feat(sse): port Claude Code quota-probe bypass + command meta-request helpers (#4083)

Integrated into release/v3.8.28

open-sse/utils/bypassHandler.ts

@@ -69,6 +69,18 @@ export function handleBypassRequest(body, model, userAgent = "") {
     }
   }
 
+  // Pattern 5: Quota probe — max_tokens=1 + "quota" keyword (FCC try_quota_mock).
+  if (!shouldBypass && body.max_tokens === 1) {
+    const userText = messages
+      .filter((m) => m.role === "user")
+      .map((m) => getText(m.content))
+      .join(" ")
+      .toLowerCase();
+    if (userText.includes("quota")) {
+      shouldBypass = true;
+    }
+  }
+
   if (!shouldBypass) return null;
 
   const sourceFormat = detectFormat(body);

open-sse/utils/claudeCodeMetaRequests.ts

@@ -0,0 +1,87 @@
+// Tools whose meaningful prefix is two words (verb + subcommand).
+const TWO_WORD_TOOLS = new Set([
+  "git", "npm", "docker", "kubectl", "cargo", "go", "pip", "yarn", "pnpm", "bun",
+]);
+
+const ENV_ASSIGNMENT_RE = /^[A-Za-z_][A-Za-z0-9_]*=/;
+// Command-injection signals: ; | & ` $(   (newline handled separately)
+const INJECTION_RE = /[;|&`]|\$\(/;
+
+/** Tokenize a shell command on whitespace, respecting simple single/double quotes. */
+function tokenize(command: string): string[] {
+  const tokens: string[] = [];
+  let current = "";
+  let quote: string | null = null;
+  for (const ch of command) {
+    if (quote) {
+      if (ch === quote) quote = null;
+      else current += ch;
+    } else if (ch === '"' || ch === "'") {
+      quote = ch;
+    } else if (/\s/.test(ch)) {
+      if (current) { tokens.push(current); current = ""; }
+    } else {
+      current += ch;
+    }
+  }
+  if (current) tokens.push(current);
+  return tokens;
+}
+
+export function extractCommandPrefix(command: string): string {
+  if (typeof command !== "string" || !command.trim()) return "";
+  if (INJECTION_RE.test(command) || command.includes("\n")) {
+    return "command_injection_detected";
+  }
+  let tokens = tokenize(command);
+  // Strip leading FOO=bar env assignments.
+  while (tokens.length && ENV_ASSIGNMENT_RE.test(tokens[0])) tokens = tokens.slice(1);
+  if (!tokens.length) return "";
+  const head = tokens[0];
+  // Only form a two-word prefix when the second token is an actual subcommand,
+  // not a flag. We intentionally do not parse flag-arguments (e.g. `git -C <path>`);
+  // for those we fall back to the single-word head (conservative, never wrong).
+  if (TWO_WORD_TOOLS.has(head) && tokens.length > 1 && !tokens[1].startsWith("-")) {
+    return `${head} ${tokens[1]}`;
+  }
+  return head;
+}
+
+const READ_COMMANDS = new Set(["cat", "head", "tail", "less", "more", "bat", "type"]);
+const LISTING_COMMANDS = new Set(["ls", "dir", "find", "tree"]);
+// grep flags that consume the NEXT arg (so it is not a filepath).
+const GREP_ARG_FLAGS = new Set(["-e", "-f", "-m", "-A", "-B", "-C"]);
+
+export function extractFilepathsFromCommand(command: string, _output = ""): string[] {
+  if (typeof command !== "string" || !command.trim()) return [];
+  const tokens = tokenize(command);
+  if (!tokens.length) return [];
+  const head = tokens[0];
+
+  if (LISTING_COMMANDS.has(head)) return [];
+
+  if (head === "grep") {
+    const files: string[] = [];
+    let patternConsumed = false;
+    for (let i = 1; i < tokens.length; i++) {
+      const tok = tokens[i];
+      if (tok.startsWith("-")) {
+        if (GREP_ARG_FLAGS.has(tok)) {
+          i++; // skip this flag's argument
+          // -e/-f supply the pattern itself, so the positional pattern is already consumed.
+          if (tok === "-e" || tok === "-f") patternConsumed = true;
+        }
+        continue;
+      }
+      if (!patternConsumed) { patternConsumed = true; continue; } // first non-flag = pattern
+      files.push(tok);
+    }
+    return files;
+  }
+
+  if (READ_COMMANDS.has(head)) {
+    return tokens.slice(1).filter((t) => !t.startsWith("-"));
+  }
+
+  return [];
+}

tests/unit/bypass-handler.test.ts

@@ -83,3 +83,18 @@ test("handleBypassRequest bypasses single-message count probes", async () => {
   assert.equal(payload.usage.total_tokens, 2);
   assert.equal(payload.choices[0].finish_reason, "stop");
 });
+
+test("bypass returns quota response for max_tokens=1 quota probe", () => {
+  const body = {
+    max_tokens: 1,
+    stream: false,
+    messages: [{ role: "user", content: "Please check the quota for this key" }],
+  };
+  const result = handleBypassRequest(body, "x", "claude-cli/2.1.0");
+  assert.ok(result?.success, "should bypass quota probe");
+});
+
+test("bypass does NOT trigger for normal requests", () => {
+  const body = { messages: [{ role: "user", content: "write a function" }] };
+  assert.equal(handleBypassRequest(body, "x", "claude-cli/2.1.0"), null);
+});

tests/unit/claude-code-meta-requests.test.ts

@@ -0,0 +1,53 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { extractCommandPrefix } from "../../open-sse/utils/claudeCodeMetaRequests.ts";
+import { extractFilepathsFromCommand } from "../../open-sse/utils/claudeCodeMetaRequests.ts";
+
+test("extractCommandPrefix returns two-word prefix for known multi-verb tools", () => {
+  assert.equal(extractCommandPrefix("git commit -m 'x'"), "git commit");
+  assert.equal(extractCommandPrefix("npm install lodash"), "npm install");
+  assert.equal(extractCommandPrefix("docker build ."), "docker build");
+});
+
+test("extractCommandPrefix returns single word for simple commands", () => {
+  assert.equal(extractCommandPrefix("ls -la"), "ls");
+  assert.equal(extractCommandPrefix("cat file.txt"), "cat");
+});
+
+test("extractCommandPrefix strips leading env assignments", () => {
+  assert.equal(extractCommandPrefix("FOO=bar npm run build"), "npm run");
+});
+
+test("extractCommandPrefix detects command injection", () => {
+  assert.equal(extractCommandPrefix("ls; rm -rf /"), "command_injection_detected");
+  assert.equal(extractCommandPrefix("echo $(whoami)"), "command_injection_detected");
+  assert.equal(extractCommandPrefix("cat `id`"), "command_injection_detected");
+});
+
+test("extractFilepathsFromCommand returns read files for read commands", () => {
+  assert.deepEqual(extractFilepathsFromCommand("cat src/a.ts src/b.ts", ""), ["src/a.ts", "src/b.ts"]);
+  assert.deepEqual(extractFilepathsFromCommand("head -n5 README.md", ""), ["README.md"]);
+});
+
+test("extractFilepathsFromCommand returns empty for listing commands", () => {
+  assert.deepEqual(extractFilepathsFromCommand("ls -la src/", ""), []);
+  assert.deepEqual(extractFilepathsFromCommand("find . -name '*.ts'", ""), []);
+});
+
+test("extractFilepathsFromCommand skips the grep pattern arg", () => {
+  assert.deepEqual(extractFilepathsFromCommand("grep -n foo src/a.ts", ""), ["src/a.ts"]);
+});
+
+test("extractCommandPrefix stays conservative when a flag precedes the subcommand", () => {
+  // -C takes a path arg; we don't parse flag-args, so fall back to the head
+  // (never emit a wrong two-word prefix like "git -C" or "git /x").
+  assert.equal(extractCommandPrefix("git -C /x commit"), "git");
+});
+
+test("extractFilepathsFromCommand handles grep -e pattern then file", () => {
+  assert.deepEqual(extractFilepathsFromCommand("grep -e pattern a.ts", ""), ["a.ts"]);
+});
+
+test("extractFilepathsFromCommand handles grep -f patternfile then file", () => {
+  assert.deepEqual(extractFilepathsFromCommand("grep -f pats.txt a.ts", ""), ["a.ts"]);
+});