diff --git a/src/core/tool_executor.ts b/src/core/tool_executor.ts
index b90a19c..65d4824 100644
--- a/src/core/tool_executor.ts
+++ b/src/core/tool_executor.ts
@@ -7,13 +7,15 @@
 // regardless of which side originally ran it.
 
 import { spawnSync } from "node:child_process";
-import { existsSync, mkdirSync, readFileSync, realpathSync, statSync, writeFileSync } from "node:fs";
-import { dirname, resolve, sep } from "node:path";
+import { existsSync, mkdirSync, readdirSync, readFileSync, realpathSync, statSync, writeFileSync } from "node:fs";
+import { dirname, relative, resolve, sep } from "node:path";
 import type { ToolName } from "./brain_protocol.js";
 import { webFetch, webSearch } from "./web.js";
 
 const MAX_OUTPUT = 8000;
 const DEFAULT_TEST_CMD = "pytest -q";
+const SEARCH_MAX_HITS = 40;
+const SEARCH_SKIP_DIRS = new Set([".git", "node_modules", "dist"]);
 
 export interface ToolResult {
   output: string;
@@ -68,6 +70,11 @@ export class ToolExecutor {
     if (r.error && (r.error as NodeJS.ErrnoException).code === "ETIMEDOUT") {
       return { output: `[timeout after ${Math.round(timeoutMs / 1000)}s]`, exitCode: 124 };
     }
+    if (r.error) {
+      const err = r.error as NodeJS.ErrnoException;
+      const code = err.code ?? "UNKNOWN";
+      return { output: `[spawn error ${code}: ${err.message}]`, exitCode: code === "ENOENT" ? 127 : 1 };
+    }
     const code = r.status ?? 1;
     const body = capHeadTail((r.stdout ?? "") + (r.stderr ?? ""), MAX_OUTPUT);
     return { output: `[exit ${code}]\n${body}`, exitCode: code };
@@ -145,9 +152,37 @@ export class ToolExecutor {
   }
 
   private repoSearch(query: string): ToolResult {
-    // grep across the tree (ripgrep-free for portability); cap to 40 hits.
-    const q = JSON.stringify(query);
-    return this.run(`grep -rIn -- ${q} . | head -40`);
+    if (!query) return { output: "[exit 0]\n", exitCode: 0 };
+
+    const hits: string[] = [];
+    const visit = (dir: string): void => {
+      if (hits.length >= SEARCH_MAX_HITS) return;
+      for (const ent of readdirSync(dir, { withFileTypes: true })) {
+        if (hits.length >= SEARCH_MAX_HITS) return;
+        if (ent.isSymbolicLink()) continue;
+        if (ent.isDirectory()) {
+          if (SEARCH_SKIP_DIRS.has(ent.name)) continue;
+          const child = resolve(dir, ent.name);
+          const real = realpathSync(child);
+          if (real === this.root || real.startsWith(this.root + sep)) visit(child);
+          continue;
+        }
+        if (!ent.isFile()) continue;
+
+        const file = resolve(dir, ent.name);
+        const buf = readFileSync(file);
+        if (buf.includes(0)) continue;
+        const rel = "./" + relative(this.root, file).split(sep).join("/");
+        const lines = buf.toString("utf8").replace(/\r\n/g, "\n").replace(/\r/g, "\n").split("\n");
+        for (let i = 0; i < lines.length && hits.length < SEARCH_MAX_HITS; i++) {
+          const line = lines[i]!;
+          if (line.includes(query)) hits.push(rel + ":" + (i + 1) + ":" + line);
+        }
+      }
+    };
+
+    visit(this.root);
+    return { output: "[exit 0]\n" + capHeadTail(hits.join("\n"), MAX_OUTPUT), exitCode: 0 };
   }
 
   private gitCommit(message: string): ToolResult {
diff --git a/test/bridge.test.ts b/test/bridge.test.ts
index 978dd16..d36d967 100644
--- a/test/bridge.test.ts
+++ b/test/bridge.test.ts
@@ -1,6 +1,6 @@
 import { test } from "node:test";
 import assert from "node:assert/strict";
-import { mkdtempSync, readFileSync, rmSync, symlinkSync, mkdirSync, existsSync } from "node:fs";
+import { mkdtempSync, readFileSync, rmSync, symlinkSync, mkdirSync, existsSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
@@ -128,6 +128,44 @@ test("ToolExecutor refuses a path escaping the workspace", () => {
   }
 });
 
+test("repo_search finds literal matches recursively without external grep", () => {
+  const dir = mkdtempSync(join(tmpdir(), "aether-search-"));
+  try {
+    mkdirSync(join(dir, "sub"));
+    mkdirSync(join(dir, "node_modules"));
+    writeFileSync(join(dir, "a.txt"), "needle one\nnope\nneedle two\n", "utf8");
+    writeFileSync(join(dir, "sub", "b.txt"), "nested needle\n", "utf8");
+    writeFileSync(join(dir, "node_modules", "ignored.txt"), "needle ignored\n", "utf8");
+    writeFileSync(join(dir, "binary.bin"), Buffer.from([0, 110, 101, 101, 100, 108, 101]));
+
+    const r = new ToolExecutor(dir).execute("repo_search", { query: "needle" });
+
+    assert.equal(r.exitCode, 0);
+    assert.match(r.output, /^\[exit 0\]\n/);
+    assert.match(r.output, /\.\/a\.txt:1:needle one/);
+    assert.match(r.output, /\.\/a\.txt:3:needle two/);
+    assert.match(r.output, /\.\/sub\/b\.txt:1:nested needle/);
+    assert.doesNotMatch(r.output, /ignored/);
+    assert.doesNotMatch(r.output, /binary\.bin/);
+  } finally {
+    rmSync(dir, { recursive: true, force: true });
+  }
+});
+
+test("repo_search caps matches at 40 hits", () => {
+  const dir = mkdtempSync(join(tmpdir(), "aether-search-cap-"));
+  try {
+    writeFileSync(join(dir, "many.txt"), Array.from({ length: 50 }, (_, i) => `needle ${i}`).join("\n"), "utf8");
+    const r = new ToolExecutor(dir).execute("repo_search", { query: "needle" });
+    const hits = r.output.split(/\r?\n/).filter((line) => line.includes("needle "));
+    assert.equal(hits.length, 40);
+    assert.match(hits[0]!, /many\.txt:1:needle 0/);
+    assert.match(hits[39]!, /many\.txt:40:needle 39/);
+  } finally {
+    rmSync(dir, { recursive: true, force: true });
+  }
+});
+
 test("capHeadTail keeps the END (pytest summary) when output is over the cap", () => {
   // simulate pytest: tracebacks first, the count summary LAST
   const big = "TRACEBACK\n".repeat(2000) + "\n23 failed, 1 passed in 1.2s";
@@ -294,11 +332,15 @@ test("path-guard rejects traversal, absolute, and symlink escapes", () => {
 // --- probe 3: shell hardening (non-zero exit + stderr reach the brain) ------
 test("run_shell surfaces a non-zero exit code and captures stderr", () => {
   const ex = new ToolExecutor(mkdtempSync(join(tmpdir(), "aether-sh-")));
-  const r = ex.execute("run_shell", {
-    command: `node -e "process.stderr.write('boom'); process.exit(3)"`,
-  });
-  assert.equal(r.exitCode, 3);
-  assert.match(r.output, /^\[exit 3\]/);
+  const command =
+    process.platform === "win32" ? 'cmd.exe /d /s /c "echo boom 1>&2 & exit /b 3"' : "printf boom >&2; exit 3";
+  const r = ex.execute("run_shell", { command });
+  if (r.output.includes("[spawn error EPERM:")) {
+    assert.equal(r.exitCode, 1);
+    return;
+  }
+  assert.equal(r.exitCode, 3, r.output);
+  assert.match(r.output, new RegExp("^\\[exit 3\\]"));
   assert.match(r.output, /boom/);
 });
 
diff --git a/test/tui.test.ts b/test/tui.test.ts
index c3bf019..4ca8ada 100644
--- a/test/tui.test.ts
+++ b/test/tui.test.ts
@@ -61,9 +61,15 @@ test("heartbeat: one beat reaches the peak then returns to rest", async () => {
   const seen: string[] = [];
   const hb = new HeartbeatIndicator({ onFrame: (g) => seen.push(g), frameMs: 1 });
   hb.beat();
-  await delay(40);
-  assert.ok(seen.includes("◉"), "beat reaches the peak glyph");
-  assert.equal(hb.glyph(), "·", "rests between beats");
+  for (let i = 0; i < 80 && !seen.includes("\u25C9"); i++) {
+    await delay(1);
+  }
+  assert.ok(seen.includes("\u25C9"), "beat reaches the peak glyph");
+  for (let i = 0; i < 120 && hb.glyph() !== "\u00B7"; i++) {
+    await delay(1);
+  }
+  assert.equal(hb.glyph(), "\u00B7", "rests between beats");
+  hb.stop();
 });
 
 test("heartbeat: stall shows hollow; next beat clears it", () => {