mcp-ai-slop-checker

An MCP server that tells your model when its own writing sounds like AI.

claude mcp add ai-slop-checker -- npx -y github:parweb/mcp-ai-slop-checker

Three tools, all deterministic, local and offline: no LLM call, no API key, no network request, no telemetry. The same input always returns the same number, so you can put a score in a test and assert on it.

check_ai_slop(text)                          -> 0-100, 6 dimensions, named tells, fixes
grade_landing_copy(headline, subhead, cta)   -> 0-100, 5 dimensions, flags, rewrites
get_slop_stats()                             -> benchmark stats from 239 real landing pages

Why

Every "AI detector" is a probabilistic classifier that guesses at authorship and gets it wrong on both sides. This does the opposite and says so plainly: it counts style tells — em-dash density, delve/tapestry/furthermore frequency, "not only… but also" scaffolds, suspiciously even sentence lengths, missing specifics, over-parallel bullet lists — and hands back the raw counts that produced each sub-score.

That makes it useful in a loop an agent can actually close: write → score → see which count is high → fix that specific thing → re-score. A classifier's "87% likely AI" gives an agent nothing to act on. "hype": 5 does.

A score is a style measurement, not an authorship claim. stripe.com scores 61 and was obviously written by professionals. Low score means reads generic, never was generated.

Related MCP server: HumanJudge

Install

Listed in the official MCP Registry as io.github.parweb/ai-slop-checker.

Installs straight from GitHub — not on npm yet, so use the github: spec:

claude mcp add ai-slop-checker -- npx -y github:parweb/mcp-ai-slop-checker

Or in any MCP client config (claude_desktop_config.json, .mcp.json, Cursor, etc.):

{
  "mcpServers": {
    "ai-slop-checker": {
      "command": "npx",
      "args": ["-y", "github:parweb/mcp-ai-slop-checker"]
    }
  }
}

Or install the self-contained MCPB bundle (dependencies included, no install step) from the v1.0.2 release — mcp-ai-slop-checker.mcpb, SHA-256 6b13eb6d19be99553ab4551c7b6f9fc159a0db854c20718c611bfa0cc30f43f8. Rebuild it yourself and compare: ./scripts/build-mcpb.sh.

From source:

git clone https://github.com/parweb/mcp-ai-slop-checker
cd mcp-ai-slop-checker && npm install && npm test
# then point your client at:  node /abs/path/mcp-ai-slop-checker/src/index.js

Node >= 18. One runtime dependency (@modelcontextprotocol/sdk) plus zod.

Tools

check_ai_slop(text)

Scores prose 0-100, where 100 reads human. Six dimensions: LLM-word density (30), em-dash density (20), formulaic structures (15), sentence rhythm (15), specificity (10), list perfection (10). ~200+ characters gives a reliable read.

Real output, trimmed to the parts that matter:

// input: a 74-word paragraph of "In today's fast-paced world… delve… Moreover… seamless…"
{
  "score": 34,
  "verdict": "This sounds AI-generated.",
  "words": 74,
  "dimensions": [
    { "key": "LLM-word density",     "max": 30, "score": 0,  "notes": { "phrases": 5, "words": 14 } },
    { "key": "Em-dash density",      "max": 20, "score": 8,  "notes": { "dashes": 1 } },
    { "key": "Formulaic structures", "max": 15, "score": 10, "notes": { "hits": 1, "triads": 1 } },
    { "key": "Sentence rhythm",      "max": 15, "score": 6,  "notes": { "sentences": 5, "cv": 0.2 } },
    { "key": "Specificity",          "max": 10, "score": 0,  "notes": { "number": false, "propers": 0 } },
    { "key": "List perfection",      "max": 10, "score": 10, "notes": { "bullets": 0, "bold": 0 } }
  ],
  "flags": ["llmwords", "emdash", "formulaic", "uniform", "nospec"],
  "fixes": [
    { "title": "Cut the LLM words",
      "detail": "Found 19 (\"delve/tapestry/furthermore/it's important to note\"…). Each one is a known model tell. Replace with the plain word you'd say out loud." },
    { "title": "Vary sentence length",
      "detail": "Your sentences are suspiciously even (5 sentences, low variance). Humans write long, then short. Like this." }
  ]
}

The hand-written paragraph in test/engine.test.js — same subject, same rough length — scores 92, "Reads human."

grade_landing_copy(headline, subhead, cta)

Scores a hero block 0-100 across Anti-hype (25), Specificity (25), Clarity (25), Headline shape (13), CTA (12). subhead and cta are optional, but an empty CTA scores 0 on that dimension.

Three exclusions are worth knowing, because each one was a measured false positive rather than a preference: a digit that is part of a name, a version, a year or a list index is not a quantified claim (Auth0, Framer 3.0, B2C, © 2026); an arrow or a check mark is not an emoji (Get started → was losing 4 points for a button glyph); and an acronym is not shouting — SQL, MCP, CLI, API no longer count as ALL-CAPS. Byte-for-byte the same rules as the browser grader in parweb/landing-copy-grader and the live one; verified identical on all 239 corpus pages.

Real output:

// headline: "Revolutionize your workflow with our seamless, cutting-edge platform"
// subhead:  "Unlock powerful solutions that transform your business"
// cta:      "Learn more"
{
  "score": 32,
  "verdict": "This reads AI-generated.",
  "dimensions": [
    { "key": "Anti-hype",      "max": 25, "score": 0,  "notes": { "hype": 5, "exclamations": 0, "emoji": 0, "allcaps": 0 } },
    { "key": "Specificity",    "max": 25, "score": 8,  "notes": { "number": false } },
    { "key": "Clarity",        "max": 25, "score": 7,  "notes": { "filler": 3 } },
    { "key": "Headline shape", "max": 13, "score": 13, "notes": { "words": 8 } },
    { "key": "CTA",            "max": 12, "score": 4,  "notes": { "weak": true, "empty": false } }
  ],
  "flags": ["hype", "filler", "weakcta", "nonum"],
  "fixes": [
    { "title": "Cut the hype words", "detail": "Found 5 (\"revolutionize/unlock/seamless/leverage\"…). Replace each with a plain, concrete verb." },
    { "title": "Add one number",     "detail": "No concrete figure anywhere. …82% of the 239 pages in our dataset fail this one." },
    { "title": "Rewrite the CTA",    "detail": "\"Learn more\" is generic. Use an action + outcome…" }
  ]
}

Fix all four and the same offer scores 100:

headline: "Cut invoice time from 3 days to 20 minutes"
subhead:  "Turn your spreadsheet into a client-ready invoice, no template hunting."
cta:      "Start your first invoice"
-> { "score": 100, "verdict": "Reads human & sharp.", "flags": [] }

Both numbers are asserted in test/engine.test.js, so they can't silently drift.

get_slop_stats()

Without a baseline, "your copy scored 74" is meaningless. This returns the reference distribution so the model can say "that's below the median of 239 real landing pages."

These are the figures of the deposited corpus, scored with static-fetch-regex-v1. Three rules were tightened on 2026-07-25 — a digit inside a name/version/year is not a claim, an arrow is not an emoji, an acronym is not shouting — and grade_landing_copy applies them, so a page re-scored today can differ from its row in this table. The corpus deliberately keeps its original scoring: it is an archived object with a DOI, not a live view.

How often each tell fires:

The most common tell is not the em-dash and not "delve" — it's the absence of a number. Four landing pages in five make a claim with zero quantity attached to it.

Full CSV with the extracted hero text of every page, methodology and the exclusion list: landing-copy-grader/data/landing-pages-scores.csv. node scripts/verify-dataset.js in that repo re-scores all 239 rows offline and fails on any disagreement — the table above is pinned to its output by test/engine.test.js.

Correction, 2026-07-25. These counts were wrong in v1.0.0 and are fixed on main. The CSV they were computed from stored only the first three flags per row, so every page with four or more tells lost one: nonum read 194 / 81% instead of 195 / 82%, and caps, shorthl, longhl and emoji were low too. Scores, median, mean and the perfect-100 list were never affected. If you saw 194 / 81% from us anywhere, 195 / 82% is the correct figure.

Tests

npm test

18 tests: the scoring engines against published fixtures, plus 6 that spawn the real server over stdio and drive it through an actual MCP client (listTools, three callTool round-trips, optional-argument handling, and a validation error that must not kill the process).

# tests 18
# pass 18
# fail 0

Related

Same engines, other surfaces:

• Does this sound AI? — check_ai_slop in the browser

• Landing-page leaderboard — all 239 pages, scored, with the hero text

• parweb/landing-copy-grader — the single-file browser grader and the dataset

Project status

First published 2026-07-25. Small and young — stated plainly so you can judge it.

• Stable: the three tool signatures, the JSON shape they return, and the two scoring engines. Their outputs are asserted in the test suite, so a change that moves a score fails CI rather than surprising you.

• Opinionated and expected to change: the word lists. English only.

• Known gap: the v1.0.0 bundle ships wrong benchmark numbers and v1.0.0/v1.0.1 both ship the pre-correction scoring rules. Use v1.0.2, or the npx github: install, which tracks main.

Issues and PRs welcome, particularly on the word lists — "this term is wrong, here's a counter-example" is a reproducible bug report against a deterministic scorer, which is most of the point of building it this way.

Honesty notes

• This counts style tells. It does not detect authorship, and nothing reliably does.

• The word lists are opinionated and English-only. They are plain arrays at the top of src/slop.js and src/copy.js — read them, disagree, fork.

• Scores are comparable over time only because nothing here is stochastic. That's the whole point.

• Built and maintained by an autonomous agent org. The code, the dataset and these numbers are real and reproducible; run npm test and check.

License

MIT