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

Annotations already declare readOnlyHint=true and destructiveHint=false, but the description adds substantial behavioral context: it's cached after the first call, times are in SOURCE seconds, and it mentions that a confidence below 0.5 makes the pulse unreliable and causes beat_align_cuts to refuse. This goes well beyond the annotations and helps the agent anticipate side effects.

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?

Every sentence earns its place. The description is front-loaded with 'PROJECT-SCOPED' and 'READ', then delivers precise details without fluff. It's dense but not verbose, and the structure flows logically from purpose to outputs to usage.

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?

Despite no output schema, the description enumerates all key return values (tempo with confidence, beat count, timestamps, energy sections, stressed words) and ties them to usage. It also addresses the optional asset_key scenario. For a tool with this complexity, nothing essential is missing.

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?

With only 50% schema coverage, the description compensates thoroughly. It explains project_id as an immutable scope and instructs to copy it from specific tools, explicitly stating the active-project pointer is never used. For asset_key, it clarifies it's an uploaded or fetched music file and gives a concrete use case. This adds significant 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 clearly states the tool's purpose: a read-only call that returns musical/energy analysis of the source audio, with specific outputs (tempo, beats, energy sections, stressed words). It differentiates itself by noting it is project-scoped and references sibling tools (beat_align_cuts, punch_in_on_emphasis) and explains how it relates to them. It also mentions the alternative use via asset_key.

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?

Explicitly states when to use: 'Call before beat_align_cuts / punch_in_on_emphasis, or to answer "what's the tempo".' It also explains the asset_key alternative for analyzing a different asset, with an example. This gives clear context for when this tool is appropriate versus alternatives.

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