telegram-mcp

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join_chat

Join Telegram groups or channels by submitting a @username, public t.me link, or invitation link, granting access to the chat.

Instructions

Вступить в группу/канал по @username, публичной ссылке t.me/name или ссылке-приглашению t.me/+hash (t.me/joinchat/hash).

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "link": "<link>"
    },
    "name": "join_chat"
  }
}

Input Schema

Name	Required	Description	Default
`link`	Yes

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 28, 2026

TDQS

A3.8/5.0

Behavior2/5

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

There are no annotations, so the description must carry the full burden. It only states the join action and link formats, with no mention of side effects, authentication requirements, failure modes for invalid links, or behavior when already a member. This is a meaningful transparency gap for a mutating operation.

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 a single compact sentence that front-loads the core purpose and immediately provides the essential parameter guidance. There is no redundant or filler content.

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

Completeness3/5

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

The tool is simple with one parameter and an output schema, so the description covers the basic invocation. However, it omits behavioral and environmental context such as the need for an authenticated session and error handling for invalid or expired invitation links. These are not covered by annotations, leaving some gaps.

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

Parameters5/5

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

The input schema provides only a bare 'link' string with 0% schema description coverage. The description compensates thoroughly by specifying all accepted formats: @username, t.me/name, t.me/+hash, and t.me/joinchat/hash. This gives the agent precise guidance for constructing the parameter value.

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?

The description clearly states the action (joining) and the resource (group/channel), and enumerates the accepted link formats (@username, public t.me/name links, and invite links). This makes it immediately distinguishable from sibling tools like leave_chat or resolve_chat.

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

Usage Guidelines3/5

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

The description implies when to use the tool: when the user wants to join a chat using a supported link. However, it does not explicitly mention alternatives or conditions where this tool should not be used, such as distinguishing it from resolve_chat for mere lookup.

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