The Gate

Deployment layer: The-Gate-VPS runs this engine in production as a multi-tenant MCP server, exposing evaluation as agent-callable tools.

Docs: PRD · Changelog

An editorial quality gate API. Submit a draft and a brief; receive a machine-readable verdict with a scored rubric, evidence quotes, and specific revision instructions. Fixed eight-criterion evaluation — the model cannot freestyle.

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Verdicts

Every evaluation returns one of four outcomes:

Verdict	Meaning
APPROVED	Meets the bar. Publish or pass forward.
APPROVED_WITH_NOTES	Passes with documented weaknesses — review the gaps before publishing.
REVISE	Fails one or more criteria. revision_instructions is populated. Send back to the writer.
BLOCKED	Hard failure. Do not publish. Fabrication, severe brief mismatch, or fundamental structural problem.

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Evaluation structure

Every response includes:

• Scorecard — each criterion scored 1–5 with an assessment and a verbatim quote from the draft as evidence
• Strengths — what's working and why
• Gaps — what's missing or weak, with specifics
• Revision instructions — populated only on REVISE / BLOCKED; tells the writer exactly what to fix
• Confidence score — how certain the model is about the verdict

Universal criteria (all modes)

Criterion	What it checks
context_grounding	No invented facts or sources not in the brief
brief_fidelity	Answers what was asked — format, audience, scope, length
completeness	No placeholders, no [TBD], no trailing sections
internal_consistency	No contradictions in claims, tone, or structure
specificity	Concrete and evidence-backed, not generic

Modes

Apply domain-specific criteria on top of the universal five:

Mode	Additional criteria
content	voice_compliance, structural_quality, factual_integrity
strategy	strategic_alignment, actionability, audience_calibration
technical	technical_accuracy, reproducibility, safety_completeness
communication	tone_appropriateness, clarity, call_to_action

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API

Base URL: /api

Authentication

Gate evaluations and review history — Bearer token:

Authorization: Bearer gate_sk_<prefix>_<secret>

Key management — Admin secret header:

X-Admin-Secret: <GATE_ADMIN_SECRET>

Core endpoints

POST /api/gate                  Run an evaluation
GET  /api/gate/reviews          List reviews for the authenticated key
GET  /api/gate/reviews/:id      Get a single review by UUID

POST   /api/gate/keys           Create an API key
GET    /api/gate/keys           List all keys
DELETE /api/gate/keys/:prefix   Revoke a key

GET  /api/healthz               Health check (no auth)

Request — POST /api/gate

{
  "draft": "string (required, 1–50000 chars)",
  "brief": "string (required, 1–5000 chars)",
  "voice_guide": "string (optional, max 10000 chars)",
  "mode": "content | strategy | technical | communication (default: content)"
}

Response

{
  "id": "uuid",
  "verdict": "APPROVED | APPROVED_WITH_NOTES | REVISE | BLOCKED",
  "confidence": 0.0,
  "weighted_score": 1.0,
  "criteria_results": {
    "<criterion>": {
      "pass": true,
      "score": 1,
      "assessment": "string",
      "evidence": "verbatim quote from the draft"
    }
  },
  "strengths": ["string"],
  "gaps": ["string"],
  "revision_instructions": "string | null",
  "missing_context": "string | null",
  "meta": {
    "mode": "content",
    "draft_hash": "string",
    "has_voice_guide": false,
    "rate_limit": { "used": 1, "limit": 100, "reset_at": "ISO 8601" }
  }
}

Full OpenAPI 3.1.0 spec: lib/api-spec/openapi.yaml

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Stack

Layer	Technology
Runtime	Node.js 24
Framework	Express 5
ORM	Drizzle ORM
Database	PostgreSQL
AI	Anthropic claude-sonnet via AI Integrations
Build	esbuild (single-file bundle)
Language	TypeScript (strict)

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Running locally

pnpm install
pnpm --filter @workspace/db run push     # push DB schema on first run
pnpm --filter @workspace/api-server run dev

Server starts on $PORT (default 8080 in dev).

Environment variables

Variable	Description
GATE_ADMIN_SECRET	Required for all key management endpoints
ANTHROPIC_API_KEY	Anthropic API key
DATABASE_URL	PostgreSQL connection string
PORT	Server port

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Self-hosting

The API is plain Node.js/Express with no platform-specific runtime dependencies. Deploy configs for Railway, Render, and VPS are included (railway.json, render.yaml, DEPLOY-VPS.md). Build output is a single bundled .mjs file.

pnpm run build   # bundles to dist/index.mjs
pnpm run start   # node --enable-source-maps ./dist/index.mjs

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Contact: signalstudio.io · editorial.operating.system@gmail.com