diff --git a/src/tools/grep/cli.ts b/src/tools/grep/cli.ts
index c44bda377..1a6cd89d0 100644
--- a/src/tools/grep/cli.ts
+++ b/src/tools/grep/cli.ts
@@ -1,6 +1,7 @@
 import { spawn } from "bun"
 import {
   resolveGrepCli,
+  type ResolvedCli,
   type GrepBackend,
   DEFAULT_MAX_DEPTH,
   DEFAULT_MAX_FILESIZE,
@@ -148,17 +149,17 @@ function parseCountOutput(output: string): CountResult[] {
   return results
 }
 
-export async function runRg(options: GrepOptions): Promise<GrepResult> {
+export async function runRg(options: GrepOptions, resolvedCli?: ResolvedCli): Promise<GrepResult> {
   await rgSemaphore.acquire()
   try {
-    return await runRgInternal(options)
+    return await runRgInternal(options, resolvedCli)
   } finally {
     rgSemaphore.release()
   }
 }
 
-async function runRgInternal(options: GrepOptions): Promise<GrepResult> {
-  const cli = resolveGrepCli()
+async function runRgInternal(options: GrepOptions, resolvedCli?: ResolvedCli): Promise<GrepResult> {
+  const cli = resolvedCli ?? resolveGrepCli()
   const args = buildArgs(options, cli.backend)
   const timeout = Math.min(options.timeout ?? DEFAULT_TIMEOUT_MS, DEFAULT_TIMEOUT_MS)
 
@@ -224,17 +225,23 @@ async function runRgInternal(options: GrepOptions): Promise<GrepResult> {
   }
 }
 
-export async function runRgCount(options: Omit<GrepOptions, "context">): Promise<CountResult[]> {
+export async function runRgCount(
+  options: Omit<GrepOptions, "context">,
+  resolvedCli?: ResolvedCli
+): Promise<CountResult[]> {
   await rgSemaphore.acquire()
   try {
-    return await runRgCountInternal(options)
+    return await runRgCountInternal(options, resolvedCli)
   } finally {
     rgSemaphore.release()
   }
 }
 
-async function runRgCountInternal(options: Omit<GrepOptions, "context">): Promise<CountResult[]> {
-  const cli = resolveGrepCli()
+async function runRgCountInternal(
+  options: Omit<GrepOptions, "context">,
+  resolvedCli?: ResolvedCli
+): Promise<CountResult[]> {
+  const cli = resolvedCli ?? resolveGrepCli()
   const args = buildArgs({ ...options, context: 0 }, cli.backend)
 
   if (cli.backend === "rg") {
diff --git a/src/tools/grep/constants.ts b/src/tools/grep/constants.ts
index 524fddd4b..f41284324 100644
--- a/src/tools/grep/constants.ts
+++ b/src/tools/grep/constants.ts
@@ -3,10 +3,11 @@ import { join, dirname } from "node:path"
 import { spawnSync } from "node:child_process"
 import { getInstalledRipgrepPath, downloadAndInstallRipgrep } from "./downloader"
 import { getDataDir } from "../../shared/data-path"
+import { log } from "../../shared/logger"
 
 export type GrepBackend = "rg" | "grep"
 
-interface ResolvedCli {
+export interface ResolvedCli {
   path: string
   backend: GrepBackend
 }
@@ -89,7 +90,7 @@ export function resolveGrepCli(): ResolvedCli {
 export async function resolveGrepCliWithAutoInstall(): Promise<ResolvedCli> {
   const current = resolveGrepCli()
 
-  if (current.backend === "rg") {
+  if (current.backend === "rg" && current.path !== "rg") {
     return current
   }
 
@@ -103,7 +104,18 @@ export async function resolveGrepCliWithAutoInstall(): Promise<ResolvedCli> {
     const rgPath = await downloadAndInstallRipgrep()
     cachedCli = { path: rgPath, backend: "rg" }
     return cachedCli
-  } catch {
+  } catch (error) {
+    if (current.backend === "grep") {
+      log("[oh-my-opencode] Failed to auto-install ripgrep. Falling back to GNU grep.", {
+        error: error instanceof Error ? error.message : String(error),
+        grep_path: current.path,
+      })
+    } else {
+      log("[oh-my-opencode] Failed to auto-install ripgrep and GNU grep was not found.", {
+        error: error instanceof Error ? error.message : String(error),
+      })
+    }
+
     return current
   }
 }
diff --git a/src/tools/grep/tools.ts b/src/tools/grep/tools.ts
index b00c47540..eaf8a3972 100644
--- a/src/tools/grep/tools.ts
+++ b/src/tools/grep/tools.ts
@@ -2,6 +2,7 @@ import { resolve } from "node:path"
 import type { PluginInput } from "@opencode-ai/plugin"
 import { tool, type ToolDefinition } from "@opencode-ai/plugin/tool"
 import { runRg, runRgCount } from "./cli"
+import { resolveGrepCliWithAutoInstall } from "./constants"
 import { formatGrepResult, formatCountResult } from "./result-formatter"
 
 export function createGrepTools(ctx: PluginInput): Record<string, ToolDefinition> {
@@ -42,13 +43,14 @@ export function createGrepTools(ctx: PluginInput): Record<string, ToolDefinition
         const paths = [searchPath]
         const outputMode = args.output_mode ?? "files_with_matches"
         const headLimit = args.head_limit ?? 0
+        const cli = await resolveGrepCliWithAutoInstall()
 
         if (outputMode === "count") {
           const results = await runRgCount({
             pattern: args.pattern,
             paths,
             globs,
-          })
+          }, cli)
           const limited = headLimit > 0 ? results.slice(0, headLimit) : results
           return formatCountResult(limited)
         }
@@ -60,7 +62,7 @@ export function createGrepTools(ctx: PluginInput): Record<string, ToolDefinition
           context: 0,
           outputMode,
           headLimit,
-        })
+        }, cli)
 
         return formatGrepResult(result)
       } catch (e) {