jevmod

Moderation for communities and apps: every message gets a probability for spam, scam, harassment, nsfw, off-topic, self-harm, doxxing, sexual content involving minors, and for rules you write in plain English. You set the thresholds and the actions. Every decision is logged with its numbers.

It runs on Jev, TypeSafe's System One model: you ask yes/no questions about a message and get probabilities back, no text generation. About $0.04 per 1,000 messages with all categories on.

Site: https://jevmod.dev (community owners) and https://jevmod.dev/developers/ (packages, API, MCP, benchmark, cost calculator)

$ jevmod check "FREE NITRO for the first 100!! claim at discord-gifts.ru/nitro"
scam 0.99      'FREE NITRO for the first 100!! claim at discord-gifts.ru/nitro'  [scam 0.99, spam 0.98, harassment 0.02]

Flag-only by default: nothing is deleted until you turn that on. Fails open: if Jev is unreachable, messages are left alone and the failure is logged. Self-harm is flag-only by design so a moderator can reach out.

On the benchmark (2,531 messages from OpenAI's moderation eval, Jigsaw and YouTube spam) jevmod had the best AUROC in every category it was compared on in OpenAI's human-labelled set: harassment 0.93 and sexual 0.98 against Llama Guard 3 8B, ShieldGemma 2B and toxic-bert; self-harm 0.99 and minors 0.98 against Llama Guard, the only other system with those labels. Calibration was measured too; caveats are in the same file.

The key, once

Every surface needs a TypeSafe API key (free tier at console.typesafe.ai).

pip install "jevmod[keys]"
jevmod init          # asks for the key without echo, verifies it with one call, stores it in the OS keyring

Resolution order everywhere (CLI, API, bots, MCP, Moderator): TYPESAFE_API_KEY in the environment, then the keyring, then a .env in the current directory. In a container or a headless server jevmod init --env-file writes .env with mode 600. jevmod init --forget removes the keyring entry (pip uninstall does not). Keys never go into git; .env is ignored.

Run the bot

Discord

1. Developer Portal → New Application → Bot → Reset Token → enable Message Content Intent (the only privileged intent used).
2. OAuth2 → URL Generator → scopes bot + applications.commands; permissions: Read Messages, Send Messages, Manage Messages, Moderate Members, Manage Channels, Embed Links, Add Reactions. Open the URL, add it to your server.
3. pip install "jevmod[discord]", set DISCORD_TOKEN, run jevmod discord.

The bot creates a private #jevmod-log channel and starts flagging there.

React ❌ on a log entry to mark a false positive (that category's threshold goes up a notch), ✅ to confirm a correct call (down a notch, floor 0.5).

Telegram and Reddit

Telegram: @BotFather → /newbot, make the bot a group admin, pip install "jevmod[telegram]", set TELEGRAM_TOKEN, run jevmod telegram. Admin commands: /mod_status, /mod_set, /mod_rule, /mod_topic, /mod_log.

Reddit: for your own subreddit with your own "script" app credentials, non-commercial (Reddit's API terms). pip install "jevmod[reddit]", fill the REDDIT_* variables from .env.example, run jevmod reddit. Reports by default; removal and bans are opt-in.

What the bots send where

Only the message text and the channel topic go to TypeSafe. Author names and ids never do. Locally, jevmod keeps a decision log (category, probabilities, action, first 300 characters); rows older than 30 days are purged on every batch. /mod forget deletes everything; leaving the server does the same. Members whose message is removed get a direct message saying an automated system did it and how to appeal.

Developer

CLI

pip install jevmod
jevmod check "some text"                                   # exit 0 clean, 1 something triggered, 2 error
cat comments.txt | jevmod check --json --rule "No politics. Game news is fine." -

One message per line on stdin, one Jev request per 50. --topic turns on the off-topic check, --threshold sets one for every category, --json prints one object per line with every probability. examples/cli/ has a file screener and a pre-commit hook.

Python

from jevmod import Moderator, Policy

d = Moderator().check("FREE NITRO for the first 100!! claim at discord-gifts.ru/nitro", channel_topic="gaming")
d.action, d.category, d.probability  # ('flag', 'scam', 0.99)
d.scores  # {'spam': 0.98, 'scam': 0.99, 'harassment': 0.02, 'nsfw': 0.01, ...}

p = Policy()
p.set_category("scam", "delete", 0.7)
p.set_rule("no_politics", "No political discussion. Game news is fine.", action="flag", threshold=0.8)
Moderator(policy=p).check_many(["...", "..."], channel_topic="support")  # one request for the batch

npm

import { Moderator, Policy } from "jevmod";
const d = await new Moderator().check("FREE NITRO ...", { channelTopic: "gaming" });
d.action, d.category, d.scores            // same shape as Python and the HTTP API

Node 20+. Same questions (jevmod/categories.json is copied byte for byte and CI fails if it drifts), same policy, same decision. JevmodClient talks to a deployed HTTP API instead, so browsers and edge functions never hold the TypeSafe key. Express middleware in packages/jevmod-js/examples/. Details in packages/jevmod-js/README.md.

HTTP API

JEVMOD_ADMIN_TOKEN=... jevmod api                     # binds 127.0.0.1; JEVMOD_HOST=0.0.0.0 to expose (Docker does)
curl -X POST localhost:8080/v1/keys -H "Authorization: Bearer $JEVMOD_ADMIN_TOKEN" \
     -H "Content-Type: application/json" -d '{"tenant":"my-app"}'          # {"api_key":"jm_...", shown once}
curl -X POST localhost:8080/v1/moderate -H "Authorization: Bearer jm_..." -H "Content-Type: application/json" \
     -d '{"messages":[{"id":"a","text":"FREE NITRO for the first 100!! claim at discord-gifts.ru/nitro"}]}'

OpenAPI at /docs on a running server (a static copy at docs/openapi.json), a Postman collection at postman/jevmod.postman_collection.json. Any chatbot, forum or comment system that can make an HTTP call can use it; the bots are adapters over the same service.

Examples, one folder per surface

Agents

MCP server. pip install "jevmod[mcp]" then jevmod mcp (stdio). Tools: moderate(texts, channel_topic?, rules?) returns one decision per text; categories() describes each category and its default threshold.

claude mcp add jevmod -- jevmod mcp                                   # Claude Code
{"mcpServers": {"jevmod": {"command": "jevmod", "args": ["mcp"]}}}    # Cursor, Codex, others

Claude Code plugin. This repository is its own marketplace:

/plugin marketplace add ohernandezdev/jevmod
/plugin install jevmod@jevmod

jevmod-integrate adds moderation to an existing codebase (detects the stack, picks SDK/npm/HTTP/MCP, wires the key, inserts the call where it belongs, adds a real test). jevmod-moderate screens text or datasets from the terminal while working. AGENTS.md has every signature; docs/llms.txt indexes the docs.

Categories

Every check returns all enabled categories at once, in one request. The questions are in jevmod/categories.json: one yes/no question per category with explicit true/false criteria, the pattern of TypeSafe's guardrails cookbook. Jev's probabilities move about ±0.03 between runs, so anything within that band of a threshold will flip; the ❌/✅ feedback and PUT /v1/policy exist to move the line.

How it works

Message → pre-filter (trusted authors, under eight letters without a link, repeats of judged text never reach Jev) → batch for 2 s per community → one Jev request for the batch → probabilities → policy → action → audit log. Batched messages are sent as a dict keyed by position; as a list, probabilities leaked between neighbours, which the 98-message adversarial red team caught and which now runs as a regression suite in CI. More in docs/diagrams/ and PLAN.md.

Self-host

One image, one variable picks the role: api, discord, telegram, reddit. SQLite on a volume.

cp .env.example .env && docker compose up -d              # API on :8080
docker compose --profile discord up -d                    # add the Discord bot

A $4/month VM, Fly.io or Railway with a volume is enough. Failure policy: Jev unreachable → decisions come back reason="error_open" and nothing is acted on. There is no quota by default; JEVMOD_MONTHLY_QUOTA=5000 pauses judging for a tenant after 5,000 judged messages in a month as a cost guard, tells the owner once, deletes nothing.

Public demo

The landing page's live check talks to jevmod demo, a separate role that keeps the key on the server and stops at a monthly budget (JEVMOD_DEMO_BUDGET_USD, default $0.50), with per-visitor limits and a CORS allow-list. It logs what visitors try (text, scores, hashed IP) for the operator. deploy/demo/ has a Caddy + Docker compose for a small VPS with HTTPS in two commands.

Development

git clone https://github.com/ohernandezdev/jevmod && cd jevmod
python -m venv .venv && .venv/bin/pip install -e ".[all,dev,examples]"      # Windows: .venv\Scripts\pip
ruff check . && mypy jevmod && pytest          # offline tests run without a key; the rest hit the real API
cd packages/jevmod-js && npm ci && npm test    # same for the npm package

Tests never mock Jev. tests/test_redteam.py is the adversarial regression set; benchmark/ reproduces BENCHMARK.md.

License

MIT, © Omar Hernandez. See DISCLAIMER.md: decisions are probabilistic, the operator owns the thresholds, the actions and legal compliance; not affiliated with TypeSafe, Discord, Telegram or Reddit.