feat: add hidden unicode security scan

COMMANDS.md

@@ -26,6 +26,7 @@ fable-agent plinius godmode "improve explanation quality"
 | `session` | Session lifecycle |
 | `skills` | Skill registry ops |
 | `state` | Knowledge state / stats view |
+| `security` | Security scanners |
 | `pai` | PAI/bridge operations |
 | `status` | Runtime surface summary |
 | `workflow` | Load workflow JSON |
@@ -85,6 +86,10 @@ fable-agent plinius godmode "improve explanation quality"
 - `status`
 - Displays command availability, env bootstrap, and runtime wiring summary.
 
+### `security`
+
+- `security scan <target>`
+
 ### `pai`
 
 - `pai status`

src/core/unicode-safety.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { hasHiddenUnicode, stripHiddenUnicode } from "./unicode-safety.js";
+import { findHiddenUnicode, hasHiddenUnicode, stripHiddenUnicode } from "./unicode-safety.js";
 
 describe("unicode safety", () => {
   it("strips hidden instruction carriers", () => {
@@ -8,5 +8,6 @@ describe("unicode safety", () => {
 
     expect(hasHiddenUnicode(text)).toBe(true);
     expect(stripHiddenUnicode(text)).toBe("safetext");
+    expect(findHiddenUnicode(text).map((hit) => hit.codePoint)).toEqual(["U+E0069", "U+200B", "U+202E"]);
   });
 });

src/core/unicode-safety.ts

@@ -9,3 +9,11 @@ export function hasHiddenUnicode(text: string): boolean {
   HIDDEN_UNICODE.lastIndex = 0;
   return HIDDEN_UNICODE.test(text);
 }
+
+export function findHiddenUnicode(text: string): { index: number; codePoint: string }[] {
+  HIDDEN_UNICODE.lastIndex = 0;
+  return [...text.matchAll(HIDDEN_UNICODE)].map((match) => ({
+    index: match.index,
+    codePoint: `U+${match[0].codePointAt(0)!.toString(16).toUpperCase().padStart(4, "0")}`,
+  }));
+}

src/index.ts

@@ -2566,6 +2566,51 @@ plinius
     }
   });
 
+
+// ── Security ────────────────────────────────────────────────
+
+const security = program
+  .command("security")
+  .description("Security scanners");
+
+security
+  .command("scan <target>")
+  .description("Scan files for hidden Unicode prompt-injection carriers")
+  .action(async (target: string) => {
+    const { findHiddenUnicode } = await import("./core/unicode-safety.js");
+    const root = path.resolve(target);
+    const files: string[] = [];
+
+    const walk = (file: string) => {
+      const st = fs.statSync(file);
+      if (st.isDirectory()) {
+        for (const name of fs.readdirSync(file)) {
+          if ([".git", "node_modules", "dist"].includes(name)) continue;
+          walk(path.join(file, name));
+        }
+        return;
+      }
+      if (/\.(md|txt|ts|js|json|yaml|yml)$/i.test(file)) files.push(file);
+    };
+
+    walk(root);
+    let hits = 0;
+    for (const file of files) {
+      const found = findHiddenUnicode(fs.readFileSync(file, "utf-8"));
+      if (found.length === 0) continue;
+      hits += found.length;
+      console.log(`${file}: ${found.map((h) => `${h.codePoint}@${h.index}`).join(", ")}`);
+    }
+
+    if (hits > 0) {
+      console.error(`
+  ✗ Hidden Unicode found: ${hits}`);
+      process.exit(1);
+    }
+    console.log(`
+  ✓ No hidden Unicode found in ${files.length} file(s)`);
+  });
+
 program.parse(process.argv);
 
 // Show help if no args

src/upgrades/familiar-knowledge.ts

@@ -154,7 +154,7 @@ export class FamiliarKnowledge {
       body,
       "",
       processed.contradictions.length > 0
-        ? `> ⚠️ Contradictions: ${processed.contradictions.join("; ")}`
+        ? `> ⚠ Contradictions: ${processed.contradictions.join("; ")}`
         : "",
     ].filter(Boolean).join("\n");