co-mono/packages/ai/test/image-limits.test.ts
Mario Zechner 3c9c47d3bb ai: add image limits test suite
Tests provider-specific image limitations across all supported providers:
- Maximum number of images in context
- Maximum image size (bytes)
- Maximum image dimensions

Discovered limits (Dec 2025):
- Anthropic: 100 images, 5MB per image, 8000px max dimension
- OpenAI: 500 images, >=25MB per image
- Gemini: ~2500 images, >=40MB per image
- Mistral: 8 images, ~15MB per image
- OpenRouter: ~40 images (context limited), ~15MB per image
2025-12-16 20:04:34 +01:00

507 lines
17 KiB
TypeScript

/**
* Image limits test suite
*
* Tests provider-specific image limitations:
* - Maximum number of images in a context
* - Maximum image size (bytes)
* - Maximum image dimensions
*
* ============================================================================
* DISCOVERED LIMITS (Dec 2025):
* ============================================================================
*
* | Provider | Model | Max Images | Max Size | Max Dimension |
* |-------------|--------------------|------------|----------|---------------|
* | Anthropic | claude-3-5-haiku | 100 | 5MB | 8000px |
* | OpenAI | gpt-4o-mini | 500 | ≥25MB | (untested) |
* | Gemini | gemini-2.5-flash | ~2500 | ≥40MB | (untested) |
* | Mistral | pixtral-12b | 8 | ~15MB | (untested) |
* | OpenRouter | z-ai/glm-4.5v | ~40* | ~15MB | (untested) |
*
* Notes:
* - Anthropic: Also has a "many images" rule where >20 images reduces max
* dimension to 2000px. Total request size capped at 32MB.
* - OpenAI: Documented limit is 20MB, but we observed ≥25MB working.
* - OpenRouter: * Limited by context window (65k tokens), not explicit image limit.
* - Gemini: Very permissive, hits internal errors around 2500-3000 images.
* - Mistral: Very restrictive on image count (only 8 images allowed).
*
* ============================================================================
*/
import { execSync } from "node:child_process";
import { mkdirSync, rmSync } from "node:fs";
import { dirname, join } from "node:path";
import { fileURLToPath } from "node:url";
import { afterAll, beforeAll, describe, expect, it } from "vitest";
import { getModel } from "../src/models.js";
import { complete } from "../src/stream.js";
import type { Api, Context, ImageContent, Model, OptionsForApi, UserMessage } from "../src/types.js";
const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);
// Temp directory for generated images
const TEMP_DIR = join(__dirname, ".temp-images");
/**
* Generate a valid PNG image of specified dimensions using ImageMagick
*/
function generateImage(width: number, height: number, filename: string): string {
const filepath = join(TEMP_DIR, filename);
execSync(`magick -size ${width}x${height} xc:red "${filepath}"`, { stdio: "ignore" });
const buffer = require("fs").readFileSync(filepath);
return buffer.toString("base64");
}
/**
* Generate a valid PNG image of approximately the specified size in bytes
*/
function generateImageWithSize(targetBytes: number, filename: string): string {
const filepath = join(TEMP_DIR, filename);
// Use uncompressed PNG to get predictable sizes
// Each pixel is 3 bytes (RGB), plus PNG overhead (~100 bytes)
// For a square image: side = sqrt(targetBytes / 3)
const side = Math.ceil(Math.sqrt(targetBytes / 3));
// Use noise pattern to prevent compression from shrinking the file
execSync(`magick -size ${side}x${side} xc: +noise Random -depth 8 PNG24:"${filepath}"`, { stdio: "ignore" });
// Check actual size and adjust if needed
const stats = require("fs").statSync(filepath);
if (stats.size < targetBytes * 0.8) {
// If too small, increase dimensions
const newSide = Math.ceil(side * Math.sqrt(targetBytes / stats.size));
execSync(`magick -size ${newSide}x${newSide} xc: +noise Random -depth 8 PNG24:"${filepath}"`, {
stdio: "ignore",
});
}
const buffer = require("fs").readFileSync(filepath);
return buffer.toString("base64");
}
/**
* Create a user message with multiple images
*/
function createMultiImageMessage(imageCount: number, imageBase64: string): UserMessage {
const content: (ImageContent | { type: "text"; text: string })[] = [
{ type: "text", text: `I am sending you ${imageCount} images. Just reply with "received ${imageCount}".` },
];
for (let i = 0; i < imageCount; i++) {
content.push({
type: "image",
data: imageBase64,
mimeType: "image/png",
});
}
return {
role: "user",
content,
timestamp: Date.now(),
};
}
/**
* Test sending a specific number of images to a model
*/
async function testImageCount<TApi extends Api>(
model: Model<TApi>,
imageCount: number,
imageBase64: string,
options?: OptionsForApi<TApi>,
): Promise<{ success: boolean; error?: string }> {
const context: Context = {
messages: [createMultiImageMessage(imageCount, imageBase64)],
};
try {
const response = await complete(model, context, options);
if (response.stopReason === "error") {
return { success: false, error: response.errorMessage };
}
return { success: true };
} catch (e) {
return { success: false, error: e instanceof Error ? e.message : String(e) };
}
}
/**
* Test sending an image of a specific size
*/
async function testImageSize<TApi extends Api>(
model: Model<TApi>,
imageBase64: string,
options?: OptionsForApi<TApi>,
): Promise<{ success: boolean; error?: string }> {
const context: Context = {
messages: [
{
role: "user",
content: [
{ type: "text", text: "I am sending you an image. Just reply with 'received'." },
{ type: "image", data: imageBase64, mimeType: "image/png" },
],
timestamp: Date.now(),
},
],
};
try {
const response = await complete(model, context, options);
if (response.stopReason === "error") {
return { success: false, error: response.errorMessage };
}
return { success: true };
} catch (e) {
return { success: false, error: e instanceof Error ? e.message : String(e) };
}
}
/**
* Test sending an image with specific dimensions
*/
async function testImageDimensions<TApi extends Api>(
model: Model<TApi>,
imageBase64: string,
options?: OptionsForApi<TApi>,
): Promise<{ success: boolean; error?: string }> {
const context: Context = {
messages: [
{
role: "user",
content: [
{ type: "text", text: "I am sending you an image. Just reply with 'received'." },
{ type: "image", data: imageBase64, mimeType: "image/png" },
],
timestamp: Date.now(),
},
],
};
try {
const response = await complete(model, context, options);
if (response.stopReason === "error") {
return { success: false, error: response.errorMessage };
}
return { success: true };
} catch (e) {
return { success: false, error: e instanceof Error ? e.message : String(e) };
}
}
/**
* Find the maximum value that succeeds using linear search
*/
async function findLimit(
testFn: (value: number) => Promise<{ success: boolean; error?: string }>,
min: number,
max: number,
step: number,
): Promise<{ limit: number; lastError?: string }> {
let lastSuccess = min;
let lastError: string | undefined;
for (let value = min; value <= max; value += step) {
console.log(` Testing value: ${value}...`);
const result = await testFn(value);
if (result.success) {
lastSuccess = value;
console.log(` SUCCESS`);
} else {
lastError = result.error;
console.log(` FAILED: ${result.error?.substring(0, 100)}`);
break;
}
}
return { limit: lastSuccess, lastError };
}
// =============================================================================
// Provider-specific test suites
// =============================================================================
describe("Image Limits E2E Tests", () => {
let smallImage: string; // 100x100 for count tests
beforeAll(() => {
// Create temp directory
mkdirSync(TEMP_DIR, { recursive: true });
// Generate small test image for count tests
smallImage = generateImage(100, 100, "small.png");
});
afterAll(() => {
// Clean up temp directory
rmSync(TEMP_DIR, { recursive: true, force: true });
});
// -------------------------------------------------------------------------
// Anthropic (claude-3-5-haiku-20241022)
// Limits: 100 images, 5MB per image, 8000px max dimension
// -------------------------------------------------------------------------
describe.skipIf(!process.env.ANTHROPIC_API_KEY)("Anthropic (claude-3-5-haiku-20241022)", () => {
const model = getModel("anthropic", "claude-3-5-haiku-20241022");
it("should accept a small number of images (5)", async () => {
const result = await testImageCount(model, 5, smallImage);
expect(result.success, result.error).toBe(true);
});
it("should find maximum image count limit", { timeout: 600000 }, async () => {
// Known limit: 100 images
const { limit, lastError } = await findLimit((count) => testImageCount(model, count, smallImage), 20, 120, 20);
console.log(`\n Anthropic max images: ~${limit} (last error: ${lastError})`);
expect(limit).toBeGreaterThanOrEqual(80);
expect(limit).toBeLessThanOrEqual(100);
});
it("should find maximum image size limit", { timeout: 600000 }, async () => {
const MB = 1024 * 1024;
// Known limit: 5MB per image
const sizes = [1, 2, 3, 4, 5, 6];
let lastSuccess = 0;
let lastError: string | undefined;
for (const sizeMB of sizes) {
console.log(` Testing size: ${sizeMB}MB...`);
const imageBase64 = generateImageWithSize(sizeMB * MB, `size-${sizeMB}mb.png`);
const result = await testImageSize(model, imageBase64);
if (result.success) {
lastSuccess = sizeMB;
console.log(` SUCCESS`);
} else {
lastError = result.error;
console.log(` FAILED: ${result.error?.substring(0, 100)}`);
break;
}
}
console.log(`\n Anthropic max image size: ~${lastSuccess}MB (last error: ${lastError})`);
expect(lastSuccess).toBeGreaterThanOrEqual(1);
});
it("should find maximum image dimension limit", { timeout: 600000 }, async () => {
// Known limit: 8000px
const dimensions = [1000, 2000, 4000, 6000, 8000, 10000];
let lastSuccess = 0;
let lastError: string | undefined;
for (const dim of dimensions) {
console.log(` Testing dimension: ${dim}x${dim}...`);
const imageBase64 = generateImage(dim, dim, `dim-${dim}.png`);
const result = await testImageDimensions(model, imageBase64);
if (result.success) {
lastSuccess = dim;
console.log(` SUCCESS`);
} else {
lastError = result.error;
console.log(` FAILED: ${result.error?.substring(0, 100)}`);
break;
}
}
console.log(`\n Anthropic max dimension: ~${lastSuccess}px (last error: ${lastError})`);
expect(lastSuccess).toBeGreaterThanOrEqual(6000);
expect(lastSuccess).toBeLessThanOrEqual(8000);
});
});
// -------------------------------------------------------------------------
// OpenAI (gpt-4o-mini via openai-completions)
// Limits: 500 images, ~20MB per image (documented)
// -------------------------------------------------------------------------
describe.skipIf(!process.env.OPENAI_API_KEY)("OpenAI (gpt-4o-mini)", () => {
const model: Model<"openai-completions"> = { ...getModel("openai", "gpt-4o-mini"), api: "openai-completions" };
it("should accept a small number of images (5)", async () => {
const result = await testImageCount(model, 5, smallImage);
expect(result.success, result.error).toBe(true);
});
it("should find maximum image count limit", { timeout: 600000 }, async () => {
// Known limit: 500 images
const { limit, lastError } = await findLimit(
(count) => testImageCount(model, count, smallImage),
100,
600,
100,
);
console.log(`\n OpenAI max images: ~${limit} (last error: ${lastError})`);
expect(limit).toBeGreaterThanOrEqual(400);
expect(limit).toBeLessThanOrEqual(500);
});
it("should find maximum image size limit", { timeout: 600000 }, async () => {
const MB = 1024 * 1024;
// Documented limit: 20MB
const sizes = [5, 10, 15, 20, 25];
let lastSuccess = 0;
let lastError: string | undefined;
for (const sizeMB of sizes) {
console.log(` Testing size: ${sizeMB}MB...`);
const imageBase64 = generateImageWithSize(sizeMB * MB, `size-${sizeMB}mb.png`);
const result = await testImageSize(model, imageBase64);
if (result.success) {
lastSuccess = sizeMB;
console.log(` SUCCESS`);
} else {
lastError = result.error;
console.log(` FAILED: ${result.error?.substring(0, 100)}`);
break;
}
}
console.log(`\n OpenAI max image size: ~${lastSuccess}MB (last error: ${lastError})`);
expect(lastSuccess).toBeGreaterThanOrEqual(15);
});
});
// -------------------------------------------------------------------------
// Google Gemini (gemini-2.5-flash)
// Limits: Very high (~2500 images), large size support
// -------------------------------------------------------------------------
describe.skipIf(!process.env.GEMINI_API_KEY)("Gemini (gemini-2.5-flash)", () => {
const model = getModel("google", "gemini-2.5-flash");
it("should accept a small number of images (5)", async () => {
const result = await testImageCount(model, 5, smallImage);
expect(result.success, result.error).toBe(true);
});
it("should find maximum image count limit", { timeout: 900000 }, async () => {
// Known to work up to ~2500, hits errors around 3000
const { limit, lastError } = await findLimit(
(count) => testImageCount(model, count, smallImage),
500,
3000,
500,
);
console.log(`\n Gemini max images: ~${limit} (last error: ${lastError})`);
expect(limit).toBeGreaterThanOrEqual(500);
});
it("should find maximum image size limit", { timeout: 600000 }, async () => {
const MB = 1024 * 1024;
// Very permissive, tested up to 60MB successfully
const sizes = [10, 20, 30, 40];
let lastSuccess = 0;
let lastError: string | undefined;
for (const sizeMB of sizes) {
console.log(` Testing size: ${sizeMB}MB...`);
const imageBase64 = generateImageWithSize(sizeMB * MB, `size-${sizeMB}mb.png`);
const result = await testImageSize(model, imageBase64);
if (result.success) {
lastSuccess = sizeMB;
console.log(` SUCCESS`);
} else {
lastError = result.error;
console.log(` FAILED: ${result.error?.substring(0, 100)}`);
break;
}
}
console.log(`\n Gemini max image size: ~${lastSuccess}MB (last error: ${lastError})`);
expect(lastSuccess).toBeGreaterThanOrEqual(20);
});
});
// -------------------------------------------------------------------------
// Mistral (pixtral-12b)
// Limits: ~8 images, ~15MB per image
// -------------------------------------------------------------------------
describe.skipIf(!process.env.MISTRAL_API_KEY)("Mistral (pixtral-12b)", () => {
const model = getModel("mistral", "pixtral-12b");
it("should accept a small number of images (5)", async () => {
const result = await testImageCount(model, 5, smallImage);
expect(result.success, result.error).toBe(true);
});
it("should find maximum image count limit", { timeout: 600000 }, async () => {
// Known to fail around 9 images
const { limit, lastError } = await findLimit((count) => testImageCount(model, count, smallImage), 5, 15, 1);
console.log(`\n Mistral max images: ~${limit} (last error: ${lastError})`);
expect(limit).toBeGreaterThanOrEqual(5);
});
it("should find maximum image size limit", { timeout: 600000 }, async () => {
const MB = 1024 * 1024;
const sizes = [5, 10, 15, 20];
let lastSuccess = 0;
let lastError: string | undefined;
for (const sizeMB of sizes) {
console.log(` Testing size: ${sizeMB}MB...`);
const imageBase64 = generateImageWithSize(sizeMB * MB, `size-${sizeMB}mb.png`);
const result = await testImageSize(model, imageBase64);
if (result.success) {
lastSuccess = sizeMB;
console.log(` SUCCESS`);
} else {
lastError = result.error;
console.log(` FAILED: ${result.error?.substring(0, 100)}`);
break;
}
}
console.log(`\n Mistral max image size: ~${lastSuccess}MB (last error: ${lastError})`);
expect(lastSuccess).toBeGreaterThanOrEqual(5);
});
});
// -------------------------------------------------------------------------
// OpenRouter (z-ai/glm-4.5v)
// Limits: Context-window limited (~45 images at 100x100), ~15MB per image
// -------------------------------------------------------------------------
describe.skipIf(!process.env.OPENROUTER_API_KEY)("OpenRouter (z-ai/glm-4.5v)", () => {
const model = getModel("openrouter", "z-ai/glm-4.5v");
it("should accept a small number of images (5)", async () => {
const result = await testImageCount(model, 5, smallImage);
expect(result.success, result.error).toBe(true);
});
it("should find maximum image count limit", { timeout: 600000 }, async () => {
// Limited by context window, not explicit image limit
const { limit, lastError } = await findLimit((count) => testImageCount(model, count, smallImage), 10, 60, 10);
console.log(`\n OpenRouter max images: ~${limit} (last error: ${lastError})`);
expect(limit).toBeGreaterThanOrEqual(10);
});
it("should find maximum image size limit", { timeout: 600000 }, async () => {
const MB = 1024 * 1024;
const sizes = [5, 10, 15, 20];
let lastSuccess = 0;
let lastError: string | undefined;
for (const sizeMB of sizes) {
console.log(` Testing size: ${sizeMB}MB...`);
const imageBase64 = generateImageWithSize(sizeMB * MB, `size-${sizeMB}mb.png`);
const result = await testImageSize(model, imageBase64);
if (result.success) {
lastSuccess = sizeMB;
console.log(` SUCCESS`);
} else {
lastError = result.error;
console.log(` FAILED: ${result.error?.substring(0, 100)}`);
break;
}
}
console.log(`\n OpenRouter max image size: ~${lastSuccess}MB (last error: ${lastError})`);
expect(lastSuccess).toBeGreaterThanOrEqual(5);
});
});
});