classifier.dev docs MCP server

classifier.dev

Zero-shot text classification. Plain text in, a label and a calibrated confidence out. No key, no signup. Up to a thousand texts per request.

curl https://classifier.dev/spam,not+spam/Win+a+free+iPhone spam

curl "https://classifier.dev/?labels=spam,not+spam&text=Win+a+free+iPhone" # same call, query form spam

Single Cloudflare Worker. No database, no framework, no build step beyond esbuild.

CLI

npm i -g classifier-dev classify bug,feature,praise < feedback.txt

cli/ is a separate npm package (classifier-dev, bin classify): one dependency-free Node file, tests against a mock API (npm test), semver with its own CHANGELOG, released with npm run release patch|minor|major which tags cli-v and lets .github/workflows/publish-cli.yml publish (needs an NPM_TOKEN repo secret). It talks to the API exactly like curl does.

Layout

src/index.ts routing, validation, tiers, LLM fallback chain, analytics src/query.ts the GET query form, read and written with nuqs; the URL an error suggests src/jev.ts TypeSafe's Jev: packs inputs into requests, reads probabilities src/limiter.ts Durable Object: per-IP rate limiting src/report.ts digest — Analytics Engine SQL -> Resend, flags model fallbacks src/alerts.ts every 15 minutes; emails only when something is wrong src/feedback.ts agent feedback, feedback.now protocol -> email src/privacy.ts keyed pseudonyms: nothing kept points back at a caller src/cost.ts per-request upstream spend, from the providers' own accounting src/docs.ts the site (GET / and GET /benchmark), plain text src/home.ts the same two documents rendered, for browsers only src/ui.ts the shared look: markdown in a terminal cli/ the classify command, published to npm as classifier-dev eval/ benchmarks; read eval/README.md before quoting a number finish-dns.sh one-shot DNS wiring, see below wrangler.example.toml the Worker config, minus the account-specific ids

The site

curl classifier.dev prints plain text, exactly as it always has. A browser sends Accept: text/html and gets the same document rendered — headings, bracketed links, copy buttons — from src/home.ts. Nothing is duplicated: the page is generated from DOCS and BENCHMARK at request time, so the text stays canonical and the two cannot drift. ?format=text opts out by hand, and both responses carry Vary: accept.

Agent feedback

Implements the feedback.now protocol (schema 1.1), so any agent that speaks it can report a problem without being told how:

GET /.well-known/agent-feedback.json what this host accepts GET /api/v1/policy categories, severities, limits POST /api/v1/feedback full structured report POST /api/v1/observations lighter signal POST /api/v1/feedback/{id}/attachments more evidence, later GET /api/v1/receipts/{id} did it land, and was it any good

Accepted submissions are emailed to REPORT_TO. Reports are kept in KV for 90 days. A repeat of the same domain + surface + category + title is stored and acknowledged as a duplicate but not emailed again, so one looping agent cannot empty itself into the inbox; the hourly budget is 100 per IP and the remainder comes back on every receipt.

quality_score is a deterministic function of how complete the report is — an agent can read the rule and write a better one next time. Nothing here calls the classifier or Analytics Engine: this is where reports arrive saying those are broken, so it must work when they do not.

Deploy

Shortened. The full README is on GitHub.