandle<Buffer>, &'a language::Transaction)>,
     {
         self.history
-            .push_transaction(buffer_transactions, Instant::now());
+            .push_transaction(buffer_transactions, Instant::now(), cx);
         self.history.finalize_last_transaction();
     }
 
@@ -644,7 +644,7 @@ impl MultiBuffer {
         cursor_shape: CursorShape,
         cx: &mut ModelContext<Self>,
     ) {
-        let mut selections_by_buffer: HashMap<usize, Vec<Selection<text::Anchor>>> =
+        let mut selections_by_buffer: HashMap<u64, Vec<Selection<text::Anchor>>> =
             Default::default();
         let snapshot = self.read(cx);
         let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>();
@@ -785,8 +785,8 @@ impl MultiBuffer {
         let (mut tx, rx) = mpsc::channel(256);
         let task = cx.spawn(|this, mut cx| async move {
             for (buffer, ranges) in excerpts {
-                let buffer_id = buffer.id();
-                let buffer_snapshot = buffer.read_with(&cx, |buffer, _| buffer.snapshot());
+                let (buffer_id, buffer_snapshot) =
+                    buffer.read_with(&cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
 
                 let mut excerpt_ranges = Vec::new();
                 let mut range_counts = Vec::new();
@@ -855,7 +855,7 @@ impl MultiBuffer {
     where
         O: text::ToPoint + text::ToOffset,
     {
-        let buffer_id = buffer.id();
+        let buffer_id = buffer.read(cx).remote_id();
         let buffer_snapshot = buffer.read(cx).snapshot();
         let (excerpt_ranges, range_counts) =
             build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
@@ -924,7 +924,7 @@ impl MultiBuffer {
 
         self.sync(cx);
 
-        let buffer_id = buffer.id();
+        let buffer_id = buffer.read(cx).remote_id();
         let buffer_snapshot = buffer.read(cx).snapshot();
 
         let mut buffers = self.buffers.borrow_mut();
@@ -1051,7 +1051,7 @@ impl MultiBuffer {
         let buffers = self.buffers.borrow();
         let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>();
         for locator in buffers
-            .get(&buffer.id())
+            .get(&buffer.read(cx).remote_id())
             .map(|state| &state.excerpts)
             .into_iter()
             .flatten()
@@ -1321,7 +1321,7 @@ impl MultiBuffer {
             .collect()
     }
 
-    pub fn buffer(&self, buffer_id: usize) -> Option<ModelHandle<Buffer>> {
+    pub fn buffer(&self, buffer_id: u64) -> Option<ModelHandle<Buffer>> {
         self.buffers
             .borrow()
             .get(&buffer_id)
@@ -1478,8 +1478,8 @@ impl MultiBuffer {
         for (locator, buffer, buffer_edited) in excerpts_to_edit {
             new_excerpts.push_tree(cursor.slice(&Some(locator), Bias::Left, &()), &());
             let old_excerpt = cursor.item().unwrap();
-            let buffer_id = buffer.id();
             let buffer = buffer.read(cx);
+            let buffer_id = buffer.remote_id();
 
             let mut new_excerpt;
             if buffer_edited {
@@ -1605,11 +1605,11 @@ impl MultiBuffer {
                 let buffer_handle = if rng.gen() || self.buffers.borrow().is_empty() {
                     let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
                     buffers.push(cx.add_model(|cx| Buffer::new(0, text, cx)));
-                    let buffer = buffers.last().unwrap();
+                    let buffer = buffers.last().unwrap().read(cx);
                     log::info!(
                         "Creating new buffer {} with text: {:?}",
-                        buffer.id(),
-                        buffer.read(cx).text()
+                        buffer.remote_id(),
+                        buffer.text()
                     );
                     buffers.last().unwrap().clone()
                 } else {
@@ -1637,7 +1637,7 @@ impl MultiBuffer {
                     .collect::<Vec<_>>();
                 log::info!(
                     "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
-                    buffer_handle.id(),
+                    buffer_handle.read(cx).remote_id(),
                     ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
                     ranges
                         .iter()
@@ -1830,7 +1830,7 @@ impl MultiBufferSnapshot {
         (start..end, word_kind)
     }
 
-    pub fn as_singleton(&self) -> Option<(&ExcerptId, usize, &BufferSnapshot)> {
+    pub fn as_singleton(&self) -> Option<(&ExcerptId, u64, &BufferSnapshot)> {
         if self.singleton {
             self.excerpts
                 .iter()
@@ -2938,7 +2938,7 @@ impl MultiBufferSnapshot {
         &self,
         offset: T,
         theme: Option<&SyntaxTheme>,
-    ) -> Option<(usize, Vec<OutlineItem<Anchor>>)> {
+    ) -> Option<(u64, Vec<OutlineItem<Anchor>>)> {
         let anchor = self.anchor_before(offset);
         let excerpt_id = anchor.excerpt_id();
         let excerpt = self.excerpt(excerpt_id)?;
@@ -2978,7 +2978,7 @@ impl MultiBufferSnapshot {
         }
     }
 
-    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<usize> {
+    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<u64> {
         Some(self.excerpt(excerpt_id)?.buffer_id)
     }
 
@@ -3116,7 +3116,7 @@ impl History {
     fn end_transaction(
         &mut self,
         now: Instant,
-        buffer_transactions: HashMap<usize, TransactionId>,
+        buffer_transactions: HashMap<u64, TransactionId>,
     ) -> bool {
         assert_ne!(self.transaction_depth, 0);
         self.transaction_depth -= 1;
@@ -3141,8 +3141,12 @@ impl History {
         }
     }
 
-    fn push_transaction<'a, T>(&mut self, buffer_transactions: T, now: Instant)
-    where
+    fn push_transaction<'a, T>(
+        &mut self,
+        buffer_transactions: T,
+        now: Instant,
+        cx: &mut ModelContext<MultiBuffer>,
+    ) where
         T: IntoIterator<Item = (&'a ModelHandle<Buffer>, &'a language::Transaction)>,
     {
         assert_eq!(self.transaction_depth, 0);
@@ -3150,7 +3154,7 @@ impl History {
             id: self.next_transaction_id.tick(),
             buffer_transactions: buffer_transactions
                 .into_iter()
-                .map(|(buffer, transaction)| (buffer.id(), transaction.id))
+                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
                 .collect(),
             first_edit_at: now,
             last_edit_at: now,
@@ -3247,7 +3251,7 @@ impl Excerpt {
     fn new(
         id: ExcerptId,
         locator: Locator,
-        buffer_id: usize,
+        buffer_id: u64,
         buffer: BufferSnapshot,
         range: ExcerptRange<text::Anchor>,
         has_trailing_newline: bool,
@@ -4715,7 +4719,7 @@ mod tests {
                         "Inserting excerpt at {} of {} for buffer {}: {:?}[{:?}] = {:?}",
                         excerpt_ix,
                         expected_excerpts.len(),
-                        buffer_handle.id(),
+                        buffer_handle.read(cx).remote_id(),
                         buffer.text(),
                         start_ix..end_ix,
                         &buffer.text()[start_ix..end_ix]
@@ -4801,8 +4805,8 @@ mod tests {
 
             let mut excerpt_starts = excerpt_starts.into_iter();
             for (buffer, range) in &expected_excerpts {
-                let buffer_id = buffer.id();
                 let buffer = buffer.read(cx);
+                let buffer_id = buffer.remote_id();
                 let buffer_range = range.to_offset(buffer);
                 let buffer_start_point = buffer.offset_to_point(buffer_range.start);
                 let buffer_start_point_utf16 =
diff --git a/crates/editor/src/multi_buffer/anchor.rs b/crates/editor/src/multi_buffer/anchor.rs
index 4ecab76c48..9a5145c244 100644
--- a/crates/editor/src/multi_buffer/anchor.rs
+++ b/crates/editor/src/multi_buffer/anchor.rs
@@ -8,7 +8,7 @@ use sum_tree::Bias;
 
 #[derive(Clone, Copy, Eq, PartialEq, Debug, Hash)]
 pub struct Anchor {
-    pub(crate) buffer_id: Option<usize>,
+    pub(crate) buffer_id: Option<u64>,
     pub(crate) excerpt_id: ExcerptId,
     pub(crate) text_anchor: text::Anchor,
 }
diff --git a/crates/project/src/project.rs b/crates/project/src/project.rs
index 2b731099ed..40687ce0a7 100644
--- a/crates/project/src/project.rs
+++ b/crates/project/src/project.rs
@@ -125,7 +125,7 @@ pub struct Project {
     /// Used for re-issuing buffer requests when peers temporarily disconnect
     incomplete_remote_buffers: HashMap<u64, Option<ModelHandle<Buffer>>>,
     buffer_snapshots: HashMap<u64, HashMap<LanguageServerId, Vec<LspBufferSnapshot>>>, // buffer_id -> server_id -> vec of snapshots
-    buffers_being_formatted: HashSet<usize>,
+    buffers_being_formatted: HashSet<u64>,
     nonce: u128,
     _maintain_buffer_languages: Task<()>,
     _maintain_workspace_config: Task<()>,
@@ -3204,9 +3204,11 @@ impl Project {
             cx.spawn(|this, mut cx| async move {
                 // Do not allow multiple concurrent formatting requests for the
                 // same buffer.
-                this.update(&mut cx, |this, _| {
-                    buffers_with_paths_and_servers
-                        .retain(|(buffer, _, _)| this.buffers_being_formatted.insert(buffer.id()));
+                this.update(&mut cx, |this, cx| {
+                    buffers_with_paths_and_servers.retain(|(buffer, _, _)| {
+                        this.buffers_being_formatted
+                            .insert(buffer.read(cx).remote_id())
+                    });
                 });
 
                 let _cleanup = defer({
@@ -3214,9 +3216,10 @@ impl Project {
                     let mut cx = cx.clone();
                     let buffers = &buffers_with_paths_and_servers;
                     move || {
-                        this.update(&mut cx, |this, _| {
+                        this.update(&mut cx, |this, cx| {
                             for (buffer, _, _) in buffers {
-                                this.buffers_being_formatted.remove(&buffer.id());
+                                this.buffers_being_formatted
+                                    .remove(&buffer.read(cx).remote_id());
                             }
                         });
                     }
diff --git a/crates/workspace/src/item.rs b/crates/workspace/src/item.rs
index 38e6b92b34..43c4544611 100644
--- a/crates/workspace/src/item.rs
+++ b/crates/workspace/src/item.rs
@@ -60,7 +60,7 @@ pub trait Item: View {
         style: &theme::Tab,
         cx: &AppContext,
     ) -> AnyElement<V>;
-    fn for_each_project_item(&self, _: &AppContext, _: &mut dyn FnMut(usize, &dyn project::Item)) {}
+    fn for_each_project_item(&self, _: &AppContext, _: &mut dyn FnMut(usize, &dyn project::Item)) {} // (model id, Item)
     fn is_singleton(&self, _cx: &AppContext) -> bool {
         false
     }