Add multi-agent race condition test (bd-zo7o)

- Created test_agent_race.py with 3 test scenarios
- Tests collision prevention with Agent Mail reservations
- Validates that only one agent claims an issue when reservations active
- Demonstrates collision problem when Agent Mail disabled
- Includes stress test with 10 agents
- Non-interactive mode support for CI/automation

Amp-Thread-ID: https://ampcode.com/threads/T-2fb10899-490f-4d41-b003-8bc4d467cc54
Co-authored-by: Amp <amp@ampcode.com>

examples/python-agent/agent.py

@@ -8,19 +8,34 @@ This demonstrates how an agent can:
 3. Discover new issues during work
 4. Link discoveries back to parent tasks
 5. Complete work and move on
+6. Coordinate with other agents via Agent Mail (optional)
 """
 
 import json
 import subprocess
 import sys
+import os
+from pathlib import Path
 from typing import Optional
 
+# Add lib directory to path for beads_mail_adapter
+lib_path = Path(__file__).parent.parent.parent / "lib"
+sys.path.insert(0, str(lib_path))
+
+from beads_mail_adapter import AgentMailAdapter
+
 
 class BeadsAgent:
     """Simple agent that manages tasks using bd."""
 
     def __init__(self):
         self.current_task = None
+        self.mail = AgentMailAdapter()
+        
+        if self.mail.enabled:
+            print(f"📬 Agent Mail enabled (agent: {self.mail.agent_name})")
+        else:
+            print("📭 Agent Mail disabled (Beads-only mode)")
 
     def run_bd(self, *args) -> dict:
         """Run bd command and parse JSON output."""
@@ -32,7 +47,20 @@ class BeadsAgent:
         return {}
 
     def find_ready_work(self) -> Optional[dict]:
-        """Find the highest priority ready work."""
+        """Find the highest priority ready work.
+        
+        Integration Point 1: Check inbox before finding work.
+        """
+        # Check inbox for notifications from other agents
+        messages = self.mail.check_inbox()
+        if messages:
+            print(f"📨 Received {len(messages)} messages:")
+            for msg in messages:
+                event_type = msg.get("event_type", "unknown")
+                payload = msg.get("payload", {})
+                from_agent = msg.get("from_agent", "unknown")
+                print(f"   • {event_type} from {from_agent}: {payload}")
+        
         ready = self.run_bd("ready", "--limit", "1")
 
         if isinstance(ready, list) and len(ready) > 0:
@@ -40,9 +68,27 @@ class BeadsAgent:
         return None
 
     def claim_task(self, issue_id: str) -> dict:
-        """Claim a task by setting status to in_progress."""
+        """Claim a task by setting status to in_progress.
+        
+        Integration Point 2: Reserve issue before claiming.
+        Integration Point 3: Notify other agents of status change.
+        """
+        # Reserve the issue to prevent conflicts with other agents
+        if not self.mail.reserve_issue(issue_id):
+            print(f"⚠️  Failed to reserve {issue_id} - already claimed by another agent")
+            return {}
+        
         print(f"📋 Claiming task: {issue_id}")
-        return self.run_bd("update", issue_id, "--status", "in_progress")
+        result = self.run_bd("update", issue_id, "--status", "in_progress")
+        
+        # Notify other agents of status change
+        self.mail.notify("status_changed", {
+            "issue_id": issue_id,
+            "status": "in_progress",
+            "agent": self.mail.agent_name
+        })
+        
+        return result
 
     def create_issue(self, title: str, description: str = "",
                      priority: int = 2, issue_type: str = "task") -> dict:
@@ -62,9 +108,24 @@ class BeadsAgent:
         )
 
     def complete_task(self, issue_id: str, reason: str = "Completed"):
-        """Mark task as complete."""
+        """Mark task as complete.
+        
+        Integration Point 4: Release reservation and notify completion.
+        """
         print(f"✅ Completing task: {issue_id} - {reason}")
-        return self.run_bd("close", issue_id, "--reason", reason)
+        result = self.run_bd("close", issue_id, "--reason", reason)
+        
+        # Notify other agents of completion
+        self.mail.notify("issue_completed", {
+            "issue_id": issue_id,
+            "reason": reason,
+            "agent": self.mail.agent_name
+        })
+        
+        # Release the reservation
+        self.mail.release_issue(issue_id)
+        
+        return result
 
     def simulate_work(self, issue: dict) -> bool:
         """Simulate doing work on an issue.