diff --git a/src/memory/batch-error-utils.test.ts b/src/memory/batch-error-utils.test.ts
new file mode 100644
index 00000000000..1f6e7b760b0
--- /dev/null
+++ b/src/memory/batch-error-utils.test.ts
@@ -0,0 +1,26 @@
+import { describe, expect, it } from "vitest";
+import { extractBatchErrorMessage, formatUnavailableBatchError } from "./batch-error-utils.js";
+
+describe("extractBatchErrorMessage", () => {
+  it("returns the first top-level error message", () => {
+    expect(
+      extractBatchErrorMessage([
+        { response: { body: { error: { message: "nested" } } } },
+        { error: { message: "top-level" } },
+      ]),
+    ).toBe("nested");
+  });
+
+  it("falls back to nested response error message", () => {
+    expect(
+      extractBatchErrorMessage([{ response: { body: { error: { message: "nested-only" } } } }, {}]),
+    ).toBe("nested-only");
+  });
+});
+
+describe("formatUnavailableBatchError", () => {
+  it("formats errors and non-error values", () => {
+    expect(formatUnavailableBatchError(new Error("boom"))).toBe("error file unavailable: boom");
+    expect(formatUnavailableBatchError("unreachable")).toBe("error file unavailable: unreachable");
+  });
+});
diff --git a/src/memory/batch-output.test.ts b/src/memory/batch-output.test.ts
new file mode 100644
index 00000000000..b5aa9334238
--- /dev/null
+++ b/src/memory/batch-output.test.ts
@@ -0,0 +1,82 @@
+import { describe, expect, it } from "vitest";
+import { applyEmbeddingBatchOutputLine } from "./batch-output.js";
+
+describe("applyEmbeddingBatchOutputLine", () => {
+  it("stores embedding for successful response", () => {
+    const remaining = new Set(["req-1"]);
+    const errors: string[] = [];
+    const byCustomId = new Map<string, number[]>();
+
+    applyEmbeddingBatchOutputLine({
+      line: {
+        custom_id: "req-1",
+        response: {
+          status_code: 200,
+          body: { data: [{ embedding: [0.1, 0.2] }] },
+        },
+      },
+      remaining,
+      errors,
+      byCustomId,
+    });
+
+    expect(remaining.has("req-1")).toBe(false);
+    expect(errors).toEqual([]);
+    expect(byCustomId.get("req-1")).toEqual([0.1, 0.2]);
+  });
+
+  it("records provider error from line.error", () => {
+    const remaining = new Set(["req-2"]);
+    const errors: string[] = [];
+    const byCustomId = new Map<string, number[]>();
+
+    applyEmbeddingBatchOutputLine({
+      line: {
+        custom_id: "req-2",
+        error: { message: "provider failed" },
+      },
+      remaining,
+      errors,
+      byCustomId,
+    });
+
+    expect(remaining.has("req-2")).toBe(false);
+    expect(errors).toEqual(["req-2: provider failed"]);
+    expect(byCustomId.size).toBe(0);
+  });
+
+  it("records non-2xx response errors and empty embedding errors", () => {
+    const remaining = new Set(["req-3", "req-4"]);
+    const errors: string[] = [];
+    const byCustomId = new Map<string, number[]>();
+
+    applyEmbeddingBatchOutputLine({
+      line: {
+        custom_id: "req-3",
+        response: {
+          status_code: 500,
+          body: { error: { message: "internal" } },
+        },
+      },
+      remaining,
+      errors,
+      byCustomId,
+    });
+
+    applyEmbeddingBatchOutputLine({
+      line: {
+        custom_id: "req-4",
+        response: {
+          status_code: 200,
+          body: { data: [] },
+        },
+      },
+      remaining,
+      errors,
+      byCustomId,
+    });
+
+    expect(errors).toEqual(["req-3: internal", "req-4: empty embedding"]);
+    expect(byCustomId.size).toBe(0);
+  });
+});