Model Context Protocol (MCP) Server: io.github.akillam/helloaigent-subscriber

The MCP server io.github.akillam/helloaigent-subscriber lets you subscribe your agent to Hello Aigent feeds. It supports workflows to discover feed content, fetch signed updates, verify those updates, and then act based on the verified results.

🛠️ Key Features

Subscribe an agent to Hello Aigent feeds
Discover feed items
Fetch signed updates
Verify fetched updates
Act on verified updates

🚀 Use Cases

Integrating an agent with Hello Aigent feed sources
Building update pipelines that require signed data and verification
Automating agent actions after feed update validation

⚡ Developer Benefits

Clear separation of steps: discover → fetch signed updates → verify → act
Designed for agent-driven processing of Hello Aigent feeds

⚠️ Limitations

Available information does not list specific tools, endpoints, authentication details, or configuration options.

@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.

bash

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

Tools

Tool	What it does
`hello_aigent_subscribe(discovery_url, feed_id?, principal?, consent_scope?)`	Reads the site's `/.well-known/hello-aigent.json`, subscribes (defaults come from your policy)
`hello_aigent_fetch(subscription_id?, max?)`	Pulls only-new-since updates via the stored cursor; verifies every envelope signature
`hello_aigent_unsubscribe(subscription_id)`	Revokes consent (idempotent) — the one-call undo
`hello_aigent_list_subscriptions()`	Lists stored subscriptions (tokens are never exposed)
`hello_aigent_check_site(url)`	Checks a site you're visiting for a feed; auto-subscribes per your standing policy (`origin: auto`)
`hello_aigent_digest()`	Returns unread digest entries collected by `watch` and marks them surfaced
`hello_aigent_setup_watch(cadence?)`	Emits ready-to-apply standing-schedule recipes (scheduled task, recurring task, cron)

Watch mode

bash

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:

Key	Default	Meaning
`principal`	`user@host`	Your stable identity across all feeds — set it once (e.g. your email)
`auto_subscribe`	`on`	Subscribe when your agent visits a Hello Aigent site: `on` / `ask` / `off`
`watch_cadence`	`daily`	How often watch polls (`hourly` floor)
`act`	`safe`	What the agent may do unprompted: `none` / `safe` (side-effect-free) / `thresholds`
`pseudonymous`	`false`	Opt-in: per-site pseudonymous principals

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

json

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

License

MIT

io.github.akillam/helloaigent-subscriber