diff --git a/.github/workflows/pr-trusted.yml b/.github/workflows/pr-trusted.yml
index 56b6f594c12..228ac3bd4b7 100644
--- a/.github/workflows/pr-trusted.yml
+++ b/.github/workflows/pr-trusted.yml
@@ -585,8 +585,16 @@ jobs:
             group_label: workspaces-a (2/2)
             shard_index: 1
             shard_count: 2
+          # workspaces-b became the slowest check (499-593s) once the server
+          # shards were rebalanced: the db project alone was 168-250s of its
+          # 436-513s of vitest time (PR runs 38084171761, 38083084276 and
+          # 38083020834, 2026-10-10). The db project now runs as its own
+          # workspaces-c lane; the rest of workspaces-b is ~265-275s of
+          # vitest time, so both jobs land near 300-350s with setup.
           - group: general-workspaces-b
             group_label: workspaces-b
+          - group: general-workspaces-c
+            group_label: workspaces-c
 
     steps:
       - name: Checkout repository
diff --git a/.github/workflows/release-verify.yml b/.github/workflows/release-verify.yml
index 492b7e62b47..3fd321edb68 100644
--- a/.github/workflows/release-verify.yml
+++ b/.github/workflows/release-verify.yml
@@ -174,6 +174,9 @@ jobs:
             shard_count: 2
           - group: general-workspaces-b
             group_label: workspaces-b
+          # Keep parity with pr.yml: the db project runs as its own lane.
+          - group: general-workspaces-c
+            group_label: workspaces-c
 
     steps:
       - name: Checkout repository
diff --git a/scripts/__tests__/release-verify-workflow.test.mjs b/scripts/__tests__/release-verify-workflow.test.mjs
index 043636edb91..9d00a15b79e 100644
--- a/scripts/__tests__/release-verify-workflow.test.mjs
+++ b/scripts/__tests__/release-verify-workflow.test.mjs
@@ -505,7 +505,7 @@ test("release verify workflow covers the same split test surface as stable PR ve
   assert.match(buildJob, /persist-credentials: false/);
   assert.doesNotMatch(buildJob, /cache: pnpm/);
 
-  for (const group of ["general-server-without-chat-or-native-runner", "general-chat", "general-workspaces-a", "general-workspaces-b"]) {
+  for (const group of ["general-server-without-chat-or-native-runner", "general-chat", "general-workspaces-a", "general-workspaces-b", "general-workspaces-c"]) {
     assert.match(verifyWorkflow, new RegExp(`group: ${group}`));
   }
   for (const [group, count] of [["general-server-without-chat-or-native-runner", 10], ["general-chat", 3]]) {
diff --git a/scripts/__tests__/run-vitest-stable-shard.test.mjs b/scripts/__tests__/run-vitest-stable-shard.test.mjs
index a044c67c151..3dd3e9680e0 100644
--- a/scripts/__tests__/run-vitest-stable-shard.test.mjs
+++ b/scripts/__tests__/run-vitest-stable-shard.test.mjs
@@ -107,10 +107,12 @@ test("general shards retain scripts and route-named suites outside the serialize
   ]) assert.ok(general.selectedGeneralServerSuites.includes(file), `missing configured server suite: ${file}`);
 });
 
-test("shard flags are rejected for the workspaces-b group", () => {
-  const result = dryRun(["--mode", "general", "--group", "general-workspaces-b", "--shard-index", "0", "--shard-count", "3"]);
-  assert.notEqual(result.status, 0, "workspaces-b must not accept shard flags");
-});
+for (const group of ["general-workspaces-b", "general-workspaces-c"]) {
+  test(`shard flags are rejected for the ${group} group`, () => {
+    const result = dryRun(["--mode", "general", "--group", group, "--shard-index", "0", "--shard-count", "3"]);
+    assert.notEqual(result.status, 0, `${group} must not accept shard flags`);
+  });
+}
 
 test("workspace lanes cover every non-server project in the root Vitest configuration", () => {
   const config = readFileSync(path.join(repoRoot, "vitest.config.ts"), "utf8");
@@ -118,11 +120,81 @@ test("workspace lanes cover every non-server project in the root Vitest configur
   assert.ok(roots.includes("server"), "expected the explicit root Vitest project list");
   const expected = roots.filter(root => root !== "server")
     .map(root => JSON.parse(readFileSync(path.join(repoRoot, root, "package.json"), "utf8")).name).sort();
-  const actual = ["general-workspaces-a", "general-workspaces-b"]
+  const actual = ["general-workspaces-a", "general-workspaces-b", "general-workspaces-c"]
     .flatMap(group => dryRunJson(["--mode", "general", "--group", group]).workspaceProjects).sort();
   assert.deepEqual(actual, expected, "no configured project may be silently omitted or run twice");
 });
 
+// Collects every `- group:` matrix entry in a workflow with the keys it sets.
+// Comment and blank lines are dropped first, and an entry ends only when the
+// indentation returns to the item level, so a comment between two keys cannot
+// hide a shard setting from the assertions below.
+function matrixEntries(text) {
+  const entries = [];
+  let current = null;
+  for (const line of text.split("\n")) {
+    if (/^\s*(#|$)/.test(line)) continue;
+    const indent = line.match(/^ */)[0].length;
+    const item = line.match(/^ *- group: (\S+)/);
+    if (item) {
+      current = { group: item[1], indent, keys: ["group"] };
+      entries.push(current);
+      continue;
+    }
+    if (!current) continue;
+    if (indent <= current.indent) { current = null; continue; }
+    const key = line.match(/^ *([A-Za-z_]+):/);
+    if (key) current.keys.push(key[1]);
+  }
+  return entries;
+}
+
+test("matrixEntries sees shard keys that sit behind comments or later in the entry", () => {
+  const entries = matrixEntries([
+    "        include:",
+    "          - group: general-workspaces-b",
+    "            group_label: workspaces-b",
+    "            # a comment between keys must not hide the shard setting",
+    "            shard_index: 0",
+    "",
+    "            shard_count: 3",
+    "          - group: general-workspaces-c",
+    "            group_label: workspaces-c",
+    "      steps:",
+    "        - name: unrelated",
+    "          shard_index: 9",
+  ].join("\n"));
+  assert.deepEqual(entries.map(entry => entry.group), ["general-workspaces-b", "general-workspaces-c"]);
+  assert.deepEqual(entries[0].keys, ["group", "group_label", "shard_index", "shard_count"]);
+  assert.deepEqual(entries[1].keys, ["group", "group_label"], "keys after the matrix must not leak into the last entry");
+});
+
+test("workspaces-c runs the db project alone and workspaces-b no longer carries it", () => {
+  // The db project was 168-250s of the 436-513s workspaces-b vitest time
+  // (PR runs 38084171761, 38083084276 and 38083020834, 2026-10-10), so it
+  // runs in its own lane. The PR and release matrices both carry that lane.
+  const workspacesC = dryRunJson(["--mode", "general", "--group", "general-workspaces-c"]);
+  assert.deepEqual(workspacesC.workspaceProjects, ["@paperclipai/db"]);
+  assert.equal(workspacesC.workspacesVitestShard, null);
+  const workspacesB = dryRunJson(["--mode", "general", "--group", "general-workspaces-b"]);
+  assert.ok(!workspacesB.workspaceProjects.includes("@paperclipai/db"), "db must not run twice");
+  assert.ok(workspacesB.workspaceProjects.length > 0, "workspaces-b must still run its other projects");
+  for (const workflow of ["pr-trusted.yml", "release-verify.yml"]) {
+    const entries = matrixEntries(readFileSync(path.join(repoRoot, ".github", "workflows", workflow), "utf8"));
+    // The parser must demonstrably see shard keys in this workflow, otherwise
+    // the unsharded assertions below could pass for the wrong reason.
+    const sharded = entries.filter(entry => entry.group === "general-workspaces-a");
+    assert.ok(sharded.length > 0 && sharded.every(entry => entry.keys.includes("shard_index") && entry.keys.includes("shard_count")),
+      `${workflow} must carry the sharded workspaces-a entries`);
+    for (const group of ["general-workspaces-b", "general-workspaces-c"]) {
+      const matching = entries.filter(entry => entry.group === group);
+      assert.equal(matching.length, 1, `${workflow} must run ${group} exactly once`);
+      assert.ok(matching[0].keys.includes("group_label"), `${workflow} must label the ${group} job`);
+      assert.deepEqual(matching[0].keys.filter(key => key.startsWith("shard_")), [], `${workflow} must run ${group} unsharded`);
+    }
+  }
+});
+
 test("workspaces-a shards map to Vitest native --shard slices over a stable project list", () => {
   const shards = [0, 1].map((index) =>
     dryRunJson([
diff --git a/scripts/run-vitest-stable.mjs b/scripts/run-vitest-stable.mjs
index dd00f145cda..a62f90094e1 100644
--- a/scripts/run-vitest-stable.mjs
+++ b/scripts/run-vitest-stable.mjs
@@ -117,9 +117,27 @@ function excludedServerSuites(groupName) {
 }
 const generalWorkspacesAGroupName = "general-workspaces-a";
 const generalWorkspacesBGroupName = "general-workspaces-b";
+const generalWorkspacesCGroupName = "general-workspaces-c";
 const generalWorkspacesAProjects = ["@paperclipai/ui", "paperclipai"];
-const generalWorkspacesBProjects = nonServerProjects.filter((project) => !generalWorkspacesAProjects.includes(project));
-const generalGroupNames = [generalServerGroupName, generalWorkspacesAGroupName, generalWorkspacesBGroupName];
+// The db project runs in its own lane. Its vitest invocation took 168-250s
+// of a 436-513s workspaces-b job (PR runs 38084171761, 38083084276 and
+// 38083020834, 2026-10-10), which made workspaces-b the slowest check once
+// the server shards were rebalanced. Vitest's native --shard would not help
+// here: the project is already file-parallel and client.test.ts alone is
+// 117-189s of its wall time, so a hash-ordered slice can land both of its
+// slow suites on one runner. Splitting by project is deterministic and
+// leaves the remaining projects at ~265-275s of vitest time, roughly level
+// with this lane.
+const generalWorkspacesCProjects = ["@paperclipai/db"];
+const generalWorkspacesBProjects = nonServerProjects.filter(
+  (project) => !generalWorkspacesAProjects.includes(project) && !generalWorkspacesCProjects.includes(project),
+);
+const generalGroupNames = [
+  generalServerGroupName,
+  generalWorkspacesAGroupName,
+  generalWorkspacesBGroupName,
+  generalWorkspacesCGroupName,
+];
 const allowedGeneralGroupNames = [
   ...generalGroupNames,
   generalServerWithoutChatGroupName,
@@ -520,6 +538,11 @@ function runGeneralGroup(routeTests, groupName, shardIndex = null, shardCount =
     return;
   }
 
+  if (groupName === generalWorkspacesCGroupName) {
+    runProjectGroup(generalWorkspacesCProjects, groupName);
+    return;
+  }
+
   fail(`Unknown group "${groupName}".`);
 }
 
@@ -604,7 +627,9 @@ if (options.dryRun) {
             ? generalWorkspacesAProjects
             : options.group === generalWorkspacesBGroupName
               ? generalWorkspacesBProjects
-              : null,
+              : options.group === generalWorkspacesCGroupName
+                ? generalWorkspacesCProjects
+                : null,
         workspacesVitestShard:
           options.group === generalWorkspacesAGroupName &&
           options.shardCount !== null &&