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nickbeentjes

mac-audio-router-mcp

by nickbeentjes

get_volume

Retrieve the current macOS system output volume level as a number from 0 to 100. Use it to check volume before adjusting audio routing or playback.

Instructions

Get the current system output volume level (0-100)

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

A3.5/5.0
Behavior3/5

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

No annotations exist, so the description carries the full burden. It discloses the return range (0-100), which is genuinely useful behavioral context for a getter, and 'Get the current' strongly implies a non-mutating read. However, it says nothing about permissions, side effects, or which device/zone the volume pertains to.

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?

A single front-loaded sentence naming the resource and the value range, with no filler. Nothing to trim.

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

Completeness4/5

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

For a zero-parameter read tool with no output schema, the description supplies the one thing an agent needs — the 0-100 scale of the returned level. It does not clarify the scope of 'system' (global vs. device vs. zone) despite siblings for zones and devices, which is a minor gap.

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?

The tool takes zero parameters, so there is nothing to document; baseline 4 applies. The description correctly focuses on the return value scale instead of inventing parameter detail.

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?

States a specific verb and resource (get current system output volume level) and adds the value scale (0-100), which distinguishes it from the mutation siblings like set_volume. It does not explicitly contrast itself with get_audio_status or set_device_volume, which would have made the routing unambiguous.

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 statement of when to call this versus set_volume, get_audio_status, or set_device_volume. Usage is only implied by the verb 'get'. With 15 sibling tools in the same audio domain, some routing guidance was warranted.

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