diff --git a/scripts/source.mjs b/scripts/source.mjs
index db4b0d8d3c5..31b617ab26e 100644
--- a/scripts/source.mjs
+++ b/scripts/source.mjs
@@ -24,11 +24,16 @@ export function profileForSlug(slug) {
 }
 
 export function readText(file) {
-  return fs.existsSync(file) ? fs.readFileSync(file, "utf8") : "";
+  const stats = lstatOrMissing(file);
+  if (!stats) return "";
+  assertNotSymlink(file, stats);
+  return fs.readFileSync(file, "utf8");
 }
 
 export function readJson(file, fallback = null) {
-  if (!fs.existsSync(file)) return fallback;
+  const stats = lstatOrMissing(file);
+  if (!stats) return fallback;
+  assertNotSymlink(file, stats);
   try {
     return JSON.parse(fs.readFileSync(file, "utf8"));
   } catch (error) {
@@ -42,21 +47,43 @@ export function writeText(file, text) {
 }
 
 export function markdownFiles(dir) {
-  if (!fs.existsSync(dir)) return [];
-  return fs
-    .readdirSync(dir)
-    .filter((name) => name.endsWith(".md"))
-    .sort()
-    .map((name) => path.join(dir, name));
+  return listedFiles(dir, ".md");
 }
 
 export function jsonFiles(dir) {
-  if (!fs.existsSync(dir)) return [];
-  return fs
-    .readdirSync(dir)
-    .filter((name) => name.endsWith(".json"))
-    .sort()
-    .map((name) => path.join(dir, name));
+  return listedFiles(dir, ".json");
+}
+
+function lstatOrMissing(file) {
+  try {
+    return fs.lstatSync(file);
+  } catch (error) {
+    if (error?.code === "ENOENT") return null;
+    throw error;
+  }
+}
+
+function assertNotSymlink(file, stats) {
+  if (stats.isSymbolicLink()) {
+    throw new Error(`[clawsweeper-state] source contains symlink: ${file}`);
+  }
+}
+
+function listedFiles(dir, suffix) {
+  const dirStats = lstatOrMissing(dir);
+  if (!dirStats) return [];
+  assertNotSymlink(dir, dirStats);
+  const files = [];
+  for (const entry of fs.readdirSync(dir, { withFileTypes: true }).sort((a, b) =>
+    a.name.localeCompare(b.name),
+  )) {
+    const file = path.join(dir, entry.name);
+    if (entry.isSymbolicLink()) {
+      throw new Error(`[clawsweeper-state] source contains symlink: ${file}`);
+    }
+    if (entry.isFile() && entry.name.endsWith(suffix)) files.push(file);
+  }
+  return files;
 }
 
 export function parseFrontMatter(markdown) {
diff --git a/test/source.test.mjs b/test/source.test.mjs
index 209bca9aff3..314ce3c3795 100644
--- a/test/source.test.mjs
+++ b/test/source.test.mjs
@@ -3,7 +3,7 @@ import fs from "node:fs";
 import os from "node:os";
 import path from "node:path";
 import test from "node:test";
-import { readJson } from "../scripts/source.mjs";
+import { jsonFiles, markdownFiles, readJson, readText } from "../scripts/source.mjs";
 
 test("readJson returns null fallback for missing file", () => {
   assert.equal(readJson("/nonexistent/path/does-not-exist.json"), null);
@@ -45,3 +45,52 @@ test("readJson throws on malformed JSON without a fallback", () => {
     fs.rmSync(dir, { recursive: true, force: true });
   }
 });
+
+test("markdownFiles and jsonFiles skip missing directories", () => {
+  const missing = path.join(os.tmpdir(), "clawsweeper-source-missing", "nope");
+  assert.deepEqual(markdownFiles(missing), []);
+  assert.deepEqual(jsonFiles(missing), []);
+});
+
+test("markdownFiles lists regular markdown files", () => {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), "clawsweeper-source-"));
+  try {
+    const file = path.join(dir, "1.md");
+    fs.writeFileSync(file, "ok\n", "utf8");
+    assert.deepEqual(markdownFiles(dir), [file]);
+  } finally {
+    fs.rmSync(dir, { recursive: true, force: true });
+  }
+});
+
+test("source readers reject a symlinked markdown file", () => {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), "clawsweeper-source-"));
+  const external = fs.mkdtempSync(path.join(os.tmpdir(), "clawsweeper-source-ext-"));
+  try {
+    const target = path.join(external, "secret.md");
+    fs.writeFileSync(target, "escaped\n", "utf8");
+    const link = path.join(dir, "1.md");
+    fs.symlinkSync(target, link, "file");
+    assert.throws(() => markdownFiles(dir), /source contains symlink/);
+    assert.throws(() => readText(link), /source contains symlink/);
+  } finally {
+    fs.rmSync(dir, { recursive: true, force: true });
+    fs.rmSync(external, { recursive: true, force: true });
+  }
+});
+
+test("source readers reject a symlinked json file", () => {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), "clawsweeper-source-"));
+  const external = fs.mkdtempSync(path.join(os.tmpdir(), "clawsweeper-source-ext-"));
+  try {
+    const target = path.join(external, "secret.json");
+    fs.writeFileSync(target, '{"escaped":true}\n', "utf8");
+    const link = path.join(dir, "run.json");
+    fs.symlinkSync(target, link, "file");
+    assert.throws(() => jsonFiles(dir), /source contains symlink/);
+    assert.throws(() => readJson(link), /source contains symlink/);
+  } finally {
+    fs.rmSync(dir, { recursive: true, force: true });
+    fs.rmSync(external, { recursive: true, force: true });
+  }
+});