ALTWEB Context Loader

Name: ALTWEB Context Loader
Author: danielsoimu

by danielsoimuversion 1.1.2i★ –iRuns on your computer

Registry namesoftware.altweb/altweb-context

Install

Overview

Description from the maker (original English)

Loads signed ALTWEB context capsules — refuses unsigned, tampered, or untrusted by default.

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: ALTWEB_TRUST_FILE

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": {
    "altweb-context": {
      "command": "npx",
      "args": [
        "-y",
        "altweb-context"
      ],
      "env": {
        "ALTWEB_TRUST_FILE": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add altweb-context --env ALTWEB_TRUST_FILE=your-value -- npx -y altweb-context

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": {
    "altweb-context": {
      "command": "npx",
      "args": [
        "-y",
        "altweb-context"
      ],
      "env": {
        "ALTWEB_TRUST_FILE": "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": {
    "altweb-context": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "altweb-context"
      ],
      "env": {
        "ALTWEB_TRUST_FILE": "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

ALTWEB_TRUST_FILE env
Override the local trust file of allowed signer public keys (default: ~/.altweb/trusted-keys.json). A missing or empty trust file refuses every capsule.

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 altweb.software (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 32415 servers in this category
Published to the registry more recently than 62% of the other 32415 servers in this category
Basic checks equal to or better than 100% of the other 32415 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 ALTWEB Context Loader 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 (1.1.2) reached the registry 24 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, Safe Fetch

Alternatives

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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.

ALTWEB — signed context capsules

Signed context capsules for AI agents — Markdown compiled into self-contained, verifiable, optionally encrypted artifacts + an MCP loader that refuses unsigned or untrusted context. Verify before you inject.

AI agents run on plain-text context: instructions, personas, skills, memory files. None of it has provenance — anything that can write those files can poison them. ALTWEB gives context a chain of custody, and makes the loader refuse anything that lacks one:

Capsule — markdown compiled into a single .altweb.html file (or URL): content compressed (deflate), optionally encrypted (AES-256-GCM), optionally signed (ECDSA P-256). Self-contained — opens in any browser, verifies offline, needs no server: you hand someone a file, not a database.
Verified context loading — the altweb-context MCP server loads a capsule into your agent *only* when the signature is valid and the signer's public key is in your trust file. Unsigned, tampered, or untrusted capsules are refused at load time, with an explicit reason. Refusal is the default: an empty trust file rejects everything, signed or not.

you write MD ──► altweb compile --sign ──► capsule (.altweb.html / URL)

│ agent asks for context ──► altweb-context ──► verify signature + trust │ trusted ──► markdown injected everything else ──► REFUSED (reason)

Packages

Package	What it is
`altweb`	CLI: `altweb compile / decode / verify / keygen` (`packages/cli`)
`altweb-context`	MCP server: `load_capsule`, `verify_capsule`, `list_trusted_keys` (`packages/mcp`)
`@altweb/core`	Headless engine: content model, codec, crypto, markdown, sanitize (bundled into both; npm release planned)
`@altweb/editor`	Notion-style editor (built on Novel) with one-click capsule export
`site/`	Documentation site (Astro + Starlight)

Quickstart

Both tools are on npm — nothing to clone. Run these commands outside a source checkout (inside this repository, npm resolves the local workspace package):

# create your signing identity (deterministic from a passphrase; only the

public key + fingerprint are stored, in ~/.altweb/identity.json)

npx altweb keygen --save

write, compile, sign

echo "# My agent's operating notes" > notes.md npx altweb compile notes.md -o notes.altweb.html --sign

verify anywhere, offline

npx altweb verify notes.altweb.html

Wire the loader into an MCP client (Claude Code example):

claude mcp add altweb-context -- npx -y altweb-context

(From source: npm install && npm run build, then use the bundles under packages/*/dist/.)

Running from source

Node.js 20 or newer is required. From the repository root:

npm install

npm run build

Create and save an identity with the locally built CLI

npm run keygen

Start the editor in development mode

npm run dev

The editor prints its local URL (normally http://localhost:5173). The CLI can be invoked as node packages/cli/dist/altweb.mjs . Do not use npx altweb inside the checkout: npm may select the local workspace package, whose executable does not exist until it has been built.

The documentation site is intentionally a separate npm project rather than a workspace. To run it locally:

npm install --prefix site

npm run dev --prefix site

Trust a signer by adding its full public key to ~/.altweb/trusted-keys.json (the UNTRUSTED_KEY refusal message hands you the ready-made entry; the short fingerprint is a human label, not the trust anchor):

{ "keys": [ { "name": "Me", "publicKey": "<base64url SPKI>", "fingerprint": "ab:12:..." } ] }

What a signature proves — and what it does not

A valid signature proves who authored the capsule and that the bytes are intact. It does not make the content safe or true. The trust file is your policy; keep it short.

Pick a long passphrase. Identities derive deterministically from your passphrase via Argon2id with a fixed protocol salt (that is what makes them portable with nothing stored). Memory-hardness makes mass dictionary attacks economically hostile, but the passphrase's entropy is still the identity's foundation. Use a 16+ character diceware-style phrase; the tooling enforces a minimum strength.

Security

Content is sanitized with DOMPurify on decode; artifacts carry a CSP; the codec validates structure with zod. See site/ docs → Security model for the full write-up, including the encrypted-capsule caveat (the signature covers the decrypted payload, so verification completes after decryption).

Roadmap

Near-term, in rough order:

`@altweb/core` on npm — the engine as an installable library, for programmatic use (the CLI and loader already ship it bundled).
Hardware-backed identity (FIDO2 / passkeys) — an *optional* identity type alongside the passphrase one: the private key lives in a security key or secure enclave, never extractable, signing requires physical presence. The passphrase identity stays the default — "a passphrase is a keypair" — hardware keys add *something you have* for those who want it.

Credits

Built on excellent open source: Novel (Apache-2.0) and Tiptap (MIT) for the editor; DOMPurify, marked, pako, zod, @noble/curves in the engine. See NOTICE.

License

ALTWEB is dual-licensed:

Open source: [AGPL-3.0-or-later](./LICENSE). Free to use, study, modify, and share — with one core obligation: if you modify ALTWEB and distribute it or run it as a network service (e.g. hosting altweb-context for others), you must release your modified source under the AGPL.
Commercial: by agreement. To use ALTWEB in a closed-source product, or as a hosted service without publishing your changes, you need a separate commercial license. See COMMERCIAL.md.

ALTWEB Context Loader

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

Safe Fetch

README from the maker

ALTWEB — signed context capsules

Packages

Quickstart

public key + fingerprint are stored, in ~/.altweb/identity.json)

write, compile, sign

verify anywhere, offline

Running from source

Create and save an identity with the locally built CLI

Start the editor in development mode

What a signature proves — and what it does not

Security

Roadmap

Credits

License