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

With no annotations provided, the description carries full burden. It discloses behavioral traits: applies independent transformations to drums, bass, melody, and harmony; explains the effect of parameters like drum_density, bass_octave_shift, and melody_transform; and states that it returns 'notes per track and transformations applied.' This provides good transparency for a creation tool.

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 fairly long but well-structured. It starts with a clear purpose statement, then breaks down transformations per track, lists parameters with explanations, and provides two usage examples. Every sentence adds value, and the examples help illustrate usage. Could be slightly more concise, but it earns its length.

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 tool's complexity (19 parameters, 1 required) and the existence of an output schema, the description adequately covers the main parameters, explains transformations, and provides examples. It mentions return values. It doesn't cover all edge cases, but for a creative music tool, it is complete enough to guide an AI agent.

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%, but the description compensates exceptionally. It explains each parameter with concrete examples: drum_density ('0.3 = sparse, 1.0 = normal, 1.5 = busy'), bass_octave_shift ('0 = normal, +1 = octave up'), melody_transform lists allowed values, and include_* booleans. This adds substantial meaning beyond the schema.

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 immediately states the tool creates 'a musically varied section — not a repeat, a real variation.' It explicitly contrasts with sibling tool create_genre_sections (which repeats loops at different velocities), clearly distinguishing the tool's unique capability. The verb 'create' and resource 'arrangement variation' are specific.

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 explains when to use this tool: 'to build a song where each section has real musical variation, not just energy changes.' It differentiates from create_genre_sections and provides concrete examples (breakdown, bridge). It does not explicitly state when not to use it, but the contrast with the sibling and the detailed parameter guidance imply appropriate contexts.

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