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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds what the annotations cannot: the actual computed outputs, including a qualitative 'how noticeable it will sound' judgement and pitch drift under non-time-stretched playback. That is genuinely useful behavioral context for a pure-calculation 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?

One dense sentence with no filler, and the primary output (percent change and playback rate) is front-loaded ahead of the secondary derived figures. It is a sentence fragment, but nothing is wasted.

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?

There is no output schema and no annotations gap to cover, so the description must enumerate return values itself, which it does across four distinct result categories. For a 2-parameter deterministic calculator, an agent has everything needed to call it and interpret the response.

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 100% and both parameters carry their own descriptions with min/max bounds, so 'from one BPM to another' merely restates from_bpm/to_bpm. Baseline 3 applies; the description adds no unit, format, or edge-case semantics 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 names a specific resource: percent change and playback rate between two BPMs, plus derived figures (noticeability, pitch drift, half/double time). It is a noun-phrase list rather than a verb statement, but an agent can still tell this is a tempo-math calculator and distinguish it from siblings like transpose or camelot.

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?

Usage is only implied: the mention of 'pitch change if it is not time-stretched' hints that speed_pitch handles the time-stretch case, but the description never says when to choose this tool over speed_pitch or check_mix, nor does it state any exclusions or prerequisites.

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