Errata

Name: Errata
Author: formachines-ai

by formachines-aiversion 0.1.2i★ –iRuns on your computer

Registry nameai.formachines/errata

Install

Overview

Description from the maker (original English)

Sandbox-verified fixes where AI models write outdated code for PyPI and npm libraries

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: ERRATA_BASE_URL, ERRATA_TIMEOUT_MS, ERRATA_NO_TELEMETRY

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "errata": {
      "command": "npx",
      "args": [
        "-y",
        "@formachines/errata-mcp"
      ],
      "env": {
        "ERRATA_BASE_URL": "your-value",
        "ERRATA_TIMEOUT_MS": "your-value",
        "ERRATA_NO_TELEMETRY": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add errata --env ERRATA_BASE_URL=your-value --env ERRATA_TIMEOUT_MS=your-value --env ERRATA_NO_TELEMETRY=your-value -- npx -y @formachines/errata-mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "errata": {
      "command": "npx",
      "args": [
        "-y",
        "@formachines/errata-mcp"
      ],
      "env": {
        "ERRATA_BASE_URL": "your-value",
        "ERRATA_TIMEOUT_MS": "your-value",
        "ERRATA_NO_TELEMETRY": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "errata": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@formachines/errata-mcp"
      ],
      "env": {
        "ERRATA_BASE_URL": "your-value",
        "ERRATA_TIMEOUT_MS": "your-value",
        "ERRATA_NO_TELEMETRY": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

ERRATA_BASE_URL env
Base URL of the Errata site (default https://formachines.ai)
ERRATA_TIMEOUT_MS env
Timeout of one request to the base, in milliseconds (default 8000)
ERRATA_NO_TELEMETRY env
Set to 1 to stop sending search misses (error type and scrubbed message) when search_error finds nothing

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026

✓ Pass
Maker matches the repo
The registry name was verified against the domain formachines.ai (the registry checks domain ownership)
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 32455 servers in this category
Published to the registry more recently than 89% of the other 32455 servers in this category
Basic checks equal to or better than 100% of the other 32455 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Errata safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.2) reached the registry 4 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, SSTracker free youth training

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

Spec Driven Development

by formulahendry

MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.

Runs on your computer★ 440MITUpdated 14 months ago

Install

Remote Desktop Commander

by desktop-commander

Remote Desktop Commander: use files, terminal and processes on your own computers from any AI app.

Runs in the cloud★ 211Updated yesterday

Install

SSTracker free youth training

by sstracker.app

Free youth sports drills, practice plans and age-group answers for parents and coaches.

Runs in the cloudUpdated today

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

@formachines/errata-mcp

An MCP server for Errata: places where AI models write outdated code for PyPI and npm libraries, each with a fix verified in a sandbox. Three tools; stdio; no API key.

Install

Claude Code:

claude mcp add errata -- npx -y @formachines/errata-mcp

Any client with a JSON config (Claude Desktop, Cursor, Windsurf, VS Code …):

"mcpServers": { "errata": { "command": "npx", "args": ["-y", "@formachines/errata-mcp"] } } }

Node 20 or newer. Registry name: ai.formachines/errata.

Tools

tool	input	answer `status`
`check_package`	`ecosystem` (`pypi`/`npm`), `package`, `version` (exact, or a range; may be omitted)	`found` · `unconfirmed_version` · `not_affected` · `no_coverage` · `technical_error`
`search_error`	`text`: an error line, a traceback, or an entry id	`found` · `candidates` · `no_match` · `technical_error`
`report`	`id`, `verdict` (`confirm`/`dispute`), `note` (≤ 500 characters)	`received` · `merged` · `withdrawn` · `unknown_entry` · `invalid` · `rejected` · `technical_error`

Each entry in an answer carries verdict (apply / lead / none), grade (verified / possible / not_affected / unknown), reason, wrong, right, detect, error, fails_on, verified_on, url.

Example, check_package {"ecosystem":"pypi","package":"click","version":"8.5.0"} against the live base:

{"status":"found","package":"pypi/click","installed":"8.5.0","entries":[{"id":"pypi/click/8.5.0/0001","verdict":"apply","grade":"verified","reason":"checked on click 8.5.0; installed 8.5.0; proof.auto_apply true","symbol":"click.Parameter","wrong":"parameter = click.Parameter([\"--x\"])","right":"parameter = click.Option([\"--x\"])","detect":["click.Parameter"],"error":"Can't instantiate abstract class Parameter with abstract methods _parse_decls, add_to_parser","fails_on":"8.5.0","verified_on":["8.5.0"],"url":"https://formachines.ai/errata/pypi/click/0001-click-parameter/"}]}

and the same package at a version nobody checked, "version":"8.6.0": status: "unconfirmed_version", verdict lead, reason *installed 8.6.0 is newer than the versions checked (8.5.0); one checked version is not a range*.

Rule

One rule for the server, the CLI, the skill and the site (printed in every page footer, llms.txt and the JSON agent_rule): apply a correction on your own only when the installed version is one it was checked on (versions.checked_on: fails_on and every recheck) and its proof.auto_apply is true. A newer version than the checked ones, one between works_on and fails_on, or an unknown one is lead; works_on or older is none.

Merged and withdrawn entries are never offered: answers list them under not_offered with the entry that carries a merged one now. report refuses them before sending. An unreachable base is technical_error with isError: true, never no_coverage.

Environment

variable	default
`ERRATA_BASE_URL`	`https://formachines.ai`
`ERRATA_FEEDBACK_URL`	`/v1/feedback`
`ERRATA_TIMEOUT_MS`	`8000` per request
`ERRATA_CACHE_TTL_S`	`600` (in-process cache: one index and changelog per ten minutes)
`ERRATA_LOG_LEVEL`	`warn` (logs go to stderr; the text of `search_error` is never logged)
`ERRATA_NO_TELEMETRY`	unset; `1` (or `DO_NOT_TRACK=1`) stops the search-miss report below

Requests carry the User-Agent formachines-errata-mcp/ , so the site counts MCP traffic apart.

Search misses (since 0.1.2). When search_error finds nothing, the server sends POST https://formachines.ai/v1/miss with the source (mcp), the exception type and its message scrubbed of paths, numbers, IP addresses, hex, UUIDs, e-mails, token-like strings and quoted values other than plain names ('numpy' stays, 'my secret' becomes ), at most 200 characters. A dotted type keeps only its last part (acme.errors.BillingError → BillingError). No code, no project name, no other lines of the traceback; text with no SomeError: … line sends nothing. It is sent in the background (the answer never waits for it, a network error is ignored) and only on a miss. The receiver scrubs again, keeps no IP address and uses the list to decide which errors to cover next. ERRATA_NO_TELEMETRY=1 turns it off.

Overhead

Measured 2026-11-02 against formachines.ai: the first check_package costs 3 requests (index 5.9 kB, changelog 31 kB, the package JSON 5–12 kB), later calls in the next ten minutes only the package JSON (or nothing, when cached). search_error costs one 31 kB request for the error index. Sizes are uncompressed; since 2026-11-02 the site sends JSON gzipped, about a fifth of that on the wire. Answers are compact: 0.6 kB for click, 1.9 kB for typescript (two entries), 0.9 kB for a matched error.

What the server does not promise

Not a full scan. The base covers a few dozen packages; no_coverage means no corrections, not that the code is current.
No range proof. One checked version is not a range; newer versions are lead.
Not an applier. The server never edits code; apply says the base allows applying the fix as is.
Reports are not published. report sends to a quarantine that is rechecked in the sandbox before anything changes; a note is never shown to other agents.
No offline mode. Without the network every tool answers technical_error.

Check it yourself

npx -y @modelcontextprotocol/inspector --cli npx -y @formachines/errata-mcp --method tools/list

Development

npm install

npm test npm run typecheck npm pack

src/core is shared with errata-cli and kept identical in both. Tests run against a snapshot of formachines.ai/errata in test/fixtures/site (2026-11-02); npm test starts the built server over stdio with the SDK client and runs the seven acceptance cases; scripts/inspect-live.sh repeats them with MCP Inspector against the live base. server.json follows the registry schema 2025-12-11.

MIT licence. The data is CC BY 4.0 (formachines.ai/errata).

Errata

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

SSTracker free youth training

README from the maker

@formachines/errata-mcp

Install

Tools

Rule

Environment

Overhead

What the server does not promise

Check it yourself

Development