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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint, so 'Free; changes nothing' is confirmatory. What the description genuinely adds is the return shape ('one picture of numbered frames with the notes struck just before each') and the explicit prohibition on fetching the video itself, both real behavioral context beyond structured fields.

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?

Three tight sentences with no filler; the core capability and the return value are front-loaded, and the operational warning closes it out. Slightly idiosyncratic phrasing ('Look at the player') but every sentence carries information.

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?

With 7 params, no output schema, and annotations covering the safety profile, the description supplies the missing piece — what the image returned actually contains and how frames relate to note attacks. Adding a word on revision or crop defaults would make it complete, but nothing an agent needs is absent.

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 86%, so most parameters (crop, frames, columns, seconds, measures, revision) are already well documented in the schema. The description adds essentially nothing param-specific beyond the notion of numbered frames with attacks, so baseline 3 applies.

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?

States a specific verb+resource: inspecting the player in a video-based score's own video to answer concrete questions (which hand, hand position, strumming, who plays a line). The 'score's own video' phrasing implicitly separates it from watch_link, though no sibling is named outright.

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 implied by the enumerated question types it answers, and 'Never download the video yourself' is a useful operational directive. However, it never says when not to use it or which sibling (watch_link, listen_score, read_notation_view) to prefer for adjacent needs.

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