fix: clamp tool images to 5MB

src/agents/tool-images.test.ts

@@ -0,0 +1,35 @@
+import sharp from "sharp";
+import { describe, expect, it } from "vitest";
+
+import { sanitizeContentBlocksImages } from "./tool-images.js";
+
+describe("tool image sanitizing", () => {
+  it("shrinks oversized images to <=5MB", async () => {
+    const width = 2800;
+    const height = 2800;
+    const raw = Buffer.alloc(width * height * 3, 0xff);
+    const bigPng = await sharp(raw, {
+      raw: { width, height, channels: 3 },
+    })
+      .png({ compressionLevel: 0 })
+      .toBuffer();
+    expect(bigPng.byteLength).toBeGreaterThan(5 * 1024 * 1024);
+
+    const blocks = [
+      {
+        type: "image" as const,
+        data: bigPng.toString("base64"),
+        mimeType: "image/png",
+      },
+    ];
+
+    const out = await sanitizeContentBlocksImages(blocks, "test");
+    const image = out.find((b) => b.type === "image");
+    if (!image || image.type !== "image") {
+      throw new Error("expected image block");
+    }
+    const size = Buffer.from(image.data, "base64").byteLength;
+    expect(size).toBeLessThanOrEqual(5 * 1024 * 1024);
+    expect(image.mimeType).toBe("image/jpeg");
+  }, 20_000);
+});