diff --git a/packages/opencode/script/glob-perf.ts b/packages/opencode/script/glob-perf.ts
new file mode 100644
index 000000000..3f672f601
--- /dev/null
+++ b/packages/opencode/script/glob-perf.ts
@@ -0,0 +1,65 @@
+#!/usr/bin/env bun
+import fs from "fs/promises"
+import os from "os"
+import path from "path"
+import { performance } from "perf_hooks"
+import { Ripgrep } from "../src/file/ripgrep"
+
+const root = await fs.mkdtemp(path.join(os.tmpdir(), "glob-perf-"))
+const scaleInput = process.env.GLOB_PERF_SCALE ?? "1"
+const scale = Number.isNaN(Number(scaleInput)) ? 1 : Math.max(1, Number(scaleInput))
+
+async function makeTree() {
+  const branches = 40 * scale
+  const subs = 12 * scale
+  const filesPerDir = 40
+  const content = "x".repeat(256)
+
+  const tasks: Promise<unknown>[] = []
+  for (const b of Array.from({ length: branches }).map((_, i) => i)) {
+    const base = path.join(root, `dir${b}`)
+    tasks.push(
+      fs.mkdir(base, { recursive: true }).then(async () => {
+        for (const s of Array.from({ length: subs }).map((_, j) => j)) {
+          const sub = path.join(base, `sub${s}`)
+          await fs.mkdir(sub, { recursive: true })
+          for (const f of Array.from({ length: filesPerDir }).map((_, k) => k)) {
+            await Bun.write(path.join(sub, `file${f}.txt`), content)
+          }
+        }
+      }),
+    )
+  }
+  await Promise.all(tasks)
+}
+
+async function makeSymlinkLoop() {
+  const loopRoot = path.join(root, "loop")
+  await fs.mkdir(loopRoot, { recursive: true })
+  await Bun.write(path.join(loopRoot, "loop-file.txt"), "loop")
+  await fs.symlink(loopRoot, path.join(loopRoot, "cycle"))
+}
+
+async function runScan(label: string, follow: boolean) {
+  const start = performance.now()
+  const files = await Array.fromAsync(
+    Ripgrep.files({
+      cwd: root,
+      follow,
+      timeoutMs: 5000,
+    }),
+  ).catch((e) => {
+    console.log(`${label}: error ${e}`)
+    return [] as string[]
+  })
+  const ms = Math.round(performance.now() - start)
+  console.log(`${label}: files=${files.length} time=${ms}ms follow=${follow}`)
+}
+
+await makeTree()
+await makeSymlinkLoop()
+
+await runScan("no-follow", false)
+await runScan("with-follow", true)
+
+await fs.rm(root, { recursive: true, force: true })
diff --git a/packages/opencode/src/tool/glob.ts b/packages/opencode/src/tool/glob.ts
index 267f58c37..aca4ef797 100644
--- a/packages/opencode/src/tool/glob.ts
+++ b/packages/opencode/src/tool/glob.ts
@@ -14,6 +14,9 @@ const DEFAULT_IGNORE = [
   "**/__pycache__/**",
 ]
 
+const FOLLOW_WARNING =
+  "Following symlinks can scan large or cyclical directories and may spike CPU. Only enable if you need it."
+
 export const GlobTool = Tool.define("glob", {
   description: DESCRIPTION,
   parameters: z.object({
@@ -87,6 +90,10 @@ export const GlobTool = Tool.define("glob", {
         output.push("(Results are truncated. Consider using a more specific path or pattern.)")
       }
     }
+    if (params.follow) {
+      output.push("")
+      output.push(FOLLOW_WARNING)
+    }
 
     return {
       title: path.relative(Instance.worktree, search),