modularsynth-mcp

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Add module

add_module

Place a module in the rack at an optional row and x position, set its parameters, and return its ID; use it to build voices, drums, samplers, or mic input.

Instructions

Add a module to the rack. Optional row and x (in HP) place it; otherwise it goes to the first free spot. Optional params set its knobs. Returns its id. Drums: synthesize them with modules (VCO, Noise, VCF, ADSR, VCA) or load the built-in kit into samplers with set_sample. For a real instrument or a voice, a sampler with the user’s recording, or audioin for a microphone.

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": {
      "type": "<type>"
    },
    "name": "add_module"
  }
}

Input Schema

Name	Required	Description	Default
`x`	No
`row`	No
`type`	Yes
`params`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.3.1Nov 2, 2026

TDQS

A3.6/5.0

Behavior3/5

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

Annotations already declare a safe, non-destructive write in a closed world, so the bar is lower. The description usefully adds default placement behavior ("first free spot") and the return value ("Returns its id") since there is no output schema, but says nothing about failures on invalid type or how params interact with an existing module's state.

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?

Front-loaded with purpose and placement semantics, then params and return value, then sound-design guidance. The closing drum/instrument sentences are on the long side but carry real decision value rather than filler.

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?

For a 4-parameter mutation tool with no output schema and no schema descriptions, the definition covers placement, knob values, and return identity adequately. It stops short of the one thing an agent most needs — how to obtain a valid `type` string — leaving a meaningful gap.

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 coverage is 0%, so the description carries the burden and partially meets it: it explains x is in HP, that row/x are optional placement with a first-free-spot fallback, and that params set knobs. It never enumerates or points to valid `type` values (the required parameter) and omits the 0-400 / 0-20 ranges.

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?

Opens with a specific verb+resource ("Add a module to the rack") and contrasts the approach against set_sample for drums, so it is separable from remove_module and the sample-loading sibling. The differentiation is use-case driven rather than a crisp tool boundary, which keeps it from a 5.

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

Usage Guidelines4/5

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

Gives concrete routing guidance: drums can be built from VCO/Noise/VCF/ADSR/VCA modules or via set_sample, real instruments via sampler, microphones via audioin. It lacks explicit "when not to use" guidance and never points at list_module_types for discovering valid types, which is the biggest omission.

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