vlc-mcp

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set_volume

Adjust VLC's playback volume to any level from 0 to 200, where 100 is normal, so you can raise or lower audio precisely during playback.

Instructions

Set the volume level of VLC (0-200, where 100 is normal volume).

Args: volume_level: An integer between 0 and 200 representing the volume percentage

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": {
      "volume_level": "<volume_level>"
    },
    "name": "set_volume"
  }
}

Input Schema

Name	Required	Description	Default
`volume_level`	Yes

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 12, 2026

TDQS

B3.1/5.0

Behavior2/5

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

No annotations are supplied, so the description carries the full behavioral burden, and it discloses almost nothing beyond the value scale. It doesn't say whether out-of-range input errors or is clamped, whether VLC must be running, whether the change persists, or whether it affects current playback only.

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?

The opening line is front-loaded and complete, and the Args block is short. The Args block does repeat the range already stated in the first sentence, which is mild redundancy but not harmful.

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?

With one required parameter and an output schema present, the description covers the essential input semantics. It is still thin for a mutation tool with zero annotations: boundary behavior and the relationship to the near-identical 'adjust_volume' sibling are unaddressed.

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 description coverage is 0% and the schema only says 'integer' with no title detail, so the description is the sole source of meaning. It supplies the range (0-200), the unit (percentage) and the reference point (100 = normal), which is exactly the missing semantics for this parameter.

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

Purpose4/5

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

The description names a specific verb ('Set') and resource ('the volume level of VLC') and immediately defines the scale, so the agent knows exactly what the tool does. It does not, however, distinguish itself from the sibling 'adjust_volume', which an agent could easily confuse with a setter.

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?

There is no when-to-use or when-not-to-use guidance at all. Given a sibling named 'adjust_volume' that plausibly does relative changes while this does absolute setting, the description should have stated that routing rule; the agent must infer it from the name alone.

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