ustx_add_notes

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

With no annotations, the description carries the full behavioral burden, and it does disclose one genuine trait: the target part is auto-extended when notes exceed its current length. It says nothing about whether the file is written in place, what happens if the path or part index is invalid, or what is returned, which leaves meaningful gaps for a mutation 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 tight sentence (duplicated in Japanese) that front-loads the action and appends the side effect. No filler, though the bilingual duplication doubles length without adding new information for a single-language reader.

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?

For a three-parameter, fully required mutation tool with no annotations and no output schema, the description should say more about preconditions and effects. It covers the auto-extension behavior but omits file-existence requirements, overwrite/conflict behavior at the target ticks, and any indication of the result.

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?

Top-level schema coverage is 0% (path, part, and notes have bare titles), but the description compensates partially by establishing that path is a .ustx file and part is a voice part, while the nested NoteIn fields are already well documented in the schema. It does not clarify whether part is an index or a name, nor the position/duration units at the top level.

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 concrete verb and resource: add notes to a voice part in a .ustx file, plus the scope caveat that the part grows as needed. That distinguishes it reasonably well from sibling operations like ustx_add_melody or ustx_edit_notes, though it never explicitly contrasts itself with them.

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?

There is no when-to-use or when-not-to-use guidance and no named alternative. The agent must infer from the name alone whether this or ustx_add_melody, add_notes, or ustx_edit_notes is the right call, and no prerequisites (existing .ustx file, existing part index) are stated.

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