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

# Quickstart

> Resolve a user, publish keys, open an MCP session, and call ask.

Assumes the public relay at `https://relay.fau.run` and a user whose Mac node is
registered.

## 1. Publish your agent keys

Host this JSON at `https://<your-domain>/.well-known/fau-agent` over HTTPS (no redirects
for the node’s fetch):

```json theme={null}
{
  "domain": "assistant.example",
  "keys": [
    {
      "kid": "k1",
      "kty": "OKP",
      "crv": "Ed25519",
      "x": "<base64url of raw 32-byte Ed25519 public key>"
    }
  ]
}
```

`domain` must match the host that serves the document. See [Identity](/agent-docs/agent-docs/connect/identity).

## 2. Resolve the user

```bash theme={null}
curl -sS https://relay.fau.run/v1/resolve \
  -H 'content-type: application/json' \
  -d '{"address":"user@gmail.com"}'
```

```json theme={null}
{
  "relay": "relay.fau.run",
  "hostname": "n….relay.fau.run",
  "box_pubkey": "…",
  "queue_endpoint": "https://relay.fau.run/v1/queue"
}
```

Treat unknown users the same as offline ones — the JSON shape is identical for decoys.
See [Resolve](/agent-docs/agent-docs/connect/resolve).

## 3. Check the node (unsigned)

```bash theme={null}
curl -sS "https://<hostname>/.well-known/fau-node"
```

```json theme={null}
{
  "protocol": "fau/1",
  "node": "<hostname>",
  "auth": "rfc9421+capability",
  "tools": ["ask", "get_upcoming_travel", "…"],
  "served_at": 1760000000
}
```

This GET is **not** signed. If TLS fails, use the [offline queue](/agent-docs/agent-docs/connect/offline-queue)
or retry later — do not treat that as “user does not exist.”

## 4. Open an MCP session (signed)

Every `POST https://<hostname>/mcp` must include RFC 9421 headers
([Signing](/agent-docs/agent-docs/connect/signing)) plus:

```http theme={null}
Content-Type: application/json
Accept: application/json, text/event-stream
```

**Initialize** first:

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "initialize",
  "params": {
    "protocolVersion": "2025-06-18",
    "capabilities": {},
    "clientInfo": { "name": "my-agent", "version": "1.0.0" }
  }
}
```

Then send `notifications/initialized` (signed, no `id`). Preserve any
`mcp-session-id` response header on later calls. See [Transport](/agent-docs/agent-docs/connect/transport).

## 5. Call a tool

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/call",
  "params": {
    "name": "ask",
    "arguments": { "question": "When is my next flight?" }
  }
}
```

First contact usually returns tool JSON with `"error":"approval_required"`, a
`match_code`, and an `approval_id`. Show the **verified domain** and **match code** to
the user, wait for phone approval, then **retry the same `tools/call`** (same args).

You normally do **not** get a capability token back from `/mcp`. After approval the
node stores a grant for your domain; retry signed without inventing a Bearer token.
See [Approvals](/agent-docs/agent-docs/tools/approvals).

## 6. Prefer narrow tools

Structured tools → `ask` → `get_excerpt` only when raw text is explicitly needed.
Catalog: [Tools](/agent-docs/agent-docs/tools/overview).