Improve claude tools (#36538)

- Return unified diff from `Edit` tool so model can see the final state
- Format on save if enabled
- Provide `Write` tool
- Disable `MultiEdit` tool
- Better prompting

Release Notes:

- N/A

crates/acp_thread/src/acp_thread.rs

@@ -3,9 +3,12 @@ mod diff;
 mod mention;
 mod terminal;
 
+use collections::HashSet;
 pub use connection::*;
 pub use diff::*;
+use language::language_settings::FormatOnSave;
 pub use mention::*;
+use project::lsp_store::{FormatTrigger, LspFormatTarget};
 use serde::{Deserialize, Serialize};
 pub use terminal::*;
 
@@ -1051,6 +1054,22 @@ impl AcpThread {
             })
     }
 
+    pub fn tool_call(&mut self, id: &acp::ToolCallId) -> Option<(usize, &ToolCall)> {
+        self.entries
+            .iter()
+            .enumerate()
+            .rev()
+            .find_map(|(index, tool_call)| {
+                if let AgentThreadEntry::ToolCall(tool_call) = tool_call
+                    && &tool_call.id == id
+                {
+                    Some((index, tool_call))
+                } else {
+                    None
+                }
+            })
+    }
+
     pub fn resolve_locations(&mut self, id: acp::ToolCallId, cx: &mut Context<Self>) {
         let project = self.project.clone();
         let Some((_, tool_call)) = self.tool_call_mut(&id) else {
@@ -1601,30 +1620,59 @@ impl AcpThread {
                         .collect::<Vec<_>>()
                 })
                 .await;
-            cx.update(|cx| {
-                project.update(cx, |project, cx| {
-                    project.set_agent_location(
-                        Some(AgentLocation {
-                            buffer: buffer.downgrade(),
-                            position: edits
-                                .last()
-                                .map(|(range, _)| range.end)
-                                .unwrap_or(Anchor::MIN),
-                        }),
-                        cx,
-                    );
-                });
 
+            project.update(cx, |project, cx| {
+                project.set_agent_location(
+                    Some(AgentLocation {
+                        buffer: buffer.downgrade(),
+                        position: edits
+                            .last()
+                            .map(|(range, _)| range.end)
+                            .unwrap_or(Anchor::MIN),
+                    }),
+                    cx,
+                );
+            })?;
+
+            let format_on_save = cx.update(|cx| {
                 action_log.update(cx, |action_log, cx| {
                     action_log.buffer_read(buffer.clone(), cx);
                 });
-                buffer.update(cx, |buffer, cx| {
+
+                let format_on_save = buffer.update(cx, |buffer, cx| {
                     buffer.edit(edits, None, cx);
+
+                    let settings = language::language_settings::language_settings(
+                        buffer.language().map(|l| l.name()),
+                        buffer.file(),
+                        cx,
+                    );
+
+                    settings.format_on_save != FormatOnSave::Off
                 });
                 action_log.update(cx, |action_log, cx| {
                     action_log.buffer_edited(buffer.clone(), cx);
                 });
+                format_on_save
             })?;
+
+            if format_on_save {
+                let format_task = project.update(cx, |project, cx| {
+                    project.format(
+                        HashSet::from_iter([buffer.clone()]),
+                        LspFormatTarget::Buffers,
+                        false,
+                        FormatTrigger::Save,
+                        cx,
+                    )
+                })?;
+                format_task.await.log_err();
+
+                action_log.update(cx, |action_log, cx| {
+                    action_log.buffer_edited(buffer.clone(), cx);
+                })?;
+            }
+
             project
                 .update(cx, |project, cx| project.save_buffer(buffer, cx))?
                 .await