Jev MCP server: the judgment layer and the action layer

import { TypeSafeClient, noul, score } from "@typesafe-ai/sdk";

const jev = new TypeSafeClient({ timeout: 4000 });

// One file, reviewable, version controlled. Not spread across prompts.
const QUESTIONS = {
  strength: score(
    "How far will this post travel compared to a typical post from the same author?",
    [
      "Flops. Gets less attention than a typical post from the same account.",
      "Typical. Performs about the same as the account usually does.",
      "Above typical. Noticeably more reach and replies than usual.",
      "Strong. Several times the usual reach. Spreads past the existing audience.",
      "Breakout. Orders of magnitude beyond usual.",
    ]
  ),
  slop: noul(
    "This reads like it was generated by an AI rather than written by a person."
  ),
  toxicity: noul(
    "This text contains slurs, harassment, sexual content, or abuse targeted at a person or group."
  ),
};

const PUBLISH_AT = 2.0;   // score, out of 4
const CONFIDENT_AT = 0.6; // confidence on that score
const SLOP_CEILING = 0.5; // noul, a probability

export async function decide(draft) {
  const { answers } = await jev.systemOne({
    state: { draft_post: draft, platform: "X (Twitter)" },
    questions: QUESTIONS,
  });

  // A Noul returns only `noul`. There is no confidence field on it.
  if (answers.toxicity.noul > 0.2) return { act: "block", why: "toxicity" };
  if (answers.slop.noul > SLOP_CEILING) return { act: "rewrite", why: "reads as AI written" };

  // A Score returns `score` and `confidence`. Both matter for an action this hard to undo.
  if (answers.strength.confidence < CONFIDENT_AT) return { act: "ask_human", why: "low confidence" };
  if (answers.strength.score < PUBLISH_AT) return { act: "rewrite", why: "weak draft" };

  return { act: "publish", score: answers.strength.score };
}

// Only reached when decide() returned "publish".
// The agent calls the MCP tool; the tool is not exposed to the model before this point.
await mcp.callTool("opentweet_create_tweet", {
  text: draft,
  platforms: ["x", "bluesky", "linkedin"],
  publish_now: true,
});