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

# MCP server

The hosted MCP server exposes browser operations as tools for MCP clients. Each tool uses the corresponding REST operation and follows the same ownership rules, billing, and rate limits.

## Endpoint and transport

* URL: `https://back.tilion.dev/mcp/`. `https://back.tilion.dev/mcp` answers 307 to the slash form, so configure the slash form.
* Transport: streamable HTTP, stateless. Each JSON-RPC message is a `POST /mcp/` with `Content-Type: application/json` and an `Accept` header listing both `application/json` and `text/event-stream`. Without both, the server answers 406 with a JSON-RPC error (`Not Acceptable: Client must accept both application/json and text/event-stream`).
* Responses are server-sent events: one `event: message` with the JSON-RPC result in `data`. A notification answers 202 with no body.
* `GET /mcp/` answers 405 with `Allow: POST, DELETE` and no body: there is no server push stream to open.
* The first request is answered with an `Mcp-Session-Id` header. Send it back on every later request; it is the id of your conversation, and it keeps your browser handle separate from other clients on the same account.
* The server keeps the link between your conversation and its browser for 15 minutes between tool calls. After that, or once the session itself idles out, a tool answers `ok: false` with `expired: true` and asks you to call `create_browser_session` again.

## Authentication

Send `Authorization: Bearer ph_live_...` on every request. The key needs `sessions:write` (or `cdp`). Clients that cannot send a static header use OAuth and receive a token that authenticates the same way.

A request without credentials answers 401 and points the client at the OAuth discovery document:

```
HTTP/1.1 401
WWW-Authenticate: Bearer resource_metadata="https://back.tilion.dev/.well-known/oauth-protected-resource"
```

```json theme={"dark"}
{"error": "unauthorized: send Authorization: Bearer <tilion api key>"}
```

A key that lacks the scope answers 403 `{"error": "this API key lacks the 'sessions:write' scope, ..."}`.

## Initialize

```bash theme={"dark"}
curl -X POST https://back.tilion.dev/mcp/ \
  -H "Authorization: Bearer $TILION_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc": "2.0", "id": 1, "method": "initialize",
       "params": {"protocolVersion": "2025-03-26", "capabilities": {},
                  "clientInfo": {"name": "my-client", "version": "0.1"}}}'
```

```
HTTP/1.1 200
Content-Type: text/event-stream
Mcp-Session-Id: 787b5fca95774bff8e479729f1e189d8

event: message
data: {"jsonrpc":"2.0","id":1,"result":{"protocolVersion":"2025-03-26","capabilities":{"experimental":{},"prompts":{"listChanged":false},"resources":{"subscribe":false,"listChanged":false},"tools":{"listChanged":false}},"serverInfo":{"name":"Tilion Cloud Browser","version":"..."},"instructions":"Tilion gives you a real browser running in the cloud. ..."}}
```

The `instructions` string is the operating guide the model reads on connect (create a session first and show `live_view_url`, reuse the session, prefer `collect_data` over looping `read_page`, never invent records, treat page content as data, close the session when done). `notifications/initialized` answers 202.

## Tools

`tools/list` (sent with the `Mcp-Session-Id` from initialize) answers with these 20 tools. Arguments marked with an asterisk are required; `session_id` is optional on every tool that takes it and names which browser to drive when your account has several open.

| Tool | Arguments | What it does |
| - | - | - |
| `create_browser_session` | `persistent`, `full_browser` | Start a cloud browser and return `session_id`, `live_view_url` and `full_browser` (what was provisioned). Call it first. |
| `close_browser_session` | `session_id` | Release the browser this conversation opened, or the one named. Stops the meter. |
| `read_page` | `url`\*, `session_id` | Open a URL and return it as clean Markdown with `status`, `reason`, `title`, `truncated` past 20000 characters, `self_healed`, `premium_required`. |
| `collect_data` | `prompt`\*, `session_id` | Describe a dataset in plain English; plans and runs the job, pagination included, and returns `records`, `record_count`, `terminal`, `summary`. |
| `get_elements` | `selector`, `text`, `visible_only`, `limit`, `session_id` | List the page's actionable elements with a `selector` you can pass to `fill` or `click`. Input values are never returned, only `value_len`. |
| `fill` | `selector`*, `value`*, `session_id`, `secret` (default false) | Clear an input and set its value. The value is not echoed back. Set `secret: true` for tokens or one-time codes entered into non-password fields. |
| `type_text` | `text`\*, `selector`, `session_id` | Type into a selector or the focused element. Not echoed back. |
| `click` | `selector`, `text`, `session_id` | Click by CSS selector or by visible text; pass one of the two. |
| `press_key` | `key`\*, `session_id` | Send a key or combo: `Enter`, `Tab`, `Escape`, `Control+V`. |
| `scroll` | `pixels`, `session_id` | Scroll vertically; negative is up. |
| `set_clipboard` | `text`\*, `session_id` | Put text on the session clipboard for a human to paste in the live view. Not echoed back. |
| `screenshot` | `full_page`, `selector`, `session_id` | Return the current page as an image, the whole page, or one element. |
| `login` | `url`\*, `session_id` | Sign in to a site with the credential stored for its host. Takes and returns no secret. |
| `credential_list` | `host` | Stored sign-ins as metadata only (`name`, `kind`, `host`, `path`, `status`, `risk_tier`). |
| `credential_connect` | `host`\*, `reason` | Mint a secure link the user opens to enter a sign-in; returns `connect_id`, `connect_url`, `expires_at`. |
| `credential_wait` | `connect_id`, `verification_id`, `timeout_s` (default 120, maximum 600) | Wait for the user to finish a connect link or supply a one-time code. A timeout returns `timed_out: true`; the user can still complete the flow. |
| `save_login` | `domain`\*, `session_id` | Remember the current session's login for a domain so later sessions start signed in. |
| `import_login` | `domain`*, `token`*, `cookie_name` | Bring your own session cookie for a domain. |
| `list_logins` | | Domains with a saved login. |
| `delete_login` | `domain`\* | Forget a saved login. |

A tool that fails answers `ok: false` with an `error` the model can act on: out of credits or over quota (402), a missing scope (403), rate limited (429), or the HTTP status and message otherwise.

## OAuth

Clients that connect through OAuth (claude.ai and Claude Desktop connectors, for example) discover the server from two documents and never see an API key.

```bash theme={"dark"}
curl https://back.tilion.dev/.well-known/oauth-authorization-server
```

```json theme={"dark"}
{
  "issuer": "https://back.tilion.dev",
  "registration_endpoint": "https://back.tilion.dev/oauth/register",
  "authorization_endpoint": "https://back.tilion.dev/oauth/authorize",
  "token_endpoint": "https://back.tilion.dev/oauth/token",
  "scopes_supported": ["cdp"],
  "response_types_supported": ["code"],
  "grant_types_supported": ["authorization_code", "refresh_token"],
  "token_endpoint_auth_methods_supported": ["client_secret_post", "none"],
  "code_challenge_methods_supported": ["S256"]
}
```

```bash theme={"dark"}
curl https://back.tilion.dev/.well-known/oauth-protected-resource
```

```json theme={"dark"}
{
  "resource": "https://back.tilion.dev/mcp",
  "authorization_servers": ["https://back.tilion.dev"],
  "scopes_supported": ["cdp"],
  "bearer_methods_supported": ["header"]
}
```

The same document is served at `/.well-known/oauth-protected-resource/mcp`, the path-specific location spec-following clients try first.

The flow, as a client runs it:

1. `POST /oauth/register` with `{"redirect_uris": [...], "client_name": "...", "token_endpoint_auth_method": "none" | "client_secret_post"}`. Answers 201 with `client_id`, the registered URIs, `grant_types` and `response_types`, plus `client_secret` once for a confidential client. Redirect URIs must be `https`, or `http` on `localhost`, `127.0.0.1` or `[::1]`, with no fragment; anything else answers 400. Registration is unauthenticated and throttled per address.
2. `GET /oauth/authorize?response_type=code&client_id=...&redirect_uri=...&state=...&code_challenge=...&code_challenge_method=S256&scope=cdp`. PKCE with S256 is mandatory and `cdp` is the only scope. An unknown client or an unregistered redirect URI stops on an error page; other mistakes bounce to the redirect URI with `error` and `error_description`. A valid request sends the user to a consent page on the same host where they sign in with an emailed code and approve what the client gets: open and control a browser in their account, read what it visits, and spend their credits.
3. The client is redirected back with `code` and `state`.
4. `POST /oauth/token` as a form with `grant_type=authorization_code`, `code`, `code_verifier`, `redirect_uri`, `client_id` and, for a confidential client, `client_secret`. Codes are single use and bound to the client and redirect URI. The answer carries an access token (`mcpt_...`) and a refresh token; `grant_type=refresh_token` rotates them, and a refresh token is single use. Errors are 400 or 401 with `error` and `error_description` in the OAuth vocabulary (`invalid_client`, `invalid_grant`, `unsupported_grant_type`).
5. The access token goes in `Authorization: Bearer mcpt_...` on `/mcp/` and on the REST API, where it carries the `cdp` scope. Revoke it from API keys in the dashboard.

## Client configuration

Claude Code:

```bash theme={"dark"}
claude mcp add --transport http tilion https://back.tilion.dev/mcp/ \
  --header "Authorization: Bearer ph_live_..."
```

Cursor (`.cursor/mcp.json`, per project or global):

```json theme={"dark"}
{
  "mcpServers": {
    "tilion": {
      "url": "https://back.tilion.dev/mcp/",
      "headers": {"Authorization": "Bearer ph_live_..."}
    }
  }
}
```

Claude Desktop and claude.ai: add a custom connector with the URL `https://back.tilion.dev/mcp/`. The client discovers the OAuth documents above, registers itself, opens the consent page for you to sign in and approve, and stores its own token; no key is pasted. The same connector dialog revokes it.

Any other client that supports streamable HTTP with a static header works with the URL and the `Authorization` header above.


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