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 discloses the return value (item_id) and initial state ('empty'), which is crucial behavioral context. However, it omits mutation details, error conditions, and whether the operation is undoable or has side effects on project state.

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?

Two sentences with zero waste: first establishes the core action, second clarifies the return value and workflow integration. Information is front-loaded and every word earns its place.

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?

Adequate for basic invocation given the mention of item_id return, but incomplete due to missing parameter documentation. Given zero schema coverage and no output schema, the description should have specified parameter semantics (units, indexing) to be fully complete.

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 description coverage is 0%, requiring the description to compensate for all three parameters. It fails entirely—no mention of units (seconds vs. beats), indexing scheme (0-based vs 1-based), valid ranges, or semantics for track_index, start_position, or length. The agent has no context to populate these correctly.

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?

Description clearly states the specific action (Create), resource (empty MIDI item), and location (on a track). The mention of 'empty' distinguishes it from import operations, and naming 'add_midi_note' clarifies its role in the workflow relative to siblings.

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?

The description establishes the critical workflow relationship with sibling tool 'add_midi_note' by stating the return value is for use with that tool. However, it lacks explicit 'when not to use' guidance (e.g., vs. importing existing MIDI files) or prerequisites (track must exist).

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