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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It richly explains feedback modes with concrete examples (e.g., 'linear — each repeat is velocity_decay × previous (0.6 → 0.6, 0.36, 0.216)'), pitch shift semantics, and dest_track behavior. It notes that 'Each repeat copies ALL notes from the source' and mentions the return summary. However, it does not explicitly state whether the original notes are preserved or modified, or how region boundaries are handled, leaving minor gaps.

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 sections for feedback_mode, pitch_shift, dest_track, repeats/delay_beats, a parameter summary, and examples. It is slightly redundant because the parameter list repeats prior explanations, and the length is substantial (~350 words). However, every section adds useful detail, and the examples are illuminating. Slight trimming could make it more concise, but it is not bloated.

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 (9 parameters) and the 0% schema description coverage, the description covers all needed context: all parameters are explained, return value is mentioned ('Returns echo summary with per-repeat velocity and pitch info'), and two usage examples are provided. It lacks explicit prerequisites or error conditions (e.g., needing a note region, valid unit index), but these are largely implied by the parameter naming and the phrase 'Takes existing notes from a region.'

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?

The input schema has no descriptions (0% coverage), but the description fully compensates by explaining every parameter. It provides detailed semantics for feedback_mode (with behavior of each value), pitch_shift (with musical examples like '+12 = octave up'), dest_track (same vs separate track), and delay_beats (with note-value equivalents). The narrative section and the parameter summary together give comprehensive meaning beyond the bare schema titles.

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: 'Create MIDI echo — repeat notes with decaying velocity and optional pitch shift.' It specifies the resource (existing notes in a region), the action (creates echoing repeats), and the effect (delay, decay, pitch shift). This distinguishes it from sibling tools like repeat_notes or create_stutter by emphasizing the echo/delay character.

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 creative context by saying 'This is a creative effect, not a simple copy — think guitar delay throws, synth echo fills, vocal repeat stutters.' This implies when to use it (for echo-like effects) and contrasts it with a simple copy, giving some differentiation from repeat tools. However, it does not explicitly name alternative tools or state when NOT to use it, so it falls short of a 5.

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