#3692: typed paragraphs break like Enter, still one command and one undo step

Ultrareview finding 2. MCP `type_text` with `paragraphs: true` sent one raw
text.insert with `\r` breaks, which skipped Enter: a break could land in a
one-line, check-box or drop-down content control (text.newParagraph refuses
there), and Enter's AutoFormat (--- borders, +---+ tables) no longer ran.

text.insert takes `paragraphs: true`: each line is typed raw and each break
runs text.newParagraph's own implementation (`enter`), inside the one
command, so there is one checkpoint. Where Enter would refuse, the command
fails and Session::run puts the document and history back (all or nothing).
Enter's AutoFormat normally records the plain Enter as its own undo step
after the fact (push_undo, a whole-document clone); inside typed paragraphs
that step is skipped, so AutoFormatted lines add no snapshot each. MCP sends
`paragraphs: true` and keeps MAX_TYPED_PARAGRAPHS.

Tests: mcp type_text_paragraphs_are_refused_in_a_one_line_control,
type_text_paragraphs_autoformat_like_enter_in_one_undo_step.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

crates/engine/src/cmd/text.rs

@@ -10,7 +10,7 @@ use crate::{CmdError, CmdResult, CommandSpec, Selection, Session, p};
 
 pub fn specs() -> Vec<CommandSpec> {
     vec![
-        CommandSpec::new("text.insert", "Type Text", "Editing", insert).params(r#"{"text": string}"#),
+        CommandSpec::new("text.insert", "Type Text", "Editing", insert).params(r#"{"text": string, "raw"?: bool, "paragraphs"?: bool}"#),
         CommandSpec::new("text.newParagraph", "New Paragraph", "Editing", new_paragraph).key("Enter"),
         CommandSpec::new("text.lineBreak", "Line Break", "Editing", |s, _| ins_char(s, '\n')).key("Shift+Enter"),
         CommandSpec::new("text.pageBreak", "Page Break", "Insert › Pages", |s, _| ins_char(s, PAGE_BREAK)).key("Mod+Enter"),
@@ -99,6 +99,9 @@ fn typing_options(s: &mut Session, text: &str) {
 fn insert(s: &mut Session, v: &Value) -> CmdResult {
     let text = p::req_str(v, "text")?;
     let raw = p::bool(v, "raw").unwrap_or(false);
+    if p::bool(v, "paragraphs").unwrap_or(false) {
+        return insert_paragraphs(s, text);
+    }
     typing_options(s, text);
     let t = if raw { None } else { autoformat(s, text) };
     type_text(s, t.as_deref().unwrap_or(text))?;
@@ -576,30 +579,65 @@ fn new_paragraph(s: &mut Session, _: &Value) -> CmdResult {
     if super::controls::refuses_paragraph(s) {
         return sel_result(s);
     }
+    enter(s, true)?;
+    sel_result(s)
+}
+
+/// `text.insert` with `paragraphs`: each line typed as it is (`raw`), and between lines the
+/// paragraph break Enter makes ([`enter`]: its AutoFormat and AutoCorrect), all in one command, so
+/// one undo step instead of a command and a whole-document snapshot per line (#3692). Where
+/// Enter would do nothing (a one-line control, a check box, a list) the text is refused and,
+/// like any failed command, nothing of it stays.
+fn insert_paragraphs(s: &mut Session, text: &str) -> CmdResult {
+    typing_options(s, text);
+    let text = text.replace("\r\n", "\n");
+    for (i, line) in text.split(['\n', '\r', '\u{2029}']).enumerate() {
+        if i > 0 {
+            if super::controls::refuses_paragraph(s) {
+                return Err(CmdError::Disabled("text.insert: this content control takes no paragraph breaks".into()));
+            }
+            enter(s, false)?;
+        }
+        if !line.is_empty() {
+            type_text(s, line)?;
+        }
+    }
+    sel_result(s)
+}
+
+/// Enter's paragraph break once a control has allowed it: `=rand()` sample text, AutoFormat of a
+/// border or table line, AutoCorrect of the word it ends, else a plain split. With `undo_step`
+/// an AutoFormat is recorded as its own undo step after the plain Enter, as in Word; without it
+/// (typed paragraphs, one undo step for all) no extra snapshot is taken.
+fn enter(s: &mut Session, undo_step: bool) -> Result<(), CmdError> {
     super::controls::prepare_edit(s)?;
     if let Some(text) = sample_text(s) {
         let end = s.sel.focus.clone();
         s.sel = Selection { anchor: Pos { off: 0, ..end.clone() }, focus: end };
-        type_text(s, &text)?;
-        return sel_result(s);
+        return type_text(s, &text);
     }
     let mut at = delete_selection(s)?;
     let auto = border_line(s, &at).map(EnterAutoFormat::Border).or_else(|| table_line(s, &at).map(EnterAutoFormat::Table));
     if let Some(auto) = auto {
         // Word: Undo right after reverts only the AutoFormat, so the typed characters come back
         // and the Enter stays. Record that plain Enter as its own undo step.
-        let (doc, sel) = (s.doc.clone(), s.sel.clone());
-        let new = split_para(s, &at)?;
-        s.sel = Selection::caret(new);
-        let plain_doc = std::mem::replace(&mut s.doc, doc);
-        let plain_sel = std::mem::replace(&mut s.sel, sel);
+        let plain = if undo_step {
+            let (doc, sel) = (s.doc.clone(), s.sel.clone());
+            let new = split_para(s, &at)?;
+            s.sel = Selection::caret(new);
+            Some((std::mem::replace(&mut s.doc, doc), std::mem::replace(&mut s.sel, sel)))
+        } else {
+            None
+        };
         match auto {
             EnterAutoFormat::Border(line) => apply_border_line(s, &at, line)?,
             EnterAutoFormat::Table(cols) => apply_table_line(s, &at, &cols)?,
         }
         s.goal_x = None;
-        s.push_undo("AutoFormat", plain_doc, plain_sel);
-        return sel_result(s);
+        if let Some((plain_doc, plain_sel)) = plain {
+            s.push_undo("AutoFormat", plain_doc, plain_sel);
+        }
+        return Ok(());
     }
     // Enter finishes a word like a space does ("teh" → "the", sentence capitals, links).
     if s.sel.is_collapsed() && at.off > 0 {
@@ -610,7 +648,7 @@ fn new_paragraph(s: &mut Session, _: &Value) -> CmdResult {
     let new = split_para(s, &at)?;
     s.sel = Selection::caret(new);
     s.goal_x = None;
-    sel_result(s)
+    Ok(())
 }
 
 /// In a table: next cell (adds a row at the end). At the start of a list item: demote. Else a tab.

crates/mcp/src/tests.rs

@@ -120,7 +120,7 @@ fn headless_sessions_keep_the_dictionary_in_memory() {
     assert!(h.session.user_dict_path.is_none());
 }
 
-/// A backend that keeps every command it is sent and refuses text with a paragraph break.
+/// A backend that keeps every command it is sent and refuses typed paragraphs.
 struct RefusesParagraph {
     calls: std::sync::Arc<std::sync::Mutex<Vec<Value>>>,
 }
@@ -128,8 +128,8 @@ struct RefusesParagraph {
 impl crate::backend::Backend for RefusesParagraph {
     fn call(&mut self, _method: &str, params: Value) -> Result<Value, String> {
         self.calls.lock().unwrap().push(params.clone());
-        match params["params"]["text"].as_str() {
-            Some(t) if t.contains('\r') => Err("paragraph break refused".into()),
+        match params["params"]["paragraphs"].as_bool() {
+            Some(true) => Err("paragraph break refused".into()),
             _ => Ok(json!({"ok": true})),
         }
     }
@@ -153,7 +153,8 @@ fn type_text_stops_at_a_refused_paragraph_break() {
     let calls = calls.lock().unwrap();
     assert_eq!(calls.len(), 1, "{calls:?}");
     assert_eq!(calls[0]["command"], "text.insert");
-    assert_eq!(calls[0]["params"]["text"], "one\rtwo");
+    assert_eq!(calls[0]["params"]["text"], "one\ntwo");
+    assert_eq!(calls[0]["params"]["paragraphs"], true);
 }
 
 /// #3692: typed paragraphs are one edit and one undo step, not a command (and a whole-document
@@ -179,3 +180,46 @@ fn type_text_paragraphs_are_one_undo_step_with_a_line_cap() {
     assert_eq!(r["result"]["isError"], true, "{r}");
     assert!(calls.lock().unwrap().is_empty(), "refused before any command");
 }
+
+/// Ultrareview of #3692: each typed paragraph break is Enter's own (text.newParagraph's
+/// implementation), so a one-line content control refuses it, and all of the text with it.
+#[test]
+fn type_text_paragraphs_are_refused_in_a_one_line_control() {
+    let mut s = Server::new(Box::new(Headless::default()));
+    tool(&mut s, "new_document", json!({}));
+    tool(&mut s, "type_text", json!({"text": "Name: "}));
+    tool(&mut s, "execute", json!({"command": "developer.plainText", "params": {"tag": "name"}}));
+    tool(&mut s, "execute", json!({"command": "caret.right"}));
+    let before = tool(&mut s, "get_text", json!({}))["text"].clone();
+    let r = call(&mut s, 13, "tools/call", json!({"name": "type_text", "arguments": {"text": "Ada\nLovelace", "paragraphs": true}}));
+    assert_eq!(r["result"]["isError"], true, "{r}");
+    assert_eq!(tool(&mut s, "get_text", json!({}))["text"], before, "nothing typed");
+    assert_eq!(tool(&mut s, "inspect_document", json!({}))["blocks"].as_array().unwrap().len(), 1);
+}
+
+/// Ultrareview of #3692: Enter's AutoFormat runs on each typed paragraph break ("---" becomes a
+/// border, "+---+---+" a table), and the lines are still one undo step however many of them
+/// AutoFormat changes.
+#[test]
+fn type_text_paragraphs_autoformat_like_enter_in_one_undo_step() {
+    let mut s = Server::new(Box::new(Headless::default()));
+    tool(&mut s, "new_document", json!({}));
+    tool(&mut s, "type_text", json!({"text": "Above\n---\nBelow\n+---+---+\nCell", "paragraphs": true}));
+    let blocks = tool(&mut s, "inspect_document", json!({}))["blocks"].clone();
+    let blocks = blocks.as_array().unwrap();
+    assert_eq!(blocks[0]["text"], "Above", "{blocks:?}");
+    assert!(blocks[0]["props"]["borders"]["bottom"].is_object(), "--- is a border: {blocks:?}");
+    assert_eq!(blocks[1]["text"], "Below", "{blocks:?}");
+    assert_eq!(blocks[2]["type"], "table", "+---+---+ is a table: {blocks:?}");
+    assert!(blocks[2].to_string().contains("Cell"), "typing goes on in its first cell: {blocks:?}");
+    tool(&mut s, "execute", json!({"command": "edit.undo"}));
+    assert_eq!(tool(&mut s, "inspect_document", json!({}))["blocks"].as_array().unwrap().len(), 1, "one Undo");
+    assert_eq!(tool(&mut s, "get_text", json!({}))["text"].as_str().unwrap().trim(), "");
+
+    // Many AutoFormatted lines: still one undo step (no snapshot per line).
+    let lines: Vec<&str> = (0..500).flat_map(|_| ["Text", "==="]).collect();
+    tool(&mut s, "type_text", json!({"text": lines.join("\n"), "paragraphs": true}));
+    assert_eq!(tool(&mut s, "inspect_document", json!({}))["blocks"].as_array().unwrap().len(), 501);
+    tool(&mut s, "execute", json!({"command": "edit.undo"}));
+    assert_eq!(tool(&mut s, "inspect_document", json!({}))["blocks"].as_array().unwrap().len(), 1, "one Undo");
+}

crates/mcp/src/tools.rs

@@ -232,15 +232,16 @@ pub fn call_tool(b: &mut dyn Backend, name: &str, a: &Value) -> ToolResult {
         "type_text" => {
             let t = st("text").unwrap_or("");
             if a.get("paragraphs").and_then(Value::as_bool).unwrap_or(false) {
-                // One `text.insert`: `\r` is a paragraph break there (Enter's split), so the
-                // lines go in as one edit and one undo step, all or nothing, instead of a command
-                // (and a whole-document undo snapshot) per line.
+                // One `text.insert` with `paragraphs`: each break is Enter's own (its AutoFormat,
+                // and its refusal in a one-line control), but the lines go in as one edit and one
+                // undo step, all or nothing, instead of a command (and a whole-document undo
+                // snapshot) per line.
                 let t = t.replace("\r\n", "\n").replace('\r', "\n");
                 let lines = t.split(['\n', '\u{2029}']).count();
                 if lines > MAX_TYPED_PARAGRAPHS {
                     return ToolResult::error(format!("`text` has {lines} lines; type at most {MAX_TYPED_PARAGRAPHS} paragraphs per call"));
                 }
-                wrap(exec(b, "text.insert", json!({"text": t.replace('\n', "\r"), "raw": true})))
+                wrap(exec(b, "text.insert", json!({"text": t, "raw": true, "paragraphs": true})))
             } else {
                 wrap(exec(b, "text.insert", json!({"text": t, "raw": true})))
             }