import { describe, expect, it } from "vitest";
import type { AssistantMessage } from "../src/types.js";
import { isContextOverflow } from "../src/utils/overflow.js";
function createErrorMessage(errorMessage: string): AssistantMessage {
return {
role: "assistant",
content: [],
api: "openai-completions",
provider: "ollama",
model: "qwen3.5:35b",
usage: {
input: 0,
output: 0,
cacheRead: 0,
cacheWrite: 0,
totalTokens: 0,
cost: {
input: 0,
output: 0,
cacheRead: 0,
cacheWrite: 0,
total: 0,
},
},
stopReason: "error",
errorMessage,
timestamp: Date.now(),
};
}
describe("isContextOverflow", () => {
const litellmError =
"400 litellm.BadRequestError: OpenAIException - Requested token count exceeds the model's maximum context length of 262144 tokens. You requested a total of 270128 tokens: 261936 tokens from the input messages and 8192 tokens for the completion. Please reduce the number of tokens in the input messages or the completion to fit within the limit.. Received Model Group=qwen3.8-27b-nvfp4";
it.each([262144, undefined])("detects LiteLLM context rejection with contextWindow=%s", (contextWindow) => {
expect(isContextOverflow(createErrorMessage(litellmError), contextWindow)).toBe(true);
});
it("detects context rejection without a proxy prefix, regardless of case", () => {
const message = createErrorMessage(
"REQUESTED TOKEN COUNT EXCEEDS THE MODEL'S MAXIMUM CONTEXT LENGTH OF 262144 TOKENS.",
);
expect(isContextOverflow(message)).toBe(true);
});
it.each([
"429 rate limit: too many tokens",
"Requested token count exceeds the per-minute token quota.",
"400 litellm.BadRequestError: unsupported parameter: temperature",
`429 rate limit: upstream previously returned ${litellmError}`,
])("does not classify an unrelated or rate-limited rejection as overflow: %s", (errorMessage) => {
expect(isContextOverflow(createErrorMessage(errorMessage), 262144)).toBe(false);
});
it.each(["stop", "aborted"] as const)("ignores context error text with stopReason=%s", (stopReason) => {
expect(isContextOverflow({ ...createErrorMessage(litellmError), stopReason }, 262144)).toBe(false);
});
it("detects explicit Ollama prompt-too-long errors", () => {
const message = createErrorMessage("400 `prompt too long; exceeded max context length by 100918 tokens`");
expect(isContextOverflow(message, 32768)).toBe(true);
});
it("does not treat generic non-overflow Ollama errors as overflow", () => {
const message = createErrorMessage("500 `model runner crashed unexpectedly`");
expect(isContextOverflow(message, 32768)).toBe(false);
});
it("does not treat Bedrock throttling 'Too many tokens' as overflow", () => {
const message = createErrorMessage("Throttling error: Too many tokens, please wait before trying again.");
expect(isContextOverflow(message, 200000)).toBe(false);
});
it("does not treat Bedrock service unavailable as overflow", () => {
const message = createErrorMessage("Service unavailable: The service is temporarily unavailable.");
expect(isContextOverflow(message, 200000)).toBe(false);
});
it("does not treat generic rate limit errors as overflow", () => {
const message = createErrorMessage("Rate limit exceeded, please retry after 30 seconds.");
expect(isContextOverflow(message, 200000)).toBe(false);
});
it("does not treat HTTP 429 style errors as overflow", () => {
const message = createErrorMessage("Too many requests. Please slow down.");
expect(isContextOverflow(message, 200000)).toBe(false);
});
function createLengthStopMessage(input: number, cacheRead: number, output: number): AssistantMessage {
return {
role: "assistant",
content: [],
api: "openai-completions",
provider: "xiaomi",
model: "mimo-v2.5-pro",
usage: {
input,
output,
cacheRead,
cacheWrite: 0,
totalTokens: input + cacheRead + output,
cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
},
stopReason: "length",
timestamp: Date.now(),
};
}
it("detects Xiaomi-style overflow (length stop with zero output and filled context)", () => {
const message = createLengthStopMessage(58, 1048512, 0);
expect(isContextOverflow(message, 1048576)).toBe(true);
});
it("does not treat normal length stops with output as overflow", () => {
const message = createLengthStopMessage(1000, 0, 4096);
expect(isContextOverflow(message, 200000)).toBe(false);
});
it("does not treat length stops far below context as overflow", () => {
const message = createLengthStopMessage(100, 0, 0);
expect(isContextOverflow(message, 200000)).toBe(false);
});
});