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

With no annotations provided, the description carries full burden. It details transformation logic for each mode and mentions return values ('Returns count of notes modified, original and new duration stats'). However, it does not disclose if the operation is destructive or reversible, nor any prerequisites like region existence.

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 well-structured with headings and examples, front-loading the purpose. While it is relatively long, every sentence adds necessary detail for a complex tool. Minor redundancy could be trimmed, but overall efficient.

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 8 parameters, 0% schema coverage, and no annotations, the description is remarkably comprehensive. It covers all parameter semantics, modes, and includes examples. The output schema exists and description mentions the return value, so no gaps remain.

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 has 0% parameter description coverage, so the description must compensate. It thoroughly explains all 8 parameters, including modes with 5 options, value semantics per mode, region_index, min/max_duration, quantize grid, and provides clear examples. This fully compensates for the lack of schema descriptions.

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's purpose: 'Scale the duration of all notes in a region — MIDI note length control.' It explicitly distinguishes from sibling tool scale_velocity by stating 'Like scale_velocity but for note durations,' making the action specific and differentiating it from nearby similar tools.

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 provides context on when to use the tool: 'Useful for changing articulation globally — make all notes shorter (staccato feel), longer (legato feel), or snap to a grid.' It doesn't explicitly state when not to use it, but the comparative mention with scale_velocity implies alternatives for velocity scaling.

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