> ## Documentation Index
> Fetch the complete documentation index at: https://docs.gravitygtm.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Add Horizon to Slack

> Install the Slack app, complete signup, and ask your first question

Horizon's Slack app is the fastest way to use Horizon — no code, no API
key to manage yourself. Ask questions in plain English in a channel, a DM,
or with a slash command, and the same enrichment engine that powers the
REST API and MCP server does the work.

<Tip>
  Building your own agent or workflow instead? See the [Quickstart](/horizon/quickstart)
  for the REST API, or [MCP Install](/horizon/mcp-install) to wire Horizon into
  Claude, Cursor, or another MCP client.
</Tip>

## 1. Install the app

Click **Add to Slack** (your Horizon contact or the product page has the
link) and approve the OAuth consent screen for your workspace. Horizon
requests the bot scopes it needs to reply in channels/DMs, react with a
status emoji, read thread history it's already participating in so
follow-ups work without re-mentioning it, and upload CSV exports for large
result lists — nothing beyond what those features require.

## 2. Complete signup

Right after install, Horizon DMs you:

> 👋 Thanks for installing Horizon! Before I can answer questions, complete
> a quick, free signup (verifies a card on file, no charge): *\[link]*

That link opens a Stripe Checkout page in **setup mode** — it verifies a
card on file to deter abuse of the free trial, but **charges nothing**.
Completing it grants your workspace **200 free credits** and a
confirmation DM arrives:

> 🎉 You're all set! Horizon granted your workspace 200 free credits (200
> available). Just @mention me or use `/usehorizon` with a question — e.g.
> "find John Doe's email at acme.com". Need more later? Buy a pack: *\[link]*

No one in the workspace can ask Horizon a real question until this step is
done — an @mention or `/usehorizon` before signup just re-sends the same
signup link instead of running anything (so nothing is ever billed before
you've completed it).

## 3. Ask your first question

Three ways to talk to Horizon:

* **@mention** it in any channel it's in: `@Horizon find the CEO of Acme Corp`
* **DM** it directly, no @mention needed
* **Slash command**: `/usehorizon find the CEO of Acme Corp`

Horizon replies in a thread under your question (or under the message it
echoes back, for a slash command), with a short progress update if the
request takes a few tool calls, and a final answer that ends with what it
spent — e.g. `_Spent 27 credits · 173 remaining_`.

## Buying more credits

When your free trial runs low, ask Horizon (it'll tell you when you're out)
or DM it any time — every confirmation message includes a direct top-up
link for the next pack. See [Credits & Pricing](/horizon/credits-and-pricing) for
the full pack list; Slack, REST, and MCP all draw from the **same balance**,
so a pack bought from Slack works everywhere else too.

## What's next

See [Using Horizon in Slack](/horizon/slack-usage) for the full rundown — compound
requests, list/batch processing, the spend-confirmation card, and the
free-tier daily limit.