diff --git a/docs/2-handbook/swarm/ui.md b/docs/2-handbook/swarm/ui.md
index 1fdd74d5..36ca935d 100644
--- a/docs/2-handbook/swarm/ui.md
+++ b/docs/2-handbook/swarm/ui.md
@@ -605,8 +605,9 @@ and base branch, and what a reviewer or merger filters on:
   decision, on the PR's current head, neither stale nor dismissed, and from a
   reviewer whose approval the rule accepts. A reviewer whose latest review asks for changes shows **changes
   requested**.
-- **has all approvals**: the approvals meet the rule. A PR into a branch with no
-  protection rule has nothing to approve, so it has them all.
+- **approved**: the approvals meet the rule. A PR into a branch with no
+  protection rule has nothing to approve, so it counts as approved.
+- **diff**: the lines the PR adds and removes (`+120 −8`), as the forge counts them.
 - **conflicts**: the forge can't merge the PR as it stands.
 - **protected base**: the base branch has a protection rule. A stacked PR targets a
   feature branch, so filtering this to **no** lists them.
diff --git a/frontend/packages/swarm-ui/src/pages/PrReportPage.tsx b/frontend/packages/swarm-ui/src/pages/PrReportPage.tsx
index 9994e32b..0d8d1f1a 100644
--- a/frontend/packages/swarm-ui/src/pages/PrReportPage.tsx
+++ b/frontend/packages/swarm-ui/src/pages/PrReportPage.tsx
@@ -24,6 +24,8 @@ import { TableSkeleton } from "../ui/table/TableSkeleton.js";
 import { ALL_REPOS, repoOptions } from "./issue-report-repo.js";
 import {
   approvalsText,
+  diffSize,
+  diffText,
   hasAllApprovals,
   prReportUrl,
   yesNo,
@@ -124,7 +126,7 @@ const COLUMNS: TableColumn<PrReportRow>[] = [
   },
   {
     key: "approved",
-    header: "has all approvals",
+    header: "approved",
     render: (r) =>
       hasAllApprovals(r) ? <Badge tone="positive" value="yes" /> : "no",
     sortBy: (r) => Number(hasAllApprovals(r)),
@@ -156,6 +158,12 @@ const COLUMNS: TableColumn<PrReportRow>[] = [
     filterValues: (r) => [r.ci ?? "none"],
     filterMode: "multiselect",
   },
+  {
+    key: "diff",
+    header: "diff",
+    render: (r) => diffText(r),
+    sortBy: (r) => diffSize(r),
+  },
   {
     key: "updated",
     header: "updated",
diff --git a/frontend/packages/swarm-ui/src/pages/pr-report.ts b/frontend/packages/swarm-ui/src/pages/pr-report.ts
index 6c11415f..6b8e8556 100644
--- a/frontend/packages/swarm-ui/src/pages/pr-report.ts
+++ b/frontend/packages/swarm-ui/src/pages/pr-report.ts
@@ -17,6 +17,9 @@ export interface PrReportRow {
   head_branch: string;
   created_unix: number | null;
   updated_unix: number | null;
+  /** Lines the PR adds and removes. */
+  additions: number | null;
+  deletions: number | null;
   /** The forge's draft flag. */
   wip: boolean;
   has_conflicts: boolean;
@@ -52,6 +55,18 @@ export function hasAllApprovals(row: PrReportRow): boolean {
   return row.approvals >= row.required_approvals;
 }
 
+/** The diff size cell: lines added and removed, `+120 −8`. A count the forge
+ * did not give reads as a dash. */
+export function diffText(row: PrReportRow): string {
+  if (row.additions === null && row.deletions === null) return "—";
+  return `+${row.additions ?? 0} −${row.deletions ?? 0}`;
+}
+
+/** What the diff column sorts on: lines changed in all. */
+export function diffSize(row: PrReportRow): number {
+  return (row.additions ?? 0) + (row.deletions ?? 0);
+}
+
 /** The approvals cell: how many of the rule's approvals the PR has, or a dash
  * when its base branch asks for none. */
 export function approvalsText(row: PrReportRow): string {
diff --git a/frontend/packages/swarm-ui/test/pr-report.test.mjs b/frontend/packages/swarm-ui/test/pr-report.test.mjs
index 64fe22c6..a39648a2 100644
--- a/frontend/packages/swarm-ui/test/pr-report.test.mjs
+++ b/frontend/packages/swarm-ui/test/pr-report.test.mjs
@@ -3,6 +3,8 @@ import assert from "node:assert/strict";
 import { test } from "node:test";
 import {
   approvalsText,
+  diffSize,
+  diffText,
   hasAllApprovals,
   prReportUrl,
   yesNo,
@@ -52,6 +54,15 @@ test("an unprotected base, or a rule asking for none, shows only what it has", (
   );
 });
 
+test("the diff reads as lines added and removed, and sorts on both", () => {
+  assert.equal(diffText({ additions: 120, deletions: 8 }), "+120 −8");
+  assert.equal(diffText({ additions: 0, deletions: 3 }), "+0 −3");
+  assert.equal(diffText({ additions: 5, deletions: null }), "+5 −0");
+  assert.equal(diffText({ additions: null, deletions: null }), "—");
+  assert.equal(diffSize({ additions: 120, deletions: 8 }), 128);
+  assert.equal(diffSize({ additions: null, deletions: null }), 0);
+});
+
 test("a PR has all approvals when it meets the rule, and an unprotected base always does", () => {
   assert.equal(hasAllApprovals(row({})), false);
   assert.equal(hasAllApprovals(row({ approvals: 2 })), true);
diff --git a/swarm-controller/src/forge/pr_report.rs b/swarm-controller/src/forge/pr_report.rs
index 801572a8..3e59af59 100644
--- a/swarm-controller/src/forge/pr_report.rs
+++ b/swarm-controller/src/forge/pr_report.rs
@@ -41,6 +41,9 @@ pub struct PrReportRow {
     pub head_branch: String,
     pub created_unix: Option<i64>,
     pub updated_unix: Option<i64>,
+    /// Lines the PR adds and removes, as the forge counts them.
+    pub additions: Option<i64>,
+    pub deletions: Option<i64>,
     /// The forge's draft flag (setting a `WIP:` title is what sets it).
     pub wip: bool,
     /// The forge cannot merge the PR as it is: its head conflicts with the
@@ -200,6 +203,8 @@ fn row(
         head_branch: head.r#ref.clone().unwrap_or_default(),
         created_unix: pr.created_at.as_ref().map(|t| t.unix_timestamp()),
         updated_unix: pr.updated_at.as_ref().map(|t| t.unix_timestamp()),
+        additions: pr.additions,
+        deletions: pr.deletions,
         wip: pr.draft.unwrap_or(false),
         has_conflicts: pr.mergeable == Some(false),
         targets_protected_branch: protection.is_some(),
@@ -483,6 +488,8 @@ mod tests {
             "head": { "ref": "iris/thing", "sha": "h1" },
             "created_at": "2026-11-07T08:00:00Z",
             "updated_at": "2026-11-07T09:00:00Z",
+            "additions": 120,
+            "deletions": 8,
         }))
         .expect("a pull request");
         let status: CombinedStatus = serde_json::from_value(serde_json::json!({
@@ -504,6 +511,7 @@ mod tests {
         assert_eq!(r.author.as_deref(), Some("iris"));
         assert_eq!(r.requested_reviewers, ["argus"]);
         assert_eq!(r.updated_unix, Some(1_794_042_000));
+        assert_eq!((r.additions, r.deletions), (Some(120), Some(8)));
 
         // The same PR into a branch no rule names has nothing to approve.
         let r = row("o/r", &pr, &[], &reviews, &status).expect("a row");