reaper-reapy-mcp

Overview Schema Source Related Servers Discussions Admin

set_master_volume

Set the master track volume in REAPER to control the overall output level. Provide a numeric value to adjust the project's loudness.

Instructions

Set the master track volume.

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": "<volume>"
    },
    "name": "set_master_volume"
  }
}

Input Schema

Name	Required	Description	Default
`volume`	Yes

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.4Aug 7, 2026

TDQS

B3.3/5.0

Behavior2/5

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

No annotations are provided, so the description must carry the full burden of behavioral disclosure. It states that the tool sets the volume but does not explain the effect on current volume, units, or range. This is a significant 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, direct sentence with no filler. It is appropriately concise for the tool's simplicity and front-loads the key action and target.

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 low schema coverage and missing annotations, the description is too sparse. It omits critical details like volume scale (e.g., 0.0–1.0, dB) and does not clarify whether the value is absolute or relative. The output schema exists, but that does not compensate for the lack of parameter context.

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

Parameters2/5

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

The schema has zero description coverage for the 'volume' parameter, and the description does not compensate. It simply repeats the word 'volume' without explaining its meaning, units, or accepted range. The description fails to add value beyond 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?

The description 'Set the master track volume' clearly identifies the action (set) and the resource (master track volume). It is unambiguous and distinguishes itself from sibling tools like 'set_master_pan' and 'toggle_master_mute'.

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?

Usage context is implied by the tool's name and description, but there is no explicit guidance about when to use it or alternatives. It does not mention any exclusions or prerequisites, such as acceptable volume values or whether the track must exist.

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