REAPER MCP Server

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

With no annotations provided, the description carries the full burden. It successfully documents the internal composition of each preset signal chain (EQ > Comp > Limiter, etc.), but does not clarify whether the operation appends to existing master FX or replaces them, nor does it mention any potential destructive side effects on existing project settings.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Four sentences with zero waste. Purpose is front-loaded in sentence one, parameter options detailed in sentence two, and workflow integration in sentences three-four. Every sentence provides distinct value not available in the structured schema or annotations.

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

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

For a single-parameter tool without output schema, the description is complete. It documents the parameter domain, provides the post-invocation workflow, and references related discovery tools. No gaps remain that would prevent correct agent invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema has 0% description coverage for the 'preset' parameter. The description compensates exceptionally by enumerating the three valid string values (default, loud, gentle) and explaining the specific signal chain and processing intensity each represents ('Comp x2' vs 'light Comp'), effectively serving as the parameter documentation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Clearly states the specific action (Add), resource (standard mastering FX chain), and target (master track). The preset examples (default/loud/gentle) effectively distinguish this from sibling tools like 'add_master_fx' which likely adds individual effects rather than complete chains.

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

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

Provides explicit workflow guidance by naming specific sibling tools to use afterwards ('After applying, use set_master_fx_parameter') and for discovery ('Use list_master_fx + get_fx_parameters'). This creates a clear operational sequence that helps the agent understand when and how to invoke this tool within a larger workflow.

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