Helloaigent Subscriber MCP Server

@helloaigent-dev/subscriber

The Hello Aigent reference subscriber — an MCP server that lets any agent subscribe to any Hello Aigent feed, fetch signed updates, verify them, and act on them. Plus watch mode: a standing poller that collects verified updates into a digest between agent runs.

npx @helloaigent-dev/subscriber            # MCP server (stdio)
npx @helloaigent-dev/subscriber watch      # standing watcher (default cadence: daily)

WebMCP (browser)

The in-tab on-ramp for ChatGPT’s built-in browser and Chrome (chrome://flags/#enable-webmcp-testing). The page registers three tools (hello_aigent_check_feed, hello_aigent_subscribe, hello_aigent_fetch_updates) so an agent can use the feed without installing MCP. One classic script tag — no build step, no API key.

<script src="/webmcp/hello-aigent-webmcp.js"></script>

Live demo: https://helloaigent.dev. This repo is the public source. Details, judge test steps, and CORS notes: webmcp/README.md.

Tools

Watch mode

npx @helloaigent-dev/subscriber watch --once            # one pass (what schedulers call)
npx @helloaigent-dev/subscriber watch --every 6h        # long-running loop (floor: hourly)
npx @helloaigent-dev/subscriber watch --once --exec "my-agent-cmd"   # trigger a run on new updates

Each pass polls every active subscription, verifies signatures, and appends new updates to the digest file. The server-side mailbox means a missed run loses nothing. --exec runs your command when new updates land, with HELLO_AIGENT_NEW_UPDATES and HELLO_AIGENT_DIGEST set.

Policy

Written to ~/.hello-aigent/policy.json on first run — everything automatic by default, and this file is where you change that:

Feeds nobody reads decay: after 30 idle days watch stops polling them; after 60 it unsubscribes (noted in the digest). Reading the digest or fetching a feed keeps it alive.

Guarantees

• Signature verification before anything is actionable. Envelopes are Ed25519-verified (RFC 8785 JCS canonicalization) against the feed's discovery public key. Anything that fails verification is returned under unverified with its actions stripped.
• Consent is standing policy. Subscribing records principal + consent_scope; your policy file is the consent layer, and unsubscribe is always one idempotent call.
• Local state only. Subscriptions (including bearer tokens), policy, and the digest live in ~/.hello-aigent/ (mode 0600). Override with HELLO_AIGENT_STATE / HELLO_AIGENT_POLICY / HELLO_AIGENT_DIGEST.

MCP client config

{
  "mcpServers": {
    "hello-aigent": { "command": "npx", "args": ["@helloaigent-dev/subscriber"] }
  }
}

Cursor / Grok Bot plugin

This repo is also packaged as an Agent Plugins bundle (MCP + skill) that Cursor and Grok Bot can load. Cursor Marketplace plugins are that same format — there is no separate Grok Bot package. This plugin is not listed on the Cursor Marketplace yet.

1. Custom MCP connector (works today)

Point any MCP client, including Cursor, at the published npm package:

{
  "mcpServers": {
    "hello-aigent": { "command": "npx", "args": ["-y", "@helloaigent-dev/subscriber"] }
  }
}

No API key. Then in chat: ask the agent to subscribe to a feed (try https://helloaigent.dev).

2. Local plugin (MCP + skill)

To load the skill and MCP together while developing:

mkdir -p ~/.cursor/plugins/local
ln -s /path/to/helloaigent-subscriber ~/.cursor/plugins/local/hello-aigent

Restart Cursor, or run Developer: Reload Window. Confirm the Hello Aigent skill and MCP server appear under Customize. Grok Bot uses the same plugin files.

Layout:

3. Official marketplace listing (later)

When this is submitted and approved, install from the Cursor Marketplace. Until then, use the custom connector or the local plugin path above. Do not submit from this README — maintainers will submit at cursor.com/marketplace/publish when ready.

License

MIT