{
  "schema_version": "newruntime-agent-readable-v0.1",
  "type": "trend_pattern",
  "slug": "harness-architecture-outlives-model-choice",
  "title": "Harness architecture outlives model choice",
  "description": "Rules, tools, permissions, memory, evaluation, execution, and recovery are becoming a stable runtime layer while models remain replaceable components.",
  "thesis": "For production agents, the harness is becoming a more durable product boundary than the identity of the model running inside it.",
  "status": "published",
  "confidence": "high",
  "first_seen": "2026-06-28",
  "last_verified": "2026-07-16",
  "supporting_signals": [
    "tg-2708",
    "tg-2692",
    "tg-2678",
    "tg-2582",
    "tg-2567",
    "tg-2607"
  ],
  "related_posts": [
    "agent-api-design",
    "claude-code-subagents-memory",
    "hilos-development-control-plane"
  ],
  "counter_evidence": [
    "Provider-native harnesses can exploit proprietary model behavior and product features that portable runtimes cannot reproduce.",
    "Model changes still alter tool use, planning, latency, and safety enough that switching is not operationally free."
  ],
  "revision_trigger": "Revise the thesis if model-provider coupling consistently produces better reliability and lower total migration cost than portable rules, tools, traces, and execution contracts.",
  "topics": [
    "harness-engineering",
    "agent-runtime",
    "model-routing"
  ],
  "source_urls": [
    "https://opencode.ai/docs/models",
    "https://github.com/NousResearch/hermes-agent",
    "https://github.com/langchain-ai/deepagents",
    "https://github.com/rivet-dev/agentos",
    "https://docs.inference.net/introduction"
  ],
  "routes": {
    "html": "https://newruntime.com/patterns/harness-architecture-outlives-model-choice/",
    "markdown": "https://newruntime.com/patterns/harness-architecture-outlives-model-choice.md",
    "json": "https://newruntime.com/patterns/harness-architecture-outlives-model-choice.json"
  },
  "source_format": "markdown"
}