fix(cli): strip terminal control characters from API content

Library titles, descriptions, and doc snippets are crowdsourced. Sanitize
them at the API boundary so a malicious entry cannot inject ANSI/OSC
escape sequences into the user's terminal via ctx7 docs or ctx7 library.

Reported by Syed Anas Mohiuddin.

Claude-Session: https://claude.ai/code/session_01XXTv4m4tzcTPQYfa9DvGsv

.changeset/strip-control-chars-cli.md

@@ -0,0 +1,5 @@
+---
+"ctx7": patch
+---
+
+Strip terminal control characters from crowdsourced API content (library titles, descriptions, docs) before printing, preventing ANSI/OSC escape sequence injection in `ctx7 docs` and `ctx7 library` output. Reported by Syed Anas Mohiuddin.

packages/cli/src/__tests__/strip-control-chars.test.ts

@@ -0,0 +1,13 @@
+import { describe, expect, it } from "vitest";
+import { stripControlChars } from "../utils/api.js";
+
+describe("stripControlChars", () => {
+  it("removes escape sequences from nested API content, keeps newlines and tabs", () => {
+    const evil = "\x1b]52;c;ZWNobyBwd25k\x07\x1b[2J\x1b[Htitle\r\n\tok\x9b1m";
+    expect(stripControlChars(evil)).toBe("]52;c;ZWNobyBwd25k[2J[Htitle\n\tok1m");
+    expect(stripControlChars({ a: [evil, 1, null], b: { c: evil } })).toEqual({
+      a: ["]52;c;ZWNobyBwd25k[2J[Htitle\n\tok1m", 1, null],
+      b: { c: "]52;c;ZWNobyBwd25k[2J[Htitle\n\tok1m" },
+    });
+  });
+});

packages/cli/src/utils/api.ts

@@ -16,6 +16,22 @@ import { VERSION } from "../constants.js";
 
 let baseUrl = "https://context7.com";
 
+// Library metadata and docs are crowdsourced. Strip terminal control characters
+// (C0 except \t\n, DEL, C1) so a malicious entry cannot inject escape sequences.
+
+const CONTROL_CHARS = /[\x00-\x08\x0B-\x1F\x7F-\x9F]/g;
+
+export function stripControlChars<T>(value: T): T {
+  if (typeof value === "string") return value.replace(CONTROL_CHARS, "") as T;
+  if (Array.isArray(value)) return value.map(stripControlChars) as T;
+  if (value && typeof value === "object") {
+    return Object.fromEntries(
+      Object.entries(value).map(([k, v]) => [k, stripControlChars(v)])
+    ) as T;
+  }
+  return value;
+}
+
 export function getBaseUrl(): string {
   return baseUrl;
 }
@@ -113,7 +129,7 @@ export async function searchLibraries(
     headers["Authorization"] = `Bearer ${accessToken}`;
   }
   const response = await fetch(`${baseUrl}/api/v2/libs/search?${params}`, { headers });
-  return (await response.json()) as LibrarySearchResponse;
+  return stripControlChars((await response.json()) as LibrarySearchResponse);
 }
 
 export async function getSkillQuota(accessToken: string): Promise<SkillQuotaResponse> {
@@ -306,7 +322,7 @@ export async function resolveLibrary(
     };
   }
 
-  return (await response.json()) as LibrarySearchResponse;
+  return stripControlChars((await response.json()) as LibrarySearchResponse);
 }
 
 export interface GetContextOptions {
@@ -354,8 +370,8 @@ export async function getLibraryContext(
   }
 
   if (options?.type === "txt") {
-    return await response.text();
+    return stripControlChars(await response.text());
   }
 
-  return (await response.json()) as ContextResponse;
+  return stripControlChars((await response.json()) as ContextResponse);
 }