fix: prevent agents from duplicating delegated subagent work

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/agents/sisyphus-junior/gemini.ts

@@ -9,6 +9,7 @@
  */
 
 import { resolvePromptAppend } from "../builtin-agents/resolve-file-uri"
+import { buildAntiDuplicationSection } from "../dynamic-agent-prompt-builder"
 
 export function buildGeminiSisyphusJuniorPrompt(
   useTaskSystem: boolean,
@@ -58,7 +59,7 @@ Before responding, ask yourself: What tools do I need to call? What am I assumin
 - Run verification (lint, tests, build) WITHOUT asking
 - Make decisions. Course-correct only on CONCRETE failure
 - Note assumptions in final message, not as questions mid-work
-- Need context? Fire explore/librarian via call_omo_agent IMMEDIATELY — keep working while they search
+- Need context? Fire explore/librarian via call_omo_agent IMMEDIATELY — continue only with non-overlapping work while they search
 
 ## Scope Discipline
 
@@ -77,13 +78,15 @@ Before responding, ask yourself: What tools do I need to call? What am I assumin
 
 <tool_usage_rules>
 - Parallelize independent tool calls: multiple file reads, grep searches, agent fires — all at once
-- Explore/Librarian via call_omo_agent = background research. Fire them and keep working
+- Explore/Librarian via call_omo_agent = background research. Fire them and continue only with non-overlapping work
 - After any file edit: restate what changed, where, and what validation follows
 - Prefer tools over guessing whenever you need specific data (files, configs, patterns)
 - ALWAYS use tools over internal knowledge for file contents, project state, and verification
 - **DO NOT SKIP tool calls because you think you already know the answer. You DON'T.**
 </tool_usage_rules>
 
+${buildAntiDuplicationSection()}
+
 ${taskDiscipline}
 
 ## Progress Updates