feat(detection): expand error patterns for gRPC, 402/529, and credit errors

Add ratelimit (one word), resource exhausted (Google gRPC RESOURCE_EXHAUSTED),
HTTP 402 (quota_exceeded), HTTP 529 (overloaded), and insufficient credit(s) patterns.
Covers real-world error shapes from Anthropic, OpenAI, and Google providers.

Author: blazejpawlak

src/config/defaults.ts

@@ -4,13 +4,16 @@ import type { PluginConfig } from "../types.js";
 
 export const DEFAULT_PATTERNS = [
   "rate limit",
+  "ratelimit",
   "usage limit",
   "too many requests",
   "quota exceeded",
   "overloaded",
   "capacity exceeded",
   "credits exhausted",
+  "insufficient credit",
   "billing limit",
+  "resource exhausted",
   "429",
 ];
 

src/detection/classifier.ts

@@ -1,14 +1,24 @@
 import type { ErrorCategory } from "../types.js";
 import { matchesAnyPattern } from "./patterns.js";
 
-const RATE_LIMIT_PATTERNS = ["rate limit", "ratelimit", "too many requests", "usage limit", "429"];
+const RATE_LIMIT_PATTERNS = [
+  "rate limit",
+  "ratelimit",
+  "too many requests",
+  "usage limit",
+  "resource exhausted",
+  "resource_exhausted",
+  "429",
+];
 
 const QUOTA_PATTERNS = [
   "quota exceeded",
   "credits exhausted",
   "billing limit",
   "credit limit",
   "insufficient quota",
+  "insufficient credit",
+  "insufficient credits",
   "out of credits",
 ];
 
@@ -38,10 +48,10 @@ export function classifyError(message: string, statusCode?: number): ErrorCatego
   if (statusCode === 429 || matchesAnyPattern(text, RATE_LIMIT_PATTERNS)) {
     return "rate_limit";
   }
-  if (matchesAnyPattern(text, QUOTA_PATTERNS)) {
+  if (statusCode === 402 || matchesAnyPattern(text, QUOTA_PATTERNS)) {
     return "quota_exceeded";
   }
-  if (matchesAnyPattern(text, OVERLOADED_PATTERNS)) {
+  if (statusCode === 529 || matchesAnyPattern(text, OVERLOADED_PATTERNS)) {
     return "overloaded";
   }
   if (matchesAnyPattern(text, TIMEOUT_PATTERNS)) {

test/detection.test.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it } from "bun:test";
 import { classifyError } from "../src/detection/classifier.js";
 import { matchesAnyPattern } from "../src/detection/patterns.js";
+import { DEFAULT_PATTERNS } from "../src/config/defaults.js";
 
 describe("classifyError", () => {
   it("classifies 429 status code as rate_limit", () => {
@@ -45,6 +46,43 @@ describe("classifyError", () => {
     expect(classifyError("RATE LIMIT EXCEEDED")).toBe("rate_limit");
     expect(classifyError("Rate Limit Exceeded")).toBe("rate_limit");
   });
+
+  it("classifies ratelimit (one word) as rate_limit", () => {
+    expect(classifyError("RateLimitError: too fast")).toBe("rate_limit");
+  });
+
+  it("classifies resource exhausted (Google gRPC) as rate_limit", () => {
+    expect(classifyError("resource exhausted")).toBe("rate_limit");
+    expect(classifyError("RESOURCE_EXHAUSTED quota exceeded")).toBe("rate_limit");
+  });
+
+  it("classifies 402 status code as quota_exceeded", () => {
+    expect(classifyError("Payment required", 402)).toBe("quota_exceeded");
+  });
+
+  it("classifies insufficient credit(s) as quota_exceeded", () => {
+    expect(classifyError("insufficient credit balance")).toBe("quota_exceeded");
+    expect(classifyError("Insufficient credits on your account")).toBe("quota_exceeded");
+  });
+
+  it("classifies 529 status code as overloaded (not 5xx)", () => {
+    expect(classifyError("Overloaded", 529)).toBe("overloaded");
+    expect(classifyError("some error", 529)).toBe("overloaded");
+  });
+});
+
+describe("DEFAULT_PATTERNS gate coverage", () => {
+  it("passes ratelimit through the gate", () => {
+    expect(matchesAnyPattern("RateLimitError", DEFAULT_PATTERNS)).toBe(true);
+  });
+
+  it("passes resource exhausted through the gate", () => {
+    expect(matchesAnyPattern("resource exhausted quota", DEFAULT_PATTERNS)).toBe(true);
+  });
+
+  it("passes insufficient credit through the gate", () => {
+    expect(matchesAnyPattern("insufficient credit balance", DEFAULT_PATTERNS)).toBe(true);
+  });
 });
 
 describe("matchesAnyPattern", () => {