diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 3bffd4e81..631024028 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -43,3 +43,6 @@ export type { SessionManagerDeps } from "./session-manager.js";
 // Lifecycle manager — state machine + reaction engine
 export { createLifecycleManager } from "./lifecycle-manager.js";
 export type { LifecycleManagerDeps } from "./lifecycle-manager.js";
+
+// Shared utilities
+export { shellEscape } from "./utils.js";
diff --git a/packages/core/src/utils.ts b/packages/core/src/utils.ts
new file mode 100644
index 000000000..7724829d9
--- /dev/null
+++ b/packages/core/src/utils.ts
@@ -0,0 +1,13 @@
+/**
+ * Shared utility functions for agent-orchestrator plugins.
+ */
+
+/**
+ * POSIX-safe shell escaping: wraps value in single quotes,
+ * escaping any embedded single quotes as '\\'' .
+ *
+ * Safe for use in both `sh -c` and `execFile` contexts.
+ */
+export function shellEscape(arg: string): string {
+  return "'" + arg.replace(/'/g, "'\\''") + "'";
+}
diff --git a/packages/plugins/agent-aider/src/index.ts b/packages/plugins/agent-aider/src/index.ts
index 207fd46b9..64d4619fe 100644
--- a/packages/plugins/agent-aider/src/index.ts
+++ b/packages/plugins/agent-aider/src/index.ts
@@ -1,11 +1,12 @@
-import type {
-  Agent,
-  AgentIntrospection,
-  AgentLaunchConfig,
-  ActivityState,
-  PluginModule,
-  RuntimeHandle,
-  Session,
+import {
+  shellEscape,
+  type Agent,
+  type AgentIntrospection,
+  type AgentLaunchConfig,
+  type ActivityState,
+  type PluginModule,
+  type RuntimeHandle,
+  type Session,
 } from "@agent-orchestrator/core";
 import { execFile } from "node:child_process";
 import { promisify } from "node:util";
@@ -27,14 +28,6 @@ export const manifest = {
 // Agent Implementation
 // =============================================================================
 
-/**
- * POSIX-safe shell escaping: wraps value in single quotes,
- * escaping any embedded single quotes as '\'' .
- */
-function shellEscape(arg: string): string {
-  return "'" + arg.replace(/'/g, "'\\''") + "'";
-}
-
 function createAiderAgent(): Agent {
   return {
     name: "aider",
diff --git a/packages/plugins/agent-claude-code/src/index.ts b/packages/plugins/agent-claude-code/src/index.ts
index 08c100296..34b528750 100644
--- a/packages/plugins/agent-claude-code/src/index.ts
+++ b/packages/plugins/agent-claude-code/src/index.ts
@@ -1,12 +1,13 @@
-import type {
-  Agent,
-  AgentIntrospection,
-  AgentLaunchConfig,
-  ActivityState,
-  CostEstimate,
-  PluginModule,
-  RuntimeHandle,
-  Session,
+import {
+  shellEscape,
+  type Agent,
+  type AgentIntrospection,
+  type AgentLaunchConfig,
+  type ActivityState,
+  type CostEstimate,
+  type PluginModule,
+  type RuntimeHandle,
+  type Session,
 } from "@agent-orchestrator/core";
 import { execFile } from "node:child_process";
 import { readdir, readFile, stat } from "node:fs/promises";
@@ -197,18 +198,6 @@ function extractCost(lines: JsonlLine[]): CostEstimate | undefined {
   return { inputTokens, outputTokens, estimatedCostUsd: totalCost };
 }
 
-// =============================================================================
-// Shell Escaping
-// =============================================================================
-
-/**
- * POSIX-safe shell escaping: wraps value in single quotes,
- * escaping any embedded single quotes as '\'' .
- */
-function shellEscape(arg: string): string {
-  return "'" + arg.replace(/'/g, "'\\''") + "'";
-}
-
 // =============================================================================
 // Activity Detection Patterns
 // =============================================================================
diff --git a/packages/plugins/agent-codex/src/index.ts b/packages/plugins/agent-codex/src/index.ts
index 6a2bc4c51..5a0a38a76 100644
--- a/packages/plugins/agent-codex/src/index.ts
+++ b/packages/plugins/agent-codex/src/index.ts
@@ -1,11 +1,12 @@
-import type {
-  Agent,
-  AgentIntrospection,
-  AgentLaunchConfig,
-  ActivityState,
-  PluginModule,
-  RuntimeHandle,
-  Session,
+import {
+  shellEscape,
+  type Agent,
+  type AgentIntrospection,
+  type AgentLaunchConfig,
+  type ActivityState,
+  type PluginModule,
+  type RuntimeHandle,
+  type Session,
 } from "@agent-orchestrator/core";
 import { execFile } from "node:child_process";
 import { promisify } from "node:util";
@@ -27,14 +28,6 @@ export const manifest = {
 // Agent Implementation
 // =============================================================================
 
-/**
- * POSIX-safe shell escaping: wraps value in single quotes,
- * escaping any embedded single quotes as '\'' .
- */
-function shellEscape(arg: string): string {
-  return "'" + arg.replace(/'/g, "'\\''") + "'";
-}
-
 function createCodexAgent(): Agent {
   return {
     name: "codex",