MCP

Inline MCP lets MCP-compatible clients use your Inline workspace with explicit OAuth consent.

Use it when you want assistants to read conversations, find context, create threads, and send text/media in approved spaces.

Status

Alpha (first-cohort release). Stable enough for early production usage; surface may evolve.

Quick Setup

ChatGPT Apps

Add an MCP connector in ChatGPT Apps.
Set server URL to https://mcp.inline.chat/mcp.
Complete Inline OAuth sign-in and consent.

Claude

claude mcp add --transport http inline https://mcp.inline.chat/mcp

Then complete Inline OAuth sign-in in Claude.

Other Clients

Use these values for any remote MCP client with OAuth 2.1 + PKCE:

Server URL: https://mcp.inline.chat/mcp
OAuth metadata: https://api.inline.chat/.well-known/oauth-authorization-server
Protected resource metadata: https://mcp.inline.chat/.well-known/oauth-protected-resource

Compatibility: https://mcp.inline.chat/oauth/* is proxied to the Inline OAuth server.

Tools

Current MCP tools are grouped around agent workflows instead of raw API endpoints:

account.me: inspect the current authorization, granted scopes, and allowed chat context.
spaces.list: list spaces visible to the current grant.
people.search: resolve people by name, username, or user ID in allowed contexts.
conversations.list: list recent conversations or resolve a conversation by name/title/ID.
conversations.get: inspect one resolved chat or DM, including participants and pinned message IDs.
conversations.create: create a new conversation in an allowed space or home threads.
messages.list: list recent messages in one chat or DM with filters (since, until, content, etc).
messages.context: fetch a before/after window around a message ID, or latest compact context.
messages.search: search messages in one chat or DM (not global search).
messages.unread: list unread messages across approved conversations.
messages.send: send a text message to a chat or DM.
files.upload: upload media from base64 or an HTTPS URL and get Inline media IDs.
files.get: extract file/media metadata from specific message IDs or recent messages.
messages.send_media: send uploaded photo/video/document with optional caption.
messages.send_batch: send ordered text/media items in one call.

Legacy tools search and fetch are removed.

Entity URIs

Chat, message, and person entities include a canonical uri field using Inline deep links:

inline://chat/{chatId}
inline://chat/{chatId}/message/{messageId}
inline://user/{userId}

Use IDs for tool calls. Use uri when showing, storing, or handing links back to a user.

Common Workflows

Inspect the current grant: account.me.
Resolve a target: spaces.list or people.search, then conversations.list, then conversations.get.
Summarize a thread: messages.list with since/until, then summarize in the model.
Read around a found message: messages.search or messages.unread, then messages.context.
Find links/media/files: messages.search with content: "links" | "media" | "files", or files.get for concrete file metadata.
Create a thread then post: conversations.create, then messages.send.
Send media: files.upload, then messages.send_media.
Import a compact batch: conversations.create, then messages.send_batch.

Configuration

Authorization flow:

Client performs dynamic OAuth registration.
User signs in to Inline.
User grants scopes and chooses allowed spaces.
Client exchanges the authorization code with PKCE (S256).

Scopes:

messages:read
messages:write
spaces:read
offline_access

Default scope: messages:read spaces:read

Access tokens last 1 hour. Refresh tokens last 30 days and are issued only when offline_access is requested.

Permissions

Space access is limited to spaces selected during consent.
DM access is available only if DMs is enabled.
Home-thread access is available only if Home threads is enabled.
Tool scopes are enforced on every call.

Limits

messages.list and messages.search: up to 50 messages per call.
messages.unread: up to 200 messages per call.
messages.send_batch: up to 100 items per call.
files.upload: max file size 25 MB.
files.upload URL source: HTTPS only, private/local network targets are blocked, up to 3 redirects.
New MCP session initialization (POST /mcp without mcp-session-id) is rate-limited per IP.
MCP sessions are in-memory and have idle expiry; server restart drops active sessions.
Each active MCP session uses one Inline realtime WebSocket connection.

Agent Compatibility

Tools advertise output schemas, annotations, and _meta.securitySchemes through tools/list.
Tool responses include structured content plus a JSON text fallback for clients that need text content.
Missing read/write scopes return normal MCP tool errors with _meta["mcp/www_authenticate"] so compatible clients can reauthorize without treating the request as a server failure.
Time filters accept natural values such as today, yesterday, 2d ago, YYYY-MM-DD, or epoch seconds.

Troubleshooting

401 invalid_token: reconnect and complete OAuth again.
403 insufficient_scope: reconnect and grant needed scopes.
429 rate_limited: wait and retry initialization.
404 unknown_session: session expired/restarted; reconnect to create a new session.
Missing expected chats: reconnect and expand consent (spaces, DMs, home threads).
No refresh behavior: ensure client requested offline_access.

MCP vs Other Inline APIs

Use MCP for assistant workflows in MCP-native clients.
Use Realtime API for fully custom client/app integrations.
Use Bot API for direct HTTP bot integrations.