fix(agents): add anti-duplication rules to Prometheus and Metis agents

- Import and inject buildAntiDuplicationSection() in all 3 Prometheus variants (interview-mode, gpt, gemini) and Metis
- Added tests verifying anti-dup section presence in all prompt variants
- Completes anti-duplication coverage for all delegating agents

src/agents/anti-duplication.test.ts

@@ -2,6 +2,7 @@
 
 import { describe, it, expect } from "bun:test"
 import { buildAntiDuplicationSection } from "./dynamic-agent-prompt-builder"
+import { METIS_SYSTEM_PROMPT } from "./metis"
 
 describe("buildAntiDuplicationSection", () => {
   it("#given no arguments #when building anti-duplication section #then returns comprehensive rule section", () => {
@@ -90,3 +91,16 @@ describe("buildAntiDuplicationSection", () => {
     expect(result).toContain("</Anti_Duplication>")
   })
 })
+
+describe("METIS_SYSTEM_PROMPT anti-duplication coverage", () => {
+  it("#given the system prompt #when reading delegated exploration rules #then includes anti-duplication guidance", () => {
+    // given
+    const prompt = METIS_SYSTEM_PROMPT
+
+    // when / then
+    expect(prompt).toContain("<Anti_Duplication>")
+    expect(prompt).toContain("Anti-Duplication Rule")
+    expect(prompt).toContain("DO NOT perform the same search yourself")
+    expect(prompt).toContain("non-overlapping work")
+  })
+})

src/agents/metis.ts

@@ -1,5 +1,6 @@
 import type { AgentConfig } from "@opencode-ai/sdk"
 import type { AgentMode, AgentPromptMetadata } from "./types"
+import { buildAntiDuplicationSection } from "../dynamic-agent-prompt-builder"
 import { createAgentToolRestrictions } from "../shared/permission-compat"
 
 const MODE: AgentMode = "subagent"
@@ -25,6 +26,8 @@ export const METIS_SYSTEM_PROMPT = `# Metis - Pre-Planning Consultant
 - **READ-ONLY**: You analyze, question, advise. You do NOT implement or modify files.
 - **OUTPUT**: Your analysis feeds into Prometheus (planner). Be actionable.
 
+${buildAntiDuplicationSection()}
+
 ---
 
 ## PHASE 0: INTENT CLASSIFICATION (MANDATORY FIRST STEP)

src/agents/prometheus-prompt.test.ts

@@ -1,5 +1,7 @@
 import { describe, test, expect } from "bun:test"
 import { PROMETHEUS_SYSTEM_PROMPT } from "./prometheus"
+import { PROMETHEUS_GPT_SYSTEM_PROMPT } from "./prometheus/gpt"
+import { PROMETHEUS_GEMINI_SYSTEM_PROMPT } from "./prometheus/gemini"
 
 describe("PROMETHEUS_SYSTEM_PROMPT Momus invocation policy", () => {
   test("should direct providing ONLY the file path string when invoking Momus", () => {
@@ -82,3 +84,22 @@ describe("PROMETHEUS_SYSTEM_PROMPT zero human intervention", () => {
     expect(lowerPrompt).toMatch(/zero acceptance criteria require human/)
   })
 })
+
+describe("Prometheus prompts anti-duplication coverage", () => {
+  test("all variants should include anti-duplication rules for delegated exploration", () => {
+    // given
+    const prompts = [
+      PROMETHEUS_SYSTEM_PROMPT,
+      PROMETHEUS_GPT_SYSTEM_PROMPT,
+      PROMETHEUS_GEMINI_SYSTEM_PROMPT,
+    ]
+
+    // when / then
+    for (const prompt of prompts) {
+      expect(prompt).toContain("<Anti_Duplication>")
+      expect(prompt).toContain("Anti-Duplication Rule")
+      expect(prompt).toContain("DO NOT perform the same search yourself")
+      expect(prompt).toContain("non-overlapping work")
+    }
+  })
+})

src/agents/prometheus/gemini.ts

@@ -9,6 +9,8 @@
  * - Tool-call mandate for every phase transition
  */
 
+import { buildAntiDuplicationSection } from "../dynamic-agent-prompt-builder"
+
 export const PROMETHEUS_GEMINI_SYSTEM_PROMPT = `
 <identity>
 You are Prometheus - Strategic Planning Consultant from OhMyOpenCode.
@@ -43,6 +45,8 @@ A plan is "decision complete" when the implementer needs ZERO judgment calls —
 This is your north star quality metric.
 </mission>
 
+${buildAntiDuplicationSection()}
+
 <core_principles>
 ## Three Principles
 
@@ -325,4 +329,4 @@ You are Prometheus, the strategic planning consultant. You bring foresight and s
 
 export function getGeminiPrometheusPrompt(): string {
   return PROMETHEUS_GEMINI_SYSTEM_PROMPT
-}
+}

src/agents/prometheus/gpt.ts

@@ -8,6 +8,8 @@
  * - Principle-driven: Decision Complete, Explore Before Asking, Two Kinds of Unknowns
  */
 
+import { buildAntiDuplicationSection } from "../dynamic-agent-prompt-builder";
+
 export const PROMETHEUS_GPT_SYSTEM_PROMPT = `
 <identity>
 You are Prometheus - Strategic Planning Consultant from OhMyOpenCode.
@@ -25,6 +27,8 @@ A plan is "decision complete" when the implementer needs ZERO judgment calls —
 This is your north star quality metric.
 </mission>
 
+${buildAntiDuplicationSection()}
+
 <core_principles>
 ## Three Principles (Read First)
 

src/agents/prometheus/interview-mode.ts

@@ -5,6 +5,8 @@
  * Includes intent classification, research patterns, and anti-patterns.
  */
 
+import { buildAntiDuplicationSection } from "../dynamic-agent-prompt-builder"
+
 export const PROMETHEUS_INTERVIEW_MODE = `# PHASE 1: INTERVIEW MODE (DEFAULT)
 
 ## Step 0: Intent Classification (EVERY request)
@@ -29,6 +31,8 @@ Before diving into consultation, classify the work intent. This determines your
 - **Simple** (1-2 files, clear scope, <30 min work) — **Lightweight**: 1-2 targeted questions → propose approach.
 - **Complex** (3+ files, multiple components, architectural impact) — **Full consultation**: Intent-specific deep interview.
 
+${buildAntiDuplicationSection()}
+
 ---
 
 ## Intent-Specific Interview Strategies