Skip to main content
Glama

reaper_list_installed_fx

Read-onlyIdempotent

Lists all FX plugins scanned by Reaper (VST2/VST3/CLAP/JS) with names to use when adding effects to tracks. Supports filtering and pagination.

Instructions

List every FX plugin Reaper has scanned (VST2/VST3/CLAP/JS).

Reads Reaper's own scan-cache files directly (no bridge round-trip). Use this to find the exact fx_name string to pass to reaper_add_fx_to_track.

Each item: name (pass this to add_fx, e.g. "VST3i: Serum (Xfer Records)"), kind (VST/VSTi/VST3/VST3i/CLAP/CLAPi/JS), is_instrument (bool), filename.

Result is paginated. The response wraps the page in {total, count, offset, has_more, next_offset, items}.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
name_filterNoCase-insensitive substring to narrow results (e.g. 'serum', 'reacomp')
instruments_onlyNoIf true, return only synths/samplers (instruments)
limitNoMaximum results to return
offsetNoNumber of results to skip for pagination
response_formatNo'markdown' for human-readable output or 'json' for machine-readablemarkdown

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
resultYes
Behavior4/5

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

Annotations already declare readOnly, not destructive, idempotent. The description adds that it reads scan-cache files directly (no bridge round-trip), which is helpful behavioral context. No contradictions.

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 six sentences, each adding value: purpose, implementation, usage hint, item structure, pagination, response format. It is front-loaded and efficient.

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?

The description covers purpose, implementation, usage, item structure, and pagination. It does not mention performance or limits beyond the max 2000, but it is fairly complete for a listing tool with good annotations and schema.

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 100% and each parameter has a good description in the schema. The description does not add new parameter-level semantics beyond what the schema provides, so baseline 3 is appropriate.

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 tool lists every FX plugin, specifies categories (VST2/VST3/CLAP/JS), and explains it reads scan-cache files. It distinguishes from siblings by providing the exact fx_name for reaper_add_fx_to_track.

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?

The description explicitly says to use this tool to find the exact fx_name for reaper_add_fx_to_track. It does not explicitly exclude alternatives like reaper_list_track_fx, but the sibling tools list provides context.

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

Install Server

Other Tools

Latest Blog Posts

MCP directory API

We provide all the information about MCP servers via our MCP API.

curl -X GET 'https://glama.ai/api/mcp/v1/servers/T-Rzeznik/reaper-mcp'

If you have feedback or need assistance with the MCP directory API, please join our Discord server