diff --git a/plugins/kanban/dashboard/dist/index.js b/plugins/kanban/dashboard/dist/index.js
index 1f0b4c6d3b5..71adc77a666 100644
--- a/plugins/kanban/dashboard/dist/index.js
+++ b/plugins/kanban/dashboard/dist/index.js
@@ -2398,8 +2398,11 @@
             ? h("div", { className: "hermes-kanban-run-error" }, r.error)
             : null,
           r.metadata
-            ? h("code", { className: "hermes-kanban-run-meta" },
-                JSON.stringify(r.metadata))
+            ? h("div", { className: "hermes-kanban-run-meta-block" },
+                h("div", { className: "hermes-kanban-run-meta-label" }, "Metadata"),
+                h("code", { className: "hermes-kanban-run-meta" },
+                  JSON.stringify(r.metadata, null, 2)),
+              )
             : null,
         );
       }),
diff --git a/plugins/kanban/dashboard/dist/style.css b/plugins/kanban/dashboard/dist/style.css
index cb88bdfa5dd..3233facb53c 100644
--- a/plugins/kanban/dashboard/dist/style.css
+++ b/plugins/kanban/dashboard/dist/style.css
@@ -863,15 +863,37 @@
   padding: 0.15rem 0 0;
   font-family: var(--font-mono, ui-monospace, monospace);
 }
+/* Run metadata is a secondary detail panel. Render it as a clearly-labeled
+ * sub-block with a thin left rule, capped height, and muted treatment so
+ * a verbose JSON blob (e.g. changed_files + URLs from a writer task) does
+ * not visually swamp the parent run row or get mistaken for a crash dump.
+ * See issue #19548. */
+.hermes-kanban-run-meta-block {
+  margin-top: 0.4rem;
+  padding: 0.25rem 0.5rem;
+  border-left: 2px solid var(--color-border);
+  background: transparent;
+}
+.hermes-kanban-run-meta-label {
+  font-size: 0.65rem;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.06em;
+  color: var(--color-muted-foreground);
+  padding-bottom: 0.15rem;
+}
 .hermes-kanban-run-meta {
   display: block;
+  max-height: 8.5rem;
+  overflow: auto;
   font-size: 0.72rem;
   line-height: 1.5;
-  padding: 0.15rem 0 0;
+  padding: 0;
   color: var(--color-muted-foreground);
   white-space: pre-wrap;
   word-break: break-word;
   font-family: var(--font-mono, ui-monospace, monospace);
+  background: transparent;
 }
 
 /* -------------------------------------------------------------------------
diff --git a/tests/plugins/test_kanban_dashboard_plugin.py b/tests/plugins/test_kanban_dashboard_plugin.py
index 0fc6c493c14..9eb4ac45a97 100644
--- a/tests/plugins/test_kanban_dashboard_plugin.py
+++ b/tests/plugins/test_kanban_dashboard_plugin.py
@@ -1785,3 +1785,51 @@ def test_dashboard_lane_head_preserves_assignee_casing():
         "Lane head must not visually uppercase profile names — see #21320 "
         "and the explanatory comment in the CSS rule."
     )
+
+
+# ---------------------------------------------------------------------------
+# Built-asset regressions for the dashboard's run-history rendering
+# (issue #19548 — completed-run metadata used to render as a large pale box
+# that read like a crash dump). The plugin ships built-only, so we lock in
+# the rendered shape with static assertions on dist/index.js + dist/style.css.
+# ---------------------------------------------------------------------------
+
+
+def _dashboard_dist_path(name: str) -> Path:
+    repo_root = Path(__file__).resolve().parents[2]
+    p = repo_root / "plugins" / "kanban" / "dashboard" / "dist" / name
+    assert p.exists(), f"dashboard asset missing: {p}"
+    return p
+
+
+def test_run_metadata_pretty_printed_with_label():
+    """Run-history metadata is pretty-printed JSON inside a labeled sub-block."""
+    js = _dashboard_dist_path("index.js").read_text(encoding="utf-8")
+    # Pretty-printed JSON (indent=2) so a writer task's changed_files +
+    # URLs blob doesn't render as one wall-of-text monoline.
+    assert "JSON.stringify(r.metadata, null, 2)" in js
+    # Explicit label so the panel reads as auxiliary detail, not a crash dump.
+    assert '"hermes-kanban-run-meta-label"' in js
+    assert '"Metadata"' in js
+    # Wrapped in the labelled meta block container.
+    assert '"hermes-kanban-run-meta-block"' in js
+
+
+def test_run_metadata_secondary_styling():
+    """Metadata block is capped, transparent, and visually secondary."""
+    css = _dashboard_dist_path("style.css").read_text(encoding="utf-8")
+    # The label class exists with muted-foreground treatment.
+    assert ".hermes-kanban-run-meta-label" in css
+    # Container styling: thin left rule, no opaque highlighted fill that
+    # could be mistaken for an error/warning panel.
+    assert ".hermes-kanban-run-meta-block" in css
+    block_start = css.index(".hermes-kanban-run-meta-block {")
+    block_decl = css[block_start : block_start + 400]
+    assert "background: transparent" in block_decl
+    assert "border-left" in block_decl
+    # Cap meta height so verbose JSON doesn't sprawl across the run row.
+    meta_start = css.index(".hermes-kanban-run-meta {")
+    meta_decl = css[meta_start : meta_start + 400]
+    assert "max-height" in meta_decl
+    assert "overflow: auto" in meta_decl
+    assert "color: var(--color-muted-foreground)" in meta_decl