mcp-tg

README

mcp-tg

MCP server for Telegram Client API (MTProto). Provides 75 tools, 4 resources, 3 prompts, and argument completions for comprehensive Telegram account management.

Uses gotd/td for MTProto protocol — this is a user account client, not a bot.

MCP Protocol Support

Feature	Status
Tools	75 tools with annotations (read-only / idempotent / write / destructive)
Resources	4 (dialogs, profile, chat info, chat messages)
Prompts	3 (reply, summarize, search and reply)
Completions	Peer argument autocompletion from dialogs
Elicitation	Auth flow (phone, code, 2FA password)
Progress	File uploads, media albums, message search
Roots	File path validation for uploads/downloads
Transports	stdio + HTTP/SSE
KeepAlive	30s ping interval
Middleware	Auth guard, request logging

Telegram Protocol Features

• Peer cache — resolved peers with access hashes are cached in memory, so numeric ID lookups reuse valid hashes instead of failing
• Invite links — t.me/+hash and t.me/joinchat/hash are resolved via messages.checkChatInvite
• FLOOD_WAIT retry — automatic sleep and retry (up to 3 times) when Telegram rate-limits the client
• Auth guard — tool calls are blocked with a clear error until Telegram authentication completes
• Pagination — offsetDate for dialog listing, offsetId for message search and history

Tools (75 registered; 64 listed below)

The categorised list below documents 64 of the 75 registered tools — the remaining 11 are wired in cmd/mcp-tg/main.go but have not been written up in this file yet. See the source for the full surface area.

Messages (11)

• tg_messages_list — List messages in a chat
• tg_messages_get — Get specific messages by ID
• tg_messages_context — Get messages around a specific message
• tg_messages_search — Search messages in a chat
• tg_messages_send — Send a text message
• tg_messages_edit — Edit an existing message
• tg_messages_delete — Delete messages
• tg_messages_forward — Forward messages between chats
• tg_messages_pin — Pin or unpin a message
• tg_messages_react — Add or remove reactions
• tg_messages_mark_read — Mark messages as read

Dialogs (3)

• tg_dialogs_list — List all dialogs
• tg_dialogs_search — Search dialogs by query
• tg_dialogs_get_info — Get chat/channel metadata

Contacts & Users (6)

• tg_contacts_get — Get contact info
• tg_contacts_search — Search contacts
• tg_users_get — Get user info
• tg_users_get_photos — Get user profile photos
• tg_users_block — Block or unblock a user
• tg_users_get_common_chats — Get chats shared with a user

Groups (9)

• tg_groups_list — List groups
• tg_groups_info — Get group info
• tg_groups_join — Join a public channel or supergroup
• tg_groups_leave — Leave a group or channel
• tg_groups_rename — Rename a group
• tg_groups_members_add — Add a member
• tg_groups_members_remove — Remove a member
• tg_groups_invite_link_get — Get invite link
• tg_groups_invite_link_revoke — Revoke invite link

Chat Management (8)

• tg_chats_create — Create a new group or channel
• tg_chats_archive — Archive or unarchive a chat
• tg_chats_mute — Mute or unmute notifications
• tg_chats_delete — Delete a channel or supergroup
• tg_chats_set_photo — Set chat photo
• tg_chats_set_description — Set chat description
• tg_chats_get_admins — List administrators (channels/supergroups)
• tg_chats_set_permissions — Set default permissions

Media & Files (4)

• tg_messages_send_file — Send a file with caption
• tg_media_download — Download media from a message
• tg_media_upload — Upload a file
• tg_media_send_album — Send a media album

Profile (4)

• tg_profile_get — Get own profile info
• tg_profile_set_name — Update display name
• tg_profile_set_bio — Update bio
• tg_profile_set_photo — Set profile photo

Forum Topics (2)

• tg_topics_list — List forum topics
• tg_topics_search — Search forum topics

Stickers (3)

• tg_stickers_search — Search sticker sets
• tg_stickers_get_set — Get a sticker set
• tg_stickers_send — Send a sticker

Drafts (2)

• tg_drafts_set — Set a draft message
• tg_drafts_clear — Clear a draft

Folders (4)

• tg_folders_list — List chat folders
• tg_folders_create — Create a folder
• tg_folders_edit — Edit a folder
• tg_folders_delete — Delete a folder

Status (2)

• tg_typing_send — Send typing indicator
• tg_online_status_set — Set online/offline status

Server (1)

• tg_server_version — Get build metadata (semver tag, git commit SHA, Go runtime version); reachable before authentication completes

Peer Identifier Format

Every tool that surfaces a peer (sender, forward author, reply target, dialog, group/channel info, contact, user, reaction) uses the same identifier shape in both text output and JSON:

• Text form: Display Name [@username] / [user:N] / [channel:N] / [group:N] / [hidden] / [unknown:N]
• JSON form: every peer-bearing entry carries {id, type, name, username} where type is one of "user" / "channel" / "group" / "unknown"

The "group" label covers only legacy basic groups (MTProto PeerChat). Supergroups and broadcast channels both label as "channel" because gotd represents both as PeerChannel. A consumer can pivot between text and JSON surfaces by pattern-matching on the same literal kind:N form (group:42 appears identically in [group:42] text output and participants[].type="group" + id=42 JSON).

This applies uniformly across:

• tg_messages_* — sender, forwarded-from origin, cross-chat reply target, participants
• tg_dialogs_* — dialog title + username
• tg_users_*, tg_contacts_* — user display name + @handle
• tg_groups_info / tg_groups_list / tg_groups_members_list / tg_chats_admins — group/channel titles, member display names
• tg_messages_get_reactions — reactor display name + @handle
• tg://chat/{peer}/messages resource — same multi-line block format as tg_messages_*

Message Output Format

Breaking changes in this release. Both text and JSON outputs change shape.

• Text — output is no longer a one-line-per-message string with a [ID ↩parent] ts sender: text shape. Each message is now a multi-line block separated by a --- line. The ↩<parent> marker and the [<media>] inline prefix are gone — reply targets land on a dedicated reply to: line and media type on a dedicated media: line. Dialog rows in tg_dialogs_* switch from [type] Title to the unified Title [@username/user:N/...] identifier shape.
• JSON — MessageItem gains fromType, fromUsername, and forward. DialogItem gains username. ParticipantItem gains type and username. ReactionUserItem.userName is removed in favour of separate name and username fields. ContactStatusItem gains the same name/username slots (currently empty pending a follow-up upstream lookup). InputPeer.accessHash becomes omitempty — a zero value (the common case for peers from forwarded-message headers or numeric IDs) now disappears from JSON rather than serializing as "accessHash":0.

Any consumer that parsed the previous formats must be updated.

Read tools (tg_messages_list, tg_messages_get, tg_messages_context, tg_messages_search) return both a JSON messages array and a human-readable output string. Each message in output is a multi-line block; blocks are separated by a literal --- line so a message body containing its own blank lines stays unambiguous.

[<id>] <ISO-timestamp>
from: Display Name [@username]
forwarded from: Display Name [@username] at <ISO-timestamp>
forwarded from channel: Title [@username] #<post> by "<author>" at <ISO-timestamp>
reply to: <parentId>
reply to: <parentId> in Display Name [@username]
quote: «<quoted fragment>»
media: <type>
text:
<message body, multi-line preserved>

Lines are emitted only when their underlying field is populated. A message body that contains a literal --- line on its own (rare — typically a Markdown horizontal rule) collides with the block separator, so parse-back from output is not strictly round-trip safe. The same caveat applies to adversarial content: peer names and usernames are sanitized to stop newline-injection from forging fake from: / reply to: lines, but the body itself is rendered verbatim. A user can craft a body containing \n---\n[999] ts\nfrom: Admin\ntext:\nfake and the rendered output will look like two messages. The JSON messages array is the authoritative shape — body verbatim preservation is a deliberate UX choice for code blocks and quoted text, not a security property. Every peer reference — sender, forwarded-from origin, cross-chat reply target — uses the same identifier shape:

• Display Name [@username] — public username available; the numeric ID is dropped from the text form for brevity (it's still in the JSON messages[].fromId, forward.from.peer.id, etc.)
• Display Name [user:N] / [channel:N] / [group:N] — username not exposed, only ID (labels match participants[].type and fromType exactly)
• Display Name [hidden] — name leaked through but the peer ID is privacy-protected; surfaces on forwarded from: and reply to: ... in lines (typical when the original author enabled forward-privacy). The from: sender line is omitted entirely when both name and ID are absent, since the message host already identifies the chat.
• [user:N] / [hidden] — degenerate forms when display name is also missing
• [unknown:N] — defensive fallback when a PeerType value is outside the three documented kinds; surfaces only if a future MTProto schema bump introduces a fourth peer kind and the response carries it before this client adds a branch

When forward.from is present, name and username may still be empty if the response's Users[]/Chats[] arrays did not include the resolved peer — text output then falls back to the bare [user:N] / [channel:N] form, and JSON exposes {peer: {type, id}} without name/username. Use the peer ID to look the entity up via tg_users_get or tg_dialogs_search when names are needed.

JSON adds forward with structured fields (from.peer, from.name, from.username, fromName for privacy-hidden, date, channelPost, postAuthor), fromUsername and fromType ("user" / "group" / "channel"). The mapping is: "user" for regular senders, "group" for legacy basic groups only, "channel" for both broadcast channels AND supergroups (MTProto represents both as PeerChannel). Original authors of forwarded messages are also included in the participants array, which carries that type string alongside the bare ID so a user and a channel sharing the same numeric ID survive deduplication as distinct entries.

Deep-links to the original message can be constructed from forward.channelPost and forward.from:

• Public channel: https://t.me/<username>/<channelPost>
• Private channel: https://t.me/c/<from.peer.id>/<channelPost>

accessHash is omitted from every serialized InputPeer shape when zero — that includes messages[].peerId, messages[].replyTo.fromPeerId, and messages[].forward.from.peer. The omission is deliberate: a zero hash looks like a valid one to MTProto but raises PEER_ID_INVALID when passed back. For follow-up tool calls against a peer whose accessHash field is missing, resolve it through @username (if exposed) or look it up via tg_dialogs_list to obtain a usable access hash.

tg_messages_search_global is an exception — its output is a one-line summary; per-message structure lives only in the JSON messages array because results span arbitrary peers. It does NOT return a participants field (the per-peer accessHash resolution would be unreliable across arbitrary chats). Callers that need to act on a sender or forward-author surfaced by global search must first resolve the peer via @username (if present in messages[].fromUsername) or tg_dialogs_list before passing it back into MTProto — accessHash on the embedded InputPeer will be omitted whenever it is unknown.

Markdown — Known Limitations

The CommonMark subset supported via parseMode: "commonmark" covers most everyday formatting, but a handful of CommonMark spec features are intentionally not implemented. Each is captured as a commented-out test in internal/telegram/markdown_audit_test.go ready to be unblocked when work begins.

• Nested blockquotes (> > x). The inner > is treated as literal content of the outer blockquote rather than producing a nested level. Telegram renders any depth of > as a single quote bar visually, so the practical loss is minor.
• Nested emphasis (**bold *italic***). The inner italic is dropped and its asterisks are kept as literal characters. Implementing the full delimiter-run algorithm from CommonMark §6.4 would be a rewrite of the inline parser.
• Hard line breaks via two trailing spaces or \ (CommonMark §6.7). Telegram has no break entity; a plain \n already renders as a line break. Stripping the trailing whitespace would be silent data corruption when the user did not intend a hard break, so the parser passes both forms through unchanged.

Resources

• tg://dialogs — List of all dialogs (JSON)
• tg://profile — Authenticated user's profile (JSON)
• tg://chat/{peer} — Chat/channel metadata (JSON, URI template)
• tg://chat/{peer}/messages — Recent messages (text, URI template)

Prompts

• reply_to_message — Fetch context around a message for composing replies
• summarize_chat — Fetch recent messages for conversation summarization
• search_and_reply — Search messages and prepare reply context

Peer Resolution

All tools accept peer as a string. Supported formats:

• @username
• username (bare)
• https://t.me/username
• https://t.me/+invite_hash (invite links, if already joined)
• Numeric ID (bot-API style: positive=user, negative=chat, -100xxx=channel)

Peers resolved by username include a valid access hash. Numeric IDs use a cached access hash if available, otherwise AccessHash=0 (some API calls may fail — prefer @username).

Configuration

Variable	Description	Default	Required
TELEGRAM_APP_ID	API app_id from my.telegram.org	—	Yes
TELEGRAM_APP_HASH	API app_hash from my.telegram.org	—	Yes
TELEGRAM_PHONE	Phone number (E.164 format)	—	No (prompted via elicitation)
TELEGRAM_PASSWORD	2FA password	—	No (prompted via elicitation)
TELEGRAM_SESSION_FILE	Session file path	~/.mcp-tg/session.json	No
TELEGRAM_AUTH_CODE	One-time auth code	—	No (prompted via elicitation)
TELEGRAM_DOWNLOAD_DIR	Media download directory	/tmp/mcp-tg/downloads	No
MCP_HTTP_PORT	HTTP/SSE transport port	disabled	No
MCP_HTTP_HOST	HTTP bind address	127.0.0.1	No

Authentication

Authentication uses a cascade: environment variable, then MCP elicitation (the client prompts you), then error.

First run:

1. Set TELEGRAM_APP_ID and TELEGRAM_APP_HASH (always required)
2. Optionally set TELEGRAM_PHONE — if not set, the server asks via elicitation
3. Telegram sends a code to your device
4. Optionally set TELEGRAM_AUTH_CODE — if not set, the server asks via elicitation
5. If 2FA is enabled, optionally set TELEGRAM_PASSWORD — or the server asks
6. Session is saved to TELEGRAM_SESSION_FILE

Subsequent runs: session file is loaded automatically, no auth needed.

Session persistence in containers: mount a volume for the session file:

-v ~/.mcp-tg:/home/nobody/.mcp-tg

Multiple sessions: each Claude Code session starts its own container. This is safe for normal use — Telegram allows multiple MTProto connections with the same auth key. However, avoid running many instances simultaneously (5+), as Telegram may rate-limit or drop connections. Session file writes are rare (only on re-auth or DC migration) so volume sharing is safe in practice.

Usage

With Claude Code (stdio via Docker)

claude mcp add mcp-tg -- docker run --rm -i \
  -e TELEGRAM_APP_ID \
  -e TELEGRAM_APP_HASH \
  -v ~/.mcp-tg:/home/nobody/.mcp-tg \
  ghcr.io/lexfrei/mcp-tg:latest

Direct binary

export TELEGRAM_APP_ID=12345
export TELEGRAM_APP_HASH=your_app_hash
./mcp-tg

Container

docker run --rm -i \
  -e TELEGRAM_APP_ID=12345 \
  -e TELEGRAM_APP_HASH=your_app_hash \
  -v ~/.mcp-tg:/home/nobody/.mcp-tg \
  ghcr.io/lexfrei/mcp-tg:latest

Requirements

• Go 1.26.1+
• Telegram API credentials from my.telegram.org

Building

go build ./cmd/mcp-tg

docker build --file Containerfile --tag mcp-tg .

License

BSD 3-Clause License