diff --git a/tools/bend-fmt-lsp/src/formatter.ts b/tools/bend-fmt-lsp/src/formatter.ts
index 27129c6be..d2ef54bae 100644
--- a/tools/bend-fmt-lsp/src/formatter.ts
+++ b/tools/bend-fmt-lsp/src/formatter.ts
@@ -167,11 +167,13 @@ type BodyScope = { open: number; angle: number; end: number };
 type InlineBody = { at: number; scope?: BodyScope };
 
 // The tokens that start a body on the line of its `do`, `match`, `case` or
-// `def` header, `=>` lambda opener, `;` separator or `(` group opener. As in
-// `do IO<Unit>: a`, Bend pins the lines after it to the column of `a`.
+// `def` header, `=>` lambda opener, `;` separator, `(` group opener or
+// parenthesized `,` separator. As in `do IO<Unit>: a`, Bend pins the lines
+// after it to the column of `a`.
 function inlineBodies(lines: Line[]): InlineBody[][] {
   let open = 0;
   const angles = [0];
+  const parens: number[] = [];
   const bodyScopes: BodyScope[] = [];
   let header: { open: number; angle: number; typed: boolean } | null = null;
   return lines.map((line, row) => line.tokens.flatMap((token, index): InlineBody[] => {
@@ -183,11 +185,13 @@ function inlineBodies(lines: Line[]): InlineBody[][] {
     } else if (["(", "[", "{"].includes(token.text)) {
       open++;
       angles.push(0);
+      if (token.text === "(") parens.push(open);
       if (token.text === "(" && index + 1 < line.tokens.length) {
         bodyScopes.push({ open, angle: angles[open], end: lines.length });
         return [{ at: index + 1, scope: bodyScopes.at(-1) }];
       }
     } else if ([")", "]", "}"].includes(token.text)) {
+      if (parens.at(-1) === open) parens.pop();
       if (open > 0) angles.pop();
       open = Math.max(0, open - 1);
     } else if (ANGLES.has(token.text)) {
@@ -209,6 +213,10 @@ function inlineBodies(lines: Line[]): InlineBody[][] {
       // A leading closer/separator has no body statement to pin on this line.
       bodyScopes.pop()!.end = row - (index === 0 ? 1 : 0);
     }
+    if (token.text === "," && parens.at(-1) === open && angles[open] === 0 && index + 1 < line.tokens.length) {
+      bodyScopes.push({ open, angle: angles[open], end: lines.length });
+      return [{ at: index + 1, scope: bodyScopes.at(-1) }];
+    }
     return [];
   }));
 }
diff --git a/tools/bend-fmt-lsp/src/test/formatter.test.ts b/tools/bend-fmt-lsp/src/test/formatter.test.ts
index 33d70a432..6b7f1ec7a 100644
--- a/tools/bend-fmt-lsp/src/test/formatter.test.ts
+++ b/tools/bend-fmt-lsp/src/test/formatter.test.ts
@@ -8,7 +8,8 @@ import { fileURLToPath } from "node:url";
 import { formatBend } from "../formatter.js";
 
 // Bend pins the lines after a body that shares a line with its `do`, `match`,
-// `case` or `def` header, `=>` lambda opener or `;` to that body's column. [source, formatted]
+// `case` or `def` header, `=>` lambda opener, `;`, `(` or parenthesized `,`
+// to that body's column. [source, formatted]
 const pinned = [
   [
     "import Base\ndef f(a:Array<U32>)->Array<U32>: b=a; b[0]<-7\n                                      b[1]<-8\n\ndef main() -> Array<U32>:\n  f([0 : U32 * 2n])\n",
@@ -76,6 +77,14 @@ const pinned = [
     "import Base\ndef f(a: Array<U32>, b: Bool, c: Bool) -> Array<U32>:\n    match b:\n      case True{}: match c:\n                     case True{}: a[0] <- 7\n                                  a[1] <- 8\n                     case False{}: a\n      case False{}: a\n\ndef main() -> Array<U32>:\n    f([0 : U32*2n], True{}, True{})\n",
     "import Base\ndef f(a: Array<U32>, b: Bool, c: Bool) -> Array<U32>:\n  match b:\n    case True{}: match c:\n                   case True{}: a[0] <- 7\n                                a[1] <- 8\n                   case False{}: a\n    case False{}: a\n\ndef main() -> Array<U32>:\n  f([0 : U32 * 2n], True{}, True{})\n",
   ],
+  [
+    "import Base\ndef main()->U32 & Array<U32>:\n  a = [0 : U32 * 2n]\n  (17,a[0]<-3\n      a[1]<-5)\n",
+    "import Base\ndef main() -> U32 & Array<U32>:\n  a = [0 : U32 * 2n]\n  (17, a[0] <- 3\n       a[1] <- 5)\n",
+  ],
+  [
+    "import Base\ndef finish(p:U32 & Array<U32>,n:U32)->Array<U32>:\n  (x,a) = p\n  a[0] <- U32.add(x,n)\ndef main()->Array<U32>:\n  a = [0 : U32 * 2n]\n  finish((17,a[0]<-3\n             a[1]<-5),\n    11)\n",
+    "import Base\ndef finish(p: U32 & Array<U32>, n: U32) -> Array<U32>:\n  (x, a) = p\n  a[0] <- U32.add(x, n)\ndef main() -> Array<U32>:\n  a = [0 : U32 * 2n]\n  finish((17, a[0] <- 3\n              a[1] <- 5),\n    11)\n",
+  ],
 ];
 
 test("moves pinned lines as far as the body they line up with", () => {