dispatching-parallel-agents

Dispatching Parallel Agents

Overview

When you have multiple unrelated failures (different test files, different subsystems, different bugs), investigating them sequentially wastes time. Each investigation is independent and can happen in parallel.

Core principle: Dispatch one agent per independent problem domain. Let them work concurrently.

Step 0: Load Document Context (文档上下文传递)

Before dispatching agents:

IF .horspowers-config.yaml exists AND documentation.enabled: true:

1. Read task document path (if set):

   # 检查任务文档是否存在
   if [ -n "$TASK_DOC" ] && [ -f "$TASK_DOC" ]; then
     echo "✅ 任务文档: $TASK_DOC"
     cat "$TASK_DOC"
   elif [ -n "$TASK_DOC" ]; then
     # 文档路径设置但文件不存在 - 增强处理
     echo "⚠️  警告: TASK_DOC 已设置但文件不存在: $TASK_DOC"
     echo ""
   
     # 尝试搜索相关文档
     echo "🔍 搜索相关文档..."
     RECENT_TASKS=$(find docs/active -name "task*.md" -mtime -7 2>/dev/null | head -3)
     if [ -n "$RECENT_TASKS" ]; then
       echo "最近的任务文档:"
       echo "$RECENT_TASKS"
     fi
   
     # 从 git log 获取上下文
     echo ""
     echo "📝 从 git 获取上下文..."
     git log --oneline -5 2>/dev/null || true
     CURRENT_BRANCH=$(git branch --show-current 2>/dev/null || echo "unknown")
     echo "当前分支: $CURRENT_BRANCH"
   
     # 提供流程引导建议
     echo ""
     echo "💡 推荐工作流程:"
     echo "   完整流程: brainstorming → writing-plans → (当前技能)"
     echo ""
   
     # 检查文档系统是否初始化
     if [ ! -d "docs/active" ]; then
       echo "📋 文档系统未初始化。运行 'horspowers:document-management' 初始化文档系统。"
     fi
   
     echo "继续使用可用上下文分发代理..."
   fi
   

2. Read related documents (if specified in task document):

   # 设计文档 (如果在任务文档中链接)
   DESIGN_DOC="docs/plans/YYYY-MM-DD-design-<topic>.md"
   if [ -f "$DESIGN_DOC" ]; then
     echo "✅ 设计文档: $DESIGN_DOC"
     cat "$DESIGN_DOC"
   fi
   
   # 计划文档 (如果在任务文档中链接)
   PLAN_DOC="docs/plans/YYYY-MM-DD-<feature>.md"
   if [ -f "$PLAN_DOC" ]; then
     echo "✅ 计划文档: $PLAN_DOC"
     cat "$PLAN_DOC"
   fi
   

3. Prepare document context for each agent: Each agent prompt should include:

   • Relevant document paths (for reference)
   • Task/Plan/Design context snippets
   • Bug document path if applicable ($BUG_DOC)

Note: 如果文档不存在，跳过加载并使用可用上下文继续分发代理。

IF documentation is NOT enabled:

• Skip document loading
• Proceed with agent dispatch

When to Use

digraph when_to_use {
    "Multiple failures?" [shape=diamond];
    "Are they independent?" [shape=diamond];
    "Single agent investigates all" [shape=box];
    "One agent per problem domain" [shape=box];
    "Can they work in parallel?" [shape=diamond];
    "Sequential agents" [shape=box];
    "Parallel dispatch" [shape=box];

    "Multiple failures?" -> "Are they independent?" [label="yes"];
    "Are they independent?" -> "Single agent investigates all" [label="no - related"];
    "Are they independent?" -> "Can they work in parallel?" [label="yes"];
    "Can they work in parallel?" -> "Parallel dispatch" [label="yes"];
    "Can they work in parallel?" -> "Sequential agents" [label="no - shared state"];
}

Use when:

• 3+ test files failing with different root causes
• Multiple subsystems broken independently
• Each problem can be understood without context from others
• No shared state between investigations

Don't use when:

• Failures are related (fix one might fix others)
• Need to understand full system state
• Agents would interfere with each other

The Pattern

1. Identify Independent Domains

Group failures by what's broken:

• File A tests: Tool approval flow
• File B tests: Batch completion behavior
• File C tests: Abort functionality

Each domain is independent - fixing tool approval doesn't affect abort tests.

2. Create Focused Agent Tasks

Each agent gets:

• Specific scope: One test file or subsystem
• Clear goal: Make these tests pass
• Constraints: Don't change other code
• Expected output: Summary of what you found and fixed

3. Dispatch in Parallel

Dispatch helper 1: "Fix agent-tool-abort.test.ts failures"
Dispatch helper 2: "Fix batch-completion-behavior.test.ts failures"
Dispatch helper 3: "Fix tool-approval-race-conditions.test.ts failures"
All three run concurrently in hosts that support parallel helpers/agents.

• In Claude Code: use parallel Task/subagent dispatch
• In Codex: use multiple spawn_agent calls
• In hosts without helper-agent support: investigate sequentially, but keep the scopes separate

4. Review and Integrate

When agents return:

• Read each summary
• Verify fixes don't conflict
• Run full test suite
• Integrate all changes

4.5. Update Task Document (汇总进度)

After all agents complete:

IF .horspowers-config.yaml exists AND documentation.enabled: true:

IF $TASK_DOC is set:

# Update task document with parallel agent results
node -e "
const fs = require('fs');
const taskDoc = process.env.TASK_DOC;
if (fs.existsSync(taskDoc)) {
    let content = fs.readFileSync(taskDoc, 'utf8');
    const timestamp = new Date().toISOString().slice(0, 10);

    const results = [
        { agent: 'Agent 1', result: 'Fixed X' },
        { agent: 'Agent 2', result: 'Fixed Y' },
        { agent: 'Agent 3', result: 'Fixed Z' }
    ];

    let summary = \`- \${timestamp}: 并行代理执行完成\\n\`;
    results.forEach(r => {
        summary += \`  - \${r.agent}: \${r.result}\\n\`;
    });

    if (content.includes('## 进展记录')) {
        content = content.replace(
            /(## 进展记录\\n[\\s\\S]*?)(?=\\n##|\\Z)/,
            '\$1\\n' + summary
        );
    }

    fs.writeFileSync(taskDoc, content);
}
"

Agent Prompt Structure

Good agent prompts are:

1. Focused - One clear problem domain
2. Self-contained - All context needed to understand the problem
3. Specific about output - What should the agent return?

Fix the 3 failing tests in src/agents/agent-tool-abort.test.ts:

1. "should abort tool with partial output capture" - expects 'interrupted at' in message
2. "should handle mixed completed and aborted tools" - fast tool aborted instead of completed
3. "should properly track pendingToolCount" - expects 3 results but gets 0

These are timing/race condition issues. Your task:

1. Read the test file and understand what each test verifies
2. Identify root cause - timing issues or actual bugs?
3. Fix by:
   - Replacing arbitrary timeouts with event-based waiting
   - Fixing bugs in abort implementation if found
   - Adjusting test expectations if testing changed behavior

Do NOT just increase timeouts - find the real issue.

Return: Summary of what you found and what you fixed.

Common Mistakes

❌ Too broad: "Fix all the tests" - agent gets lost ✅ Specific: "Fix agent-tool-abort.test.ts" - focused scope

❌ No context: "Fix the race condition" - agent doesn't know where ✅ Context: Paste the error messages and test names

❌ No constraints: Agent might refactor everything ✅ Constraints: "Do NOT change production code" or "Fix tests only"

❌ Vague output: "Fix it" - you don't know what changed ✅ Specific: "Return summary of root cause and changes"

When NOT to Use

Related failures: Fixing one might fix others - investigate together first Need full context: Understanding requires seeing entire system Exploratory debugging: You don't know what's broken yet Shared state: Agents would interfere (editing same files, using same resources)

Real Example from Session

Scenario: 6 test failures across 3 files after major refactoring

Failures:

• agent-tool-abort.test.ts: 3 failures (timing issues)
• batch-completion-behavior.test.ts: 2 failures (tools not executing)
• tool-approval-race-conditions.test.ts: 1 failure (execution count = 0)

Decision: Independent domains - abort logic separate from batch completion separate from race conditions

Dispatch:

Agent 1 → Fix agent-tool-abort.test.ts
Agent 2 → Fix batch-completion-behavior.test.ts
Agent 3 → Fix tool-approval-race-conditions.test.ts

Results:

• Agent 1: Replaced timeouts with event-based waiting
• Agent 2: Fixed event structure bug (threadId in wrong place)
• Agent 3: Added wait for async tool execution to complete

Integration: All fixes independent, no conflicts, full suite green

Time saved: 3 problems solved in parallel vs sequentially

Key Benefits

1. Parallelization - Multiple investigations happen simultaneously
2. Focus - Each agent has narrow scope, less context to track
3. Independence - Agents don't interfere with each other
4. Speed - 3 problems solved in time of 1

Verification

After agents return:

1. Review each summary - Understand what changed
2. Check for conflicts - Did agents edit same code?
3. Run full suite - Verify all fixes work together
4. Spot check - Agents can make systematic errors

Real-World Impact

From debugging session (2025-10-03):

• 6 failures across 3 files
• 3 agents dispatched in parallel
• All investigations completed concurrently
• All fixes integrated successfully
• Zero conflicts between agent changes