feat(agents): add Plan Agent dependency and strengthen Deep Parallel Delegation for non-Claude models

Non-Claude models skip planning and under-parallelize. Two new sections
injected only when model is not Claude:

- Plan Agent Dependency: multi-step tasks MUST consult Plan Agent first,
  use session_id for follow-ups, ask aggressively when ambiguous
- Deep Parallel Delegation (rewrite): explicit '4 units = 4 agents'
  pattern, each with clear GOAL + success criteria, all run_in_background

src/agents/dynamic-agent-prompt-builder.test.ts

@@ -4,6 +4,8 @@ import { describe, it, expect } from "bun:test"
 import {
   buildCategorySkillsDelegationGuide,
   buildUltraworkSection,
+  buildDeepParallelSection,
+  buildNonClaudePlannerSection,
   type AvailableSkill,
   type AvailableCategory,
   type AvailableAgent,
@@ -172,4 +174,86 @@ describe("buildUltraworkSection", () => {
   })
 })
 
+describe("buildDeepParallelSection", () => {
+  const deepCategory: AvailableCategory = { name: "deep", description: "Autonomous problem-solving" }
+  const otherCategory: AvailableCategory = { name: "quick", description: "Trivial tasks" }
+
+  it("#given non-Claude model with deep category #when building #then returns parallel delegation section", () => {
+    //#given
+    const model = "google/gemini-3-pro"
+    const categories = [deepCategory, otherCategory]
+
+    //#when
+    const result = buildDeepParallelSection(model, categories)
+
+    //#then
+    expect(result).toContain("Deep Parallel Delegation")
+    expect(result).toContain("EVERY independent unit")
+    expect(result).toContain("run_in_background=true")
+    expect(result).toContain("4 independent units")
+  })
+
+  it("#given Claude model #when building #then returns empty", () => {
+    //#given
+    const model = "anthropic/claude-opus-4-6"
+    const categories = [deepCategory]
+
+    //#when
+    const result = buildDeepParallelSection(model, categories)
+
+    //#then
+    expect(result).toBe("")
+  })
+
+  it("#given non-Claude model without deep category #when building #then returns empty", () => {
+    //#given
+    const model = "openai/gpt-5.2"
+    const categories = [otherCategory]
+
+    //#when
+    const result = buildDeepParallelSection(model, categories)
+
+    //#then
+    expect(result).toBe("")
+  })
+})
+
+describe("buildNonClaudePlannerSection", () => {
+  it("#given non-Claude model #when building #then returns plan agent section", () => {
+    //#given
+    const model = "google/gemini-3-pro"
+
+    //#when
+    const result = buildNonClaudePlannerSection(model)
+
+    //#then
+    expect(result).toContain("Plan Agent")
+    expect(result).toContain("session_id")
+    expect(result).toContain("Multi-step")
+  })
+
+  it("#given Claude model #when building #then returns empty", () => {
+    //#given
+    const model = "anthropic/claude-sonnet-4-6"
+
+    //#when
+    const result = buildNonClaudePlannerSection(model)
+
+    //#then
+    expect(result).toBe("")
+  })
+
+  it("#given GPT model #when building #then returns plan agent section", () => {
+    //#given
+    const model = "openai/gpt-5.2"
+
+    //#when
+    const result = buildNonClaudePlannerSection(model)
+
+    //#then
+    expect(result).toContain("Plan Agent")
+    expect(result).not.toBe("")
+  })
+})
+
 

src/agents/dynamic-agent-prompt-builder.ts

@@ -316,6 +316,22 @@ export function buildAntiPatternsSection(): string {
 ${patterns.join("\n")}`
 }
 
+export function buildNonClaudePlannerSection(model: string): string {
+  const isNonClaude = !model.toLowerCase().includes('claude')
+  if (!isNonClaude) return ""
+
+  return `### Plan Agent Dependency (Non-Claude)
+
+Multi-step task? **ALWAYS consult Plan Agent first.** Do NOT start implementation without a plan.
+
+- Single-file fix or trivial change → proceed directly
+- Anything else (2+ steps, unclear scope, architecture) → \`task(subagent_type="plan", ...)\` FIRST
+- Use \`session_id\` to resume the same Plan Agent — ask follow-up questions aggressively
+- If ANY part of the task is ambiguous, ask Plan Agent before guessing
+
+Plan Agent returns a structured work breakdown with parallel execution opportunities. Follow it.`
+}
+
 export function buildDeepParallelSection(model: string, categories: AvailableCategory[]): string {
   const isNonClaude = !model.toLowerCase().includes('claude')
   const hasDeepCategory = categories.some(c => c.name === 'deep')
@@ -324,12 +340,13 @@ export function buildDeepParallelSection(model: string, categories: AvailableCat
 
   return `### Deep Parallel Delegation
 
-For implementation tasks, actively decompose and delegate to \`deep\` category agents in parallel.
+Delegate EVERY independent unit to a \`deep\` agent in parallel (\`run_in_background=true\`).
+If a task decomposes into 4 independent units, spawn 4 agents simultaneously — not 1 at a time.
 
-1. Break the implementation into independent work units
-2. Maximize parallel deep agents — spawn one per independent unit (\`run_in_background=true\`)
-3. Give each agent a GOAL, not step-by-step instructions — deep agents explore and solve autonomously
-4. Collect results, integrate, verify coherence`
+1. Decompose the implementation into independent work units
+2. Assign one \`deep\` agent per unit — all via \`run_in_background=true\`
+3. Give each agent a clear GOAL with success criteria, not step-by-step instructions
+4. Collect all results, integrate, verify coherence across units`
 }
 
 export function buildUltraworkSection(

src/agents/sisyphus.ts

@@ -6,6 +6,8 @@ import {
   buildGeminiDelegationOverride,
   buildGeminiVerificationOverride,
   buildGeminiIntentGateEnforcement,
+  buildGeminiToolGuide,
+  buildGeminiToolCallExamples,
 } from "./sisyphus-gemini-overlays";
 
 const MODE: AgentMode = "all";
@@ -32,6 +34,7 @@ import {
   buildHardBlocksSection,
   buildAntiPatternsSection,
   buildDeepParallelSection,
+  buildNonClaudePlannerSection,
   categorizeTools,
 } from "./dynamic-agent-prompt-builder";
 
@@ -170,6 +173,7 @@ function buildDynamicSisyphusPrompt(
   const hardBlocks = buildHardBlocksSection();
   const antiPatterns = buildAntiPatternsSection();
   const deepParallelSection = buildDeepParallelSection(model, availableCategories);
+  const nonClaudePlannerSection = buildNonClaudePlannerSection(model);
   const taskManagementSection = buildTaskManagementSection(useTaskSystem);
   const todoHookNote = useTaskSystem
     ? "YOUR TASK CREATION WOULD BE TRACKED BY HOOK([SYSTEM REMINDER - TASK CONTINUATION])"
@@ -364,6 +368,8 @@ STOP searching when:
 
 ${categorySkillsGuide}
 
+${nonClaudePlannerSection}
+
 ${deepParallelSection}
 
 ${delegationTable}
@@ -564,12 +570,25 @@ export function createSisyphusAgent(
     : buildDynamicSisyphusPrompt(model, [], tools, skills, categories, useTaskSystem);
 
   if (isGeminiModel(model)) {
+    // 1. Intent gate + tool mandate — early in prompt (after intent verbalization)
     prompt = prompt.replace(
       "</intent_verbalization>",
       `</intent_verbalization>\n\n${buildGeminiIntentGateEnforcement()}\n\n${buildGeminiToolMandate()}`
     );
-    prompt += "\n" + buildGeminiDelegationOverride();
-    prompt += "\n" + buildGeminiVerificationOverride();
+
+    // 2. Tool guide + examples — after tool_usage_rules (where tools are discussed)
+    prompt = prompt.replace(
+      "</tool_usage_rules>",
+      `</tool_usage_rules>\n\n${buildGeminiToolGuide()}\n\n${buildGeminiToolCallExamples()}`
+    );
+
+    // 3. Delegation + verification overrides — before Constraints (NOT at prompt end)
+    //    Gemini suffers from lost-in-the-middle: content at prompt end gets weaker attention.
+    //    Placing these before <Constraints> ensures they're in a high-attention zone.
+    prompt = prompt.replace(
+      "<Constraints>",
+      `${buildGeminiDelegationOverride()}\n\n${buildGeminiVerificationOverride()}\n\n<Constraints>`
+    );
   }
 
   const permission = {