fast-mcp-telegram

by io.github.leshchenko1979

Invoke MTProto

invoke_mtproto

Destructive

Low-level Telegram API (MTProto) invoke for methods not wrapped by other tools. Dangerous methods require allow_dangerous=true. Success: API result dict or normalized error. PII and credential-shaped fields (phone, access_hash) are dropped from a successful result by default; pass include_sensitive=true for the raw payload. A bare message id needs a chat binding: requests with no peer field (messages.GetMessages, messages.DeleteMessages) are refused, because a bare id resolves against an arbitrary dialog. Use channels.GetMessages or messages.GetHistory, which carry the binding. messages.GetHistory cannot address a forum topic (no thread_id/top_msg_id in the schema, and channels.GetHistory does not exist) -- use messages.Search with top_msg_id, or the high-level get_messages with reply_to_id. Full documentation: https://github.com/leshchenko1979/fast-mcp-telegram/blob/main/docs/Tools-Reference.md

Input Schema

TableJSON Schema

Name	Required	Description
`resolve`	No	If true, resolve string/int peer-like fields to TL Input* entities before invoke.
`params_json`	Yes	JSON object string of TL parameters as in Telegram API docs; nested TL uses "_": "typeName" discriminator.
`allow_dangerous`	No	If false, destructive methods (e.g. deletes) are blocked. Set true only when intended.
`method_full_name`	Yes	Telegram API method, e.g. "messages.GetHistory" or "users.GetFullUser" (normalization applied).
`include_sensitive`	No	If true, return the raw result including PII and credential-shaped fields (phone, access_hash). Default false drops them.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`_`	No
`id`	No
`ok`	No
`code`	No
`date`	No
`chats`	No
`error`	No
`users`	No
`action`	No
`params`	No
`result`	No
`messages`	No
`exception`	No
`operation`	No
`error_code`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedSep 25, 2026

addedInput schema / properties / include_sensitive

Added value: +{
+  "default": false,
+  "description": "If true, return the raw result including PII and credential-shaped fields (phone, access_hash). Default false drops them.",
+  "type": "boolean"
+}

removedOutput schema / properties / result / additionalProperties
```
Removed value: -true
```
removedOutput schema / properties / result / type
```
Removed value: -"object"
```

First observedJun 18, 2026

TDQS

A4.9/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond annotations that only indicate openWorldHint and destructiveHint, the description discloses concrete behavior: dangerous methods are blocked unless allow_dangerous=true, PII/credential-shaped fields are stripped by default, include_sensitive=true returns the raw payload, bare message id requests without a peer field are refused, and messages.GetHistory cannot address forum topics. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with purpose, then safety, result semantics, and edge-case constraints. Each sentence contributes distinct information, and the documentation link provides an exit for deeper details without bloating the text.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a broad low-level invoke tool, the description covers safety gating, sensitive-data filtering, peer-binding requirements, a difficult forum-topic edge case, and points to full documentation. Since an output schema exists, the response shape does not need to be re-explained.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3. Description adds operational meaning for params_json through the chat-binding rule and forum-topic caveat, and reinforces include_sensitive behavior by naming phone and access_hash. This is modest but genuine added value over the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description says 'Low-level Telegram API (MTProto) invoke for methods not wrapped by other tools,' naming the verb, resource, and scope. It also differentiates itself from the higher-level sibling tools by explicitly framing itself as the fallback for unwrapped methods.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

States clearly to use it for methods not wrapped by other tools. It gives explicit routing guidance: use channels.GetMessages or messages.GetHistory with the chat binding, and messages.Search or get_messages for forum topics. It also explains when allow_dangerous=true is required.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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