From a93a1ebd65f381baf4028d4604e10525c70e91e4 Mon Sep 17 00:00:00 2001
From: Abhi <43648792+abhipatel12@users.noreply.github.com>
Date: Fri, 3 Apr 2026 14:45:11 -0400
Subject: [PATCH] fix(core): inject skill system instructions into subagent
 prompts if activated (#24620)

---
 packages/core/src/agents/local-executor.ts | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/packages/core/src/agents/local-executor.ts b/packages/core/src/agents/local-executor.ts
index 50a93ec7ff..81cd27abee 100644
--- a/packages/core/src/agents/local-executor.ts
+++ b/packages/core/src/agents/local-executor.ts
@@ -30,7 +30,7 @@ import { CompressionStatus } from '../core/turn.js';
 import { type ToolCallRequestInfo } from '../scheduler/types.js';
 import { ChatCompressionService } from '../context/chatCompressionService.js';
 import { getDirectoryContextString } from '../utils/environmentContext.js';
-import { renderUserMemory } from '../prompts/snippets.js';
+import { renderUserMemory, renderAgentSkills } from '../prompts/snippets.js';
 import { promptIdContext } from '../utils/promptIdContext.js';
 import {
   logAgentStart,
@@ -78,7 +78,10 @@ import {
   runWithScopedWorkspaceContext,
 } from '../config/scoped-config.js';
 import { CompleteTaskTool } from '../tools/complete-task.js';
-import { COMPLETE_TASK_TOOL_NAME } from '../tools/definitions/base-declarations.js';
+import {
+  COMPLETE_TASK_TOOL_NAME,
+  ACTIVATE_SKILL_TOOL_NAME,
+} from '../tools/definitions/base-declarations.js';
 
 /** A callback function to report on agent activity. */
 export type ActivityCallback = (activity: SubagentActivityEvent) => void;
@@ -1318,6 +1321,21 @@ export class LocalAgentExecutor<TOutput extends z.ZodTypeAny> {
     // Inject user inputs into the prompt template.
     let finalPrompt = templateString(promptConfig.systemPrompt, inputs);
 
+    // Inject skill SI if ACTIVATE_SKILL_TOOL_NAME is available to this agent.
+    if (this.toolRegistry.getTool(ACTIVATE_SKILL_TOOL_NAME) !== undefined) {
+      const skills = this.context.config.getSkillManager().getSkills();
+      if (skills.length > 0) {
+        const skillsPrompt = renderAgentSkills(
+          skills.map((s) => ({
+            name: s.name,
+            description: s.description,
+            location: s.location,
+          })),
+        );
+        finalPrompt += `\n\n${skillsPrompt}`;
+      }
+    }
+
     // Append memory context if available.
     const systemMemory = this.context.config.getSystemInstructionMemory();
     if (systemMemory) {