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 of behavioral disclosure but fails to mention critical DAW-specific behaviors: whether this affects existing audio items (time-stretching), valid BPM ranges, or if the change is immediate/undoable.

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?

Extremely terse at six words with no filler. The single sentence earns its place by conveying the core operation. However, 'appropriately sized' is borderline given the lack of schema documentation and behavioral complexity implied by the DAW context.

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?

Minimum viable for a single-parameter setter. Adequately identifies the function but leaves significant gaps regarding side effects, valid input ranges, and interaction with project state (e.g., during playback vs stopped).

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?

Schema coverage is 0% (parameter title is just 'Bpm'). The description compensates minimally by indicating the unit is 'BPM' (beats per minute), but does not describe valid ranges, expected precision (integers vs floats), or whether values are clamped.

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?

The description clearly states the action ('Set'), the target ('project tempo'), and the unit ('BPM'), distinguishing it from siblings like set_time_signature or set_track_volume. However, it lacks explicit scope clarification (e.g., whether this affects the entire project globally).

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?

No guidance provided on when to use this versus alternatives, prerequisites (e.g., project must be loaded), or side effects. The description states what it does but not when or why to use it.

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