用 Jev 实现 LLM 模型路由：候选模型、约束与回退

// Node.js 20+. Save as jev-example.mjs and run: node jev-example.mjs
// Set OMNIAKEY_API_KEY in the server/terminal environment first.
const key = process.env.OMNIAKEY_API_KEY;
if (!key) throw new Error("Set OMNIAKEY_API_KEY before running.");

const body = {
  "model": "jev-latest",
  "state": {
    "task": "Review a complex customer dispute with 100k context and tool use",
    "candidates": [
      {
        "id": "fast-model",
        "description": "Fast general model with 32k context",
        "cost": "low",
        "latency": "low"
      },
      {
        "id": "reasoning-model",
        "description": "Strong reasoning, 200k context, and tool use",
        "cost": "high",
        "latency": "medium"
      }
    ],
    "priorities": [
      "quality",
      "context",
      "tool_use",
      "cost"
    ],
    "constraints": [
      "Customer data must remain within approved tools"
    ],
    "stakes": "high"
  },
  "questions": {
    "model": {
      "type": "choice",
      "instructions": "Select the best approved candidate using the stated quality, context, tools, cost, latency, and stakes. Do not assume undocumented capabilities. Choose escalate when no candidate is adequate or evidence is insufficient.",
      "criteria": {
        "fast-model": "Choose this approved model if its documented capabilities satisfy the task, priorities, constraints, and stakes: {\"id\":\"fast-model\",\"description\":\"Fast general model with 32k context\",\"cost\":\"low\",\"latency\":\"low\"}",
        "reasoning-model": "Choose this approved model if its documented capabilities satisfy the task, priorities, constraints, and stakes: {\"id\":\"reasoning-model\",\"description\":\"Strong reasoning, 200k context, and tool use\",\"cost\":\"high\",\"latency\":\"medium\"}",
        "escalate": "No approved candidate can safely satisfy the task, or the provided evidence is insufficient to select one."
      }
    }
  }
};

const response = await fetch("https://api.omniakey.com/v1/alpha/search", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${key}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify(body),
  signal: AbortSignal.timeout(25_000),
});
if (!response.ok) {
  const retryAfter = response.headers.get("retry-after");
  throw new Error(`Jev HTTP ${response.status}; Retry-After: ${retryAfter ?? "not supplied"}`);
}
const result = await response.json();
console.log(JSON.stringify(result, null, 2));
// Inspect and validate the answer before connecting it to any external action.