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 disclosure burden. It successfully notes the voicing around middle C (MIDI 60) and that output is a single MIDI item, but omits critical behavioral details like whether this overwrites existing items, error handling for invalid track indices, or tempo/time signature interactions.

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?

The description is efficiently structured with four information-dense sentences: purpose statement, parameter format with examples, supported chord types, and voicing details. No redundancy or filler text exists; every sentence adds necessary information not present in structured fields.

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?

Given the lack of annotations, output schema, and schema parameter descriptions, the description provides adequate but incomplete coverage. It comprehensively handles the complex chords parameter but leaves gaps in explaining other parameters and the return value or side effects of the creation operation.

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%, requiring the description to compensate. It excellently documents the chords parameter syntax with examples and supported qualities, but fails to specify units for start_position (beats vs seconds) or clarify beats_per_chord behavior beyond the schema default value.

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 tool creates a chord progression as a single MIDI item on a track, using specific verbs and resources. It effectively distinguishes itself from sibling tools like create_midi_item (generic) and create_drum_pattern by specifying chord-focused functionality.

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?

While the chord syntax explanation implies this is for harmonic progression creation, there is no explicit guidance on when to use this versus create_midi_item for individual notes, or prerequisites like track existence. The description lacks 'when-not-to-use' guidance or alternative recommendations.

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