Proposal: Bio-inspired routing, resilience, and discovery strategies

## Summary

We've implemented 6 bio-inspired communication strategies in [openclaw-a2a-gateway](https://github.com/win4r/openclaw-a2a-gateway) (TypeScript, 475 tests), adapting mathematical models from cell biology to improve A2A agent communication. The results show measurable improvements across routing accuracy, fault recovery, discovery efficiency, and backpressure signaling.

We'd like to explore contributing some of these as optional, pluggable strategies to the official SDK.

## What we built

Each feature maps a well-established biological mechanism to an A2A communication pattern:

| Feature | Biological Model | A2A Application | Key Result |
|---------|-----------------|-----------------|------------|
| Hill equation routing | Ligand-receptor affinity (Hill 1910) | Affinity-scored agent matching | Routing accuracy 20% → 70% |
| 4-state circuit breaker | Receptor desensitization (phosphorylation → internalization → recycling) | Gradual degradation instead of binary open/close | +25% requests served during recovery |
| Signal decay notifications | cAMP enzymatic degradation | Priority-weighted retry with automatic cleanup | Delivery rate 42% → 88% |
| Quorum sensing discovery | Bacterial quorum sensing (AHL threshold) | Density-aware polling frequency | 55% fewer discovery queries |
| Adaptive transport selection | Cellular signal pathway selection | Success rate × latency scoring per transport | Automatic failover + recovery |
| Michaelis-Menten concurrency | Enzyme kinetics saturation curve | Progressive backpressure instead of hard rejection | Smooth degradation under load |

All features are backward-compatible — without bio config, behavior is identical to standard A2A.

## How these map to SDK extensibility points

Based on our reading of the SDK's architecture:

| Feature | SDK Interface | Approach |
|---------|--------------|----------|
| **Adaptive transport** | `TransportFactory` | Custom factory that wraps default transports with per-transport success/latency tracking, reorders by composite score |
| **Quorum sensing discovery** | `AgentCardResolver` | Wrapper that adjusts polling frequency based on discovered peer density (hysteresis thresholds prevent oscillation) |
| **4-state circuit breaker** | `CallInterceptor.before` | Interceptor that tracks failure counts per peer, returns early with degraded capacity in desensitized state |
| Hill routing | Needs new interface | Affinity scoring requires a routing/dispatch strategy abstraction |
| MM concurrency | Server middleware | Pre-execution delay based on load ratio |
| Signal decay | Push notification extension | Importance weighting on notification retry |

The first three (adaptive transport, QS discovery, 4-state CB) align with existing interfaces and could be contributed without modifying core SDK types.

## Benchmark methodology

Pure logic simulation testing production code paths. 22 test cases across 6 dimensions. Full benchmark: [`tests/benchmark.test.ts`](https://github.com/win4r/openclaw-a2a-gateway/blob/master/tests/benchmark.test.ts)

## Proposed contribution path

1. Start with **adaptive transport selection** as a reference `TransportFactory` implementation (highest interface fit, smallest diff)
2. Follow with QS discovery and 4-state CB as optional strategies
3. For features needing new interfaces (Hill routing, MM concurrency), discuss API design here first

## References

- Hill, A.V. (1910) "The possible effects of the aggregation of the molecules of haemoglobin on its dissociation curves." J Physiol 40:iv-vii
- Michaelis, L. & Menten, M.L. (1913) "Die Kinetik der Invertinwirkung." Biochem Z 49:333-369
- Tan, Y. & Slotine, J.J. (2013) "A quorum sensing inspired algorithm for distributed clustering." MIT
- Vishwakarma, R. (2025) "Bio-Inspired Multi-Agent Communication" (prior art — concept-only, no implementation)

Happy to discuss any of these in more detail. We'd love to contribute back to the ecosystem.

openclaw-a2a-gateway リポジトリを調査し、6つの生物模倣戦略とその TypeScript 実装を理解します。SDK に既に存在する `TransportFactory`、`AgentCardResolver`、`CallInterceptor.before` インターフェースを調べ、提案された機能をどのように統合できるかを確認します。まず、成功率とレイテンシーの追跡機能でデフォルトのトランスポートをラップする新しい `TransportFactory` として、適応型トランスポート選択を実装します。

索引モデルが issue の本文から書いたものです。