docs: add capacity planning section to README

README.md

@@ -32,6 +32,29 @@ This means your focus shifts from doing to overseeing — reviewing PRs, not wri
 
 See [Architecture](./docs/kugetsu-architecture.md) for full system design and phase status.
 
+## Capacity Planning
+
+Based on parallel capacity testing (`tools/parallel-capacity-test/`):
+
+| Resource | Value |
+|----------|-------|
+| **Memory per agent** | ~340 MB |
+| **Recommended max agents** | 5 |
+| **Timeout threshold** | 8+ agents |
+| **Memory limit** | 1 GB per agent (configurable) |
+
+### Observed Behavior
+
+- **1-5 agents**: 100% success rate, ~6-9s avg response time
+- **8+ agents**: Timeouts occur due to resource contention
+- Scaling is roughly linear up to 5 agents
+
+### Recommendations
+
+1. **Limit max parallel agents to 5** for stable operation
+2. **Monitor memory usage** when scaling beyond 3 agents
+3. **Configure memory limit** via `--memory-limit` flag based on available RAM
+
 ## Documentation
 
 - [Architecture](./docs/kugetsu-architecture.md) — Full system design