reaper-reapy-mcp

by wegitor

Overview Schema Source Related Servers Discussions Admin

Python

Local

toggle_fx

Enable or disable an FX on a REAPER track by specifying the track and FX index, with an optional state to set.

Instructions

Toggle or set the enable/disable state of an FX.

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": {
      "track_index": "<track_index>",
      "fx_index": "<fx_index>"
    },
    "name": "toggle_fx"
  }
}

Input Schema

Name	Required	Description	Default
`enable`	No
`fx_index`	Yes
`track_index`	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 only states that the tool toggles or sets an FX's enable state, but it does not explain the difference when the 'enable' parameter is null versus a boolean, how invalid indices are handled, or what the output/return value looks like. This is insufficient 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, front-loaded sentence of 12 words that directly states the tool's purpose. Every word is informative, with no redundant or vague filler, earning a perfect score for conciseness.

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 zero annotations, 0% schema description coverage, and the presence of an output schema, the description is too sparse to fully support correct invocation. It lacks essential details such as toggle/set semantics, index conventions, and behavior in edge cases, leaving the agent to guess at critical aspects.

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?

Schema description coverage is 0%, so the description must compensate. It clarifies that the tool can toggle or set the enable state, giving some meaning to the 'enable' parameter, but it leaves 'track_index' and 'fx_index' undefined—no indication of indexing base, bounds, or expected format. The partial clarification is not enough.

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 clearly states the action ('Toggle or set') and the resource ('enable/disable state of an FX'), which is specific enough to distinguish this from sibling tools like add_fx, remove_fx, and set_fx_param. It precisely communicates the tool's core function.

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?

The description implies usage for enabling, disabling, or toggling FX state, but it provides no explicit guidance on when to prefer this tool over alternatives, nor does it mention any exclusions or prerequisites. The context from sibling names is not leveraged in the description.

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