diff --git a/src/indexer/index.ts b/src/indexer/index.ts
index 136045b..990f764 100644
--- a/src/indexer/index.ts
+++ b/src/indexer/index.ts
@@ -3816,7 +3816,22 @@ export class Indexer {
 
     for (const file of files) {
       const storedPath = this.toStoredFilePath(file.path);
-      const currentHash = hashFile(file.path);
+      let currentHash: string;
+      try {
+        currentHash = hashFile(file.path);
+      } catch (error) {
+        // A file that is unreadable at the OS level (e.g., an LSM denial that
+        // returns EPERM despite readable mode bits, or a permissions error)
+        // must not abort the whole index. The hash step opens the file; a bare
+        // throw here previously tore down the entire run. Skip the file and
+        // continue so the remaining files index.
+        stats.skippedFiles.push({ path: this.toCanonicalFilePath(file.path), reason: "unreadable" });
+        this.logger.warn("Skipped unreadable file during indexing", {
+          path: file.path,
+          error: getErrorMessage(error),
+        });
+        continue;
+      }
       currentFileHashes.set(storedPath, currentHash);
 
       const cachedHashMatches = this.fileHashCache.get(storedPath) === currentHash;
@@ -5071,7 +5086,20 @@ export class Indexer {
     );
     const currentFileHashes = new Map<string, string>();
     for (const file of files) {
-      currentFileHashes.set(this.toStoredFilePath(file.path), hashFile(file.path));
+      let hash: string;
+      try {
+        hash = hashFile(file.path);
+      } catch (error) {
+        // An unreadable file (OS-level EPERM/EACCES) makes freshness unknowable;
+        // treat the index as not-current so the next index_codebase run rebuilds
+        // (which skips unreadable files) instead of aborting here.
+        this.logger.warn("Skipped unreadable file during freshness check", {
+          path: file.path,
+          error: getErrorMessage(error),
+        });
+        return { readable: false, current: false, reason: "unreadable" };
+      }
+      currentFileHashes.set(this.toStoredFilePath(file.path), hash);
     }
 
     const scopedRoots = this.config.scope === "global" ? this.getScopedRoots() : null;
diff --git a/src/utils/files.ts b/src/utils/files.ts
index c925227..c8583c9 100644
--- a/src/utils/files.ts
+++ b/src/utils/files.ts
@@ -31,7 +31,7 @@ export function hasProjectMarker(projectRoot: string): boolean {
 
 export interface SkippedFile {
   path: string;
-  reason: "too_large" | "excluded" | "gitignore" | "no_match";
+  reason: "too_large" | "excluded" | "gitignore" | "no_match" | "unreadable";
 }
 
 export interface CollectFilesResult {
diff --git a/tests/skip-unreadable-file.test.ts b/tests/skip-unreadable-file.test.ts
new file mode 100644
index 0000000..29e932c
--- /dev/null
+++ b/tests/skip-unreadable-file.test.ts
@@ -0,0 +1,121 @@
+import * as fs from "fs";
+import * as os from "os";
+import * as path from "path";
+
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+import { parseConfig } from "../src/config/schema.js";
+import { Indexer } from "../src/indexer/index.js";
+
+// A file that is unreadable at the OS level (chmod 000 -> open() returns EACCES;
+// an LSM denial returns EPERM) must be skipped, not abort the whole index. The
+// hash step (native/src/hasher.rs fs::File::open) throws on such a file; the
+// indexer wraps hashFile in try/catch and records the file with reason
+// "unreadable" so the remaining files index. chmod 000 exercises the same catch
+// path as an EPERM-by-LSM file (e.g. Matlab2's lib/@medusa7/calc_spreads.m).
+describe("indexer skips unreadable files instead of aborting", () => {
+  let tempDir: string;
+  let tempHome: string;
+  let fetchSpy: ReturnType<typeof vi.spyOn>;
+  const embeddingDimensions = 8;
+  let _indexers: Indexer[] = [];
+
+  beforeEach(() => {
+    fetchSpy = vi.spyOn(globalThis, "fetch");
+    fetchSpy.mockImplementation(async (_url: Parameters<typeof fetch>[0], init?: Parameters<typeof fetch>[1]) => {
+      const body = JSON.parse(String(init?.body ?? "{}")) as { input?: string[] };
+      const texts = Array.isArray(body.input) ? body.input : [];
+      const data = texts.map((text) => {
+        let seed = 0;
+        for (const ch of text) {
+          seed = (seed * 31 + ch.charCodeAt(0)) % 1000;
+        }
+        return {
+          embedding: Array.from(
+            { length: embeddingDimensions },
+            (_, idx) => ((seed + idx * 17) % 997) / 997,
+          ),
+        };
+      });
+      return new Response(
+        JSON.stringify({ data, usage: { total_tokens: Math.max(1, texts.length * embeddingDimensions) } }),
+        { status: 200 },
+      );
+    });
+
+    tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "skip-unreadable-"));
+    tempHome = fs.mkdtempSync(path.join(os.tmpdir(), "skip-unreadable-home-"));
+    fs.mkdirSync(path.join(tempDir, "src"), { recursive: true });
+    // A readable source file that should index normally.
+    fs.writeFileSync(
+      path.join(tempDir, "src", "readable.ts"),
+      ["export function alpha() {", "  return 'alpha';", "}", ""].join("\n"),
+      "utf-8",
+    );
+    // An unreadable source file (chmod 000): passes the walk (stat is allowed for
+    // the owner) but open() in hashFile fails. The indexer must skip it.
+    fs.writeFileSync(
+      path.join(tempDir, "src", "unreadable.ts"),
+      ["export function beta() {", "  return 'beta';", "}", ""].join("\n"),
+      "utf-8",
+    );
+    fs.chmodSync(path.join(tempDir, "src", "unreadable.ts"), 0o000);
+  });
+
+  afterEach(async () => {
+    await Promise.all(_indexers.map((i) => i.close()));
+    _indexers = [];
+    fetchSpy.mockRestore();
+    // Restore perms so cleanup is robust, then remove.
+    try {
+      fs.chmodSync(path.join(tempDir, "src", "unreadable.ts"), 0o644);
+    } catch {
+      // file may be gone
+    }
+    fs.rmSync(tempDir, { recursive: true, force: true });
+    fs.rmSync(tempHome, { recursive: true, force: true });
+  });
+
+  function createIndexer(projectRoot: string): Indexer {
+    const config = parseConfig({
+      embeddingProvider: "custom",
+      customProvider: {
+        baseUrl: "http://localhost:11434/v1",
+        model: `mock-${embeddingDimensions}d`,
+        dimensions: embeddingDimensions,
+      },
+      debug: { enabled: true, logLevel: "warn", logSearch: false, logEmbedding: false, logCache: false, logGc: false, logBranch: false, metrics: false },
+      indexing: { watchFiles: false, retries: 0, retryDelayMs: 1 },
+    });
+    const indexer = new Indexer(projectRoot, config, "opencode");
+    _indexers.push(indexer);
+    return indexer;
+  }
+
+  it("indexes the readable file and records the unreadable file as skipped", async () => {
+    const indexer = createIndexer(tempDir);
+    const stats = await indexer.index();
+
+    expect(stats.failedChunks).toBe(0);
+    expect(stats.indexedChunks).toBeGreaterThan(0);
+    const unreadableSkip = stats.skippedFiles.find(
+      (entry) => entry.reason === "unreadable" && entry.path.endsWith("unreadable.ts"),
+    );
+    expect(unreadableSkip).toBeDefined();
+  });
+
+  // The same unreadable-file throw also runs through getIndexFreshness, which
+  // hashes every collected file to compare against the cached hashes. Before
+  // the guard, a single unreadable file rejected the freshness promise and
+  // aborted the check; the guard returns reason "unreadable" instead. The
+  // index must exist first, or getIndexFreshness returns "missing" before it
+  // reaches the hash loop, so index once, then check freshness.
+  it("reports the index as unreadable during the freshness check", async () => {
+    const indexer = createIndexer(tempDir);
+    await indexer.index();
+
+    const freshness = await indexer.getIndexFreshness();
+
+    expect(freshness).toEqual({ readable: false, current: false, reason: "unreadable" });
+  });
+});
\ No newline at end of file