diff --git a/runsum.mts b/runsum.mts
new file mode 100644
index 0000000..5eaf338
--- /dev/null
+++ b/runsum.mts
@@ -0,0 +1,119 @@
+/**
+ * One-off: summarise a project's commits from the command line.
+ *
+ * Imports the same PURE modules the app uses — batch.ts, preamble.ts,
+ * prompt.ts — so the prompts, the batching and the index-matched parsing are
+ * byte-identical to what the "Summarise" button does. Only the surrounding
+ * plumbing (which carries `server-only`) is reimplemented here.
+ */
+import PocketBase from "pocketbase";
+
+import { BATCH_SIZE, buildBatchPrompt, chunk, parseBatchResponse } from "./src/lib/ai/batch";
+import { PROMPT_VERSION } from "./src/lib/ai/preamble";
+import { buildSystemPrompt } from "./src/lib/ai/prompt";
+import { stripThinking } from "./src/lib/ai/think-strip";
+
+async function main() {
+  const pb = new PocketBase(process.env.NEXT_PUBLIC_PB_URL!);
+  pb.autoCancellation(false);
+  await pb
+    .collection("_superusers")
+    .authWithPassword(process.env.PB_SUPERUSER_EMAIL!, process.env.PB_SUPERUSER_PASSWORD!);
+
+  const settings = await pb.collection("settings").getFirstListItem("id != ''");
+  const key: string = settings.ai_api_key ?? "";
+  const model: string = settings.ai_model || "MiniMax-M2";
+  if (!key) throw new Error("No API key configured — paste it in Settings first.");
+
+  const system = buildSystemPrompt(settings.ai_system_prompt_extra ?? "");
+
+  const pending = await pb.collection("commits").getFullList({
+    filter: [
+      "is_merge = false",
+      `(summary = "" || summary_version < ${PROMPT_VERSION})`,
+      "summary_attempts < 3",
+    ].join(" && "),
+    sort: "-authored_at",
+    fields: "id,subject,type,scope,summary_attempts",
+  });
+
+  console.log(`provider=${settings.ai_provider} model=${model}`);
+  console.log(`pending commits: ${pending.length}`);
+  if (pending.length === 0) return;
+
+  const batches = chunk(
+    pending.map((c) => ({
+      id: c.id,
+      subject: (c.subject as string) || "",
+      type: (c.type as string) || "other",
+      scope: (c.scope as string) || "",
+    })),
+    BATCH_SIZE
+  );
+
+  let summarised = 0;
+  let missing = 0;
+  let inTok = 0;
+  let outTok = 0;
+
+  for (const [index, batch] of batches.entries()) {
+    process.stdout.write(`  batch ${index + 1}/${batches.length} … `);
+
+    let text = "";
+    try {
+      const res = await fetch("https://api.minimax.io/v1/chat/completions", {
+        method: "POST",
+        headers: { "content-type": "application/json", authorization: `Bearer ${key}` },
+        body: JSON.stringify({
+          model,
+          max_tokens: 4096,
+          n: 1,
+          messages: [
+            { role: "system", content: system },
+            { role: "user", content: buildBatchPrompt(batch) },
+          ],
+        }),
+      });
+
+      if (!res.ok) {
+        console.log(`HTTP ${res.status} — ${(await res.text()).slice(0, 120)}`);
+        continue;
+      }
+
+      const json = await res.json();
+      text = stripThinking(json.choices?.[0]?.message?.content ?? "");
+      inTok += json.usage?.prompt_tokens ?? 0;
+      outTok += json.usage?.completion_tokens ?? 0;
+    } catch (error) {
+      console.log(`failed — ${(error as Error).message}`);
+      continue;
+    }
+
+    const parsed = parseBatchResponse(text, batch);
+
+    for (const commit of batch) {
+      const summary = parsed.get(commit.id);
+      if (!summary) {
+        missing += 1;
+        continue;
+      }
+      await pb.collection("commits").update(commit.id, {
+        summary,
+        summary_version: PROMPT_VERSION,
+        summary_attempts: 0,
+      });
+      summarised += 1;
+    }
+
+    console.log(`${parsed.size}/${batch.length}`);
+  }
+
+  console.log(`\nsummarised: ${summarised}`);
+  console.log(`not returned by the model: ${missing}`);
+  console.log(`tokens: ${inTok} in, ${outTok} out`);
+}
+
+main().catch((e) => {
+  console.error("FAILED:", e?.message ?? e);
+  process.exit(1);
+});
diff --git a/src/components/board/board.tsx b/src/components/board/board.tsx
index 927edae..6f3b45c 100644
--- a/src/components/board/board.tsx
+++ b/src/components/board/board.tsx
@@ -292,6 +292,16 @@ export function Board({
   return (
     <div className="flex-1 overflow-hidden" data-project={projectId}>
       <DndContext
+        // A STABLE id, not dnd-kit's default.
+        //
+        // Without it, dnd-kit derives the id of its accessibility description
+        // element from an internal counter that starts fresh on the server and
+        // is already advanced on the client. Every sortable card then renders
+        // aria-describedby="DndDescribedBy-0" server-side and
+        // aria-describedby="DndDescribedBy-3" client-side, and React reports a
+        // hydration mismatch for the whole tree. Pinning the id makes both
+        // sides agree.
+        id="board-dnd"
         sensors={sensors}
         onDragStart={onDragStart}
         onDragEnd={onDragEnd}