# Connect to Firehose
Open Firehose on the computer where you installed it, or from your phone or another computer. Then check that your agent can start a session.
This page describes Firehose 1.0.1.
## Before you begin
You need a Firehose installation that you have [installed](/getting-started/install/) and [activated](/getting-started/activate/). Firehose runs on your own computer: your repositories and agents stay there, and your browser is how you work with them.
You also need an agent command-line tool, such as Claude Code or Codex, installed and signed in on that computer.
## Open Firehose on your computer
Open `http://localhost:4801` in a browser on the computer running Firehose. If you installed with `--port`, use that port instead.
Your projects and sessions appear once the page loads. If you see **Activate Firehose**, finish [activation](/getting-started/activate/) first.
This address works only on that computer. Another device on your home or office network cannot open it, even with the computer's IP address.
## Open Firehose from your other devices
To use Firehose from your phone or another computer, turn on tailnet access. It uses [Tailscale](https://tailscale.com/download), a private network between your own devices, and serves Firehose over HTTPS with a certificate from Tailscale.
**Only you can connect this way.** Firehose answers only the Tailscale account that owns the computer. Anyone else who opens the address sees `This Firehose only answers its owner over the tailnet.`
### Set up Tailscale
Tailscale connects your own devices to each other over a private network, called a tailnet. Every device you use with Firehose needs Tailscale installed and signed in to the same Tailscale account. You set this up once.
1. On the Firehose computer, install Tailscale from [tailscale.com/download](https://tailscale.com/download):
- **macOS:** download the app, or get it from the Mac App Store. Open it and sign in.
- **Linux:** run the install script, then connect the computer and follow the sign-in instructions:
```sh
curl -fsSL https://tailscale.com/install.sh | sh
sudo tailscale up
```
2. On your phone or other computer, install Tailscale from the same page and sign in with the same account.
3. Check that MagicDNS is on. It is on by default for tailnets created on or after October 20, 2022. Otherwise, open the [DNS page](https://console.tailscale.com/admin/dns) of the Tailscale admin console and select **Enable MagicDNS**.
4. On the same DNS page, under **HTTPS Certificates**, select **Enable HTTPS**. Firehose needs it to serve your address over HTTPS.
Enabling HTTPS publishes your computer names and your tailnet's DNS name on a public certificate ledger. Tailscale asks you to acknowledge this before it turns HTTPS on.
For other platforms and details, see Tailscale's [installation guide](https://tailscale.com/kb/1347/installation) and [Enabling HTTPS](https://tailscale.com/kb/1153/enabling-https).
### Turn on tailnet access
With Tailscale running on the Firehose computer, use one of these:
- **During installation:** answer `y` when the installer asks to open Firehose from your other devices, or install with `--tailnet`.
- **In the terminal:** run `firehose tailnet on`.
- **In the dashboard:** open **Settings** (the gear icon at the bottom of the icon rail on the far left). Under **Open from your other devices**, turn on **Allow my other devices**. If Settings says **Restart Firehose to apply this.**, select **Restart now**.
When it is on, Firehose shows the address to use. It looks like `https://your-computer.your-tailnet.ts.net:4801`, where `your-computer.your-tailnet.ts.net` is a placeholder for your computer's full Tailscale name. Under **Open from your other devices** in **Settings**, select **Copy** to copy it.
Open from your other devices in Settings, turned on. The address is a placeholder; yours uses your computer's Tailscale name.
If Settings says **Install Tailscale and sign in to use this.** or **Turn on MagicDNS for your tailnet in the Tailscale admin console.**, fix that in Tailscale first. MagicDNS gives your computer the `.ts.net` name the address uses.
### Connect from the other device
1. Install Tailscale on the other device and sign in with the same Tailscale account.
2. Open the address Firehose showed you.
3. Check that your projects and sessions appear.
You can also open **agents.okthink.ai**, the hosted Firehose app, and enter your computer's full Tailscale name:
1. In the **Connect to Firehose** dialog, enter the name in **Server address**, such as `your-computer.your-tailnet.ts.net`, without `https://` or a port.
2. Select **Save and connect**.
The hosted app always connects on port 4801. If you installed Firehose on another port, open the address shown under **Open from your other devices** in **Settings** directly instead.
A short computer name or a Tailscale IP address does not work in the hosted app. Use the full name ending in `.ts.net` so it matches the HTTPS certificate.
To turn tailnet access off, run `firehose tailnet off` or turn off **Allow my other devices**.
## Check that your provider is ready
Select **New session**, the **+** button at the top right of the **Sessions** sidebar. In the **New agent session** dialog, confirm that your project appears at **Pick a project**, choose its workspace, and select the provider you installed. Its model choices should load. After you choose an available model and check permissions, **Start session** should open a session in that workspace.
Choose an agent. Model choices depend on your provider and account. Sample project.
These are three separate checks: project discovery, model discovery, and session startup. A model list alone does not prove the provider can handle your account’s requests. Complete the [small explanation task](/getting-started/first-session/#4-give-it-a-clear-request) to check an actual response.
If a check fails, note the project name, provider, selected model, exact error, and the last step that worked. See [startup troubleshooting](/troubleshooting/common-problems/#start-session-is-unavailable-or-fails).
## Use more than one server
In the hosted app, each browser tab chooses its own server. Reloading a tab keeps its selected address. You can connect another tab to a different server.
To switch servers, open **Settings** (the gear icon at the bottom of the icon rail on the far left). Under **Server connection**, enter the other server's address and select **Save and connect**. Switching preserves the previous server’s stored workspace for when you return.
**Forget this server** clears that server’s stored workspace, including drafts, annotations, open files, and project ordering. Use switching when you intend to return; read the confirmation before forgetting a server.
## If you can’t connect
On the Firehose computer, run `firehose status` to check that Firehose is running. From another device, check that the Firehose computer is awake and that both devices are signed in to the same Tailscale account. Follow [connection troubleshooting](/troubleshooting/common-problems/#i-cant-connect-to-my-server) for the next checks.
Once connected, [start your first session](/getting-started/first-session/).
