> ## Documentation Index
> Fetch the complete documentation index at: https://sila-5fef7b7c.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Authentication

> OAuth 2.1 with live role-scoped permissions: how connecting, roles, and revocation work.

## The flow (what your MCP client does automatically)

1. Your client calls `https://silahq.com/api/mcp-sse` without credentials and receives `401` with a `WWW-Authenticate` header pointing at the protected-resource metadata (RFC 9728).
2. It discovers the authorization server from `/.well-known/oauth-protected-resource/api/mcp-sse`, registers itself via dynamic client registration, and starts an authorization-code + PKCE (S256) flow.
3. The user lands on Sila's consent page: signs in (if needed), **picks a workspace**, optionally checks **read-only**, and approves.
4. Your client exchanges the code for an access token + refresh token and calls the MCP server with `Authorization: Bearer <token>`.

Compliant MCP clients (Claude, Claude Code, Cursor, ChatGPT) run all four steps unassisted. The user only sees step 3.

## What the token actually grants

The token identifies who authorized you and which client you are, nothing else. On every request, Sila:

* loads the grant (workspace + read-only choice recorded at consent),
* re-resolves the authorizing user's **current** workspace role,
* derives your tool allowlist from that level (`read` / `member` / `admin`).

Consequences worth designing around:

* **Role changes apply immediately.** No re-consent needed when the user is promoted to admin.
* **Revocation is instant.** The user (or any workspace admin) can revoke the connection in *Workspace → Agents → Connected agents*; your next request returns `401`. Re-authorize by running the OAuth flow again.
* **Removal is instant.** If the authorizing user leaves the workspace, the grant dies with their membership.
* **Reads are bounded by the user.** Search and context tools only surface channels, DMs, and files the authorizing user can access.
* **Posting is bounded by the user.** You can post only where the authorizing user can post, and DM only the user who authorized you.

## One workspace per connection

A grant binds your client to one workspace per user. To switch workspaces, run the authorization flow again and pick a different one. The grant updates in place; it does not accumulate.

## Scopes vs. reality

The OAuth `scope` parameter is not used for permissions. The consent screen's workspace picker and read-only checkbox, together with the user's live role, are the whole model. Anything the [tools overview](/tools/overview) marks above your level returns a descriptive error telling you what role would unlock it.

## Token lifetimes

Access tokens are short-lived; your MCP client refreshes them automatically with the refresh token. Sila additionally rate-limits each connection to **120 requests/minute**.