reaper-reapy-mcp

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get_fx_param

Retrieve the current value of a specific effect parameter on a REAPER track by supplying track, FX, and parameter names. Enables automated monitoring and control of effect settings.

Instructions

Get an FX parameter value.

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>",
      "param_name": "<param_name>"
    },
    "name": "get_fx_param"
  }
}

Input Schema

Name	Required	Description	Default
`fx_index`	Yes
`param_name`	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

C2.7/5.0

Behavior2/5

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

With no annotations, the description carries the full burden of behavioral disclosure. It only says 'Get an FX parameter value' and omits important details such as parameter index base, matching behavior for param_name, error handling, or whether the value is returned as a number or string. These gaps are not addressed.

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 description is a single, front-loaded sentence with no redundancy, making it highly concise. However, it is so terse that it borders on under-specification, missing useful details that could be included without bloat.

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?

For a three-parameter getter with an output schema, the description is incomplete. It lacks usage context, parameter semantics, and behavioral notes. The output schema may cover return format, but the description does not address other essential aspects of using the tool correctly.

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%, and the description adds no meaning to the parameters. It does not explain track_index, fx_index, or param_name, nor how they determine the returned value. The parameter names are somewhat self-explanatory, but the description fails to compensate for the lack of schema documentation.

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 clearly states the action ('Get') and the resource ('FX parameter value'), identifying it as a getter for a single FX parameter. It is distinguishable from sibling tools like set_fx_param (write) and get_fx_param_list (list all params), though it does not explicitly state 'single' vs. multiple values.

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?

No guidance is provided on when to use this tool versus alternatives. There is no mention of related tools like set_fx_param or get_fx_param_list, nor any context about prerequisites or typical use cases.

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