set_language

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

With no annotations, the description carries the full burden. It explains that the override applies to specific note indices, that empty string resets to the group/track default, and implicitly that this modifies note language. It doesn't mention permissions or reversibility, but for a non-destructive language override, these are less critical. The explanation of the default language context adds useful behavioral insight.

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 two sentences, front-loaded with the verb and object, and every clause contributes: the use case, the scope, and the reset behavior. No filler or repetition.

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 4-parameter setter with no output schema and no annotations, the description is complete enough: it explains the purpose, the target, and the special reset case. Minor gaps remain about return value and interactions with existing overrides, but these are not significant for a well-scoped tool.

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 100%, so the baseline is 3. The tool description adds no new parameter meaning; 'Pass an empty string to reset' is already mirrored in the language parameter's description. The mention of 'given note indices' duplicates the indexes description. No extra semantic enrichment is provided 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 opens with a specific verb+resource: 'Set a per-note language override.' It clearly distinguishes from sibling tools like set_lyrics and set_phonemes by focusing on language, and provides a concrete example (English word inside Japanese lyrics) and reset behavior.

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 states when to use it: 'for mixed-language songs' and explains the empty-string reset path. It doesn't explicitly list when not to use it or alternatives, but the niche use case is clear. It could have explicitly contrasted with setting a group/track-wide language, but the group parameter semantics cover that.

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