viber-mcp

send_file

Send a file to a Viber user by providing the receiver's ID, a public file URL, file size, and file name.

Instructions

Send a file attachment to a Viber user

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": {
      "receiver": "<receiver>",
      "media": "<media>",
      "size": "<size>",
      "file_name": "<file_name>"
    },
    "name": "send_file"
  }
}

Input Schema

Name	Required	Description
`receiver`	Yes	Viber user ID of the receiver
`media`	Yes	Public URL of the file (≤50MB; see Viber docs for forbidden extensions)
`size`	Yes	File size in bytes
`file_name`	Yes	File name with extension
`sender_name`	No	Display name override (≤28 chars)
`sender_avatar`	No	Avatar URL override

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0May 26, 2026

TDQS

C2.9/5.0

Behavior1/5

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

No annotations provided, and the description does not disclose any behavioral traits beyond the basic action. It fails to mention important aspects like file size limits, required public URL, or that the user must be online to receive the file. The entire burden is on the schema.

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

Conciseness4/5

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

A single, front-loaded sentence conveys the core purpose efficiently. However, it could be slightly more structured to include key constraints.

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

Completeness2/5

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

Given the parameter count (6) and absence of output schema and annotations, the description is too minimal. It does not cover return values, error scenarios, or prerequisites (e.g., ensuring the file URL is accessible).

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

Parameters3/5

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

Schema description coverage is 100%, with each parameter having a clear description. The tool description adds no additional meaning beyond what the schema provides, so a baseline of 3 is appropriate.

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 'Send a file attachment to a Viber user' clearly states the action (send) and resource (file attachment), distinguishing it from sibling tools like send_picture or send_video by specifying 'file'.

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

Usage Guidelines2/5

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

No guidance on when to use this tool versus alternatives like send_picture or send_video. Missing context on prerequisites or conditions (e.g., user must be a Viber user with an active chat).

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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