add_melody

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

With no annotations, the description carries the full burden; it does disclose meaningful behavioral detail in the melody grammar (PITCH:BEATS, r = rest) and the lyric-splitting rule. It says nothing about permissions, whether existing notes are overwritten, where the melody is placed relative to start_tick, or what is returned, so a mutation tool remains partially opaque.

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?

Front-loaded with the core action, then the format rules. The bilingual duplication is justified for a Japanese/English tool and each sentence carries format information rather than filler.

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 5-parameter mutation tool with no annotations and no output schema, the definition covers the tricky input formats well but omits part/start_tick/language semantics and any guidance on choosing this over the near-identical sibling. Adequate but with clear gaps.

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 0%, so the description must compensate. It gives rich format semantics for 'melody' and 'lyrics', but leaves 'part' (required), 'language' (default 'auto'), and 'start_tick' (default 0) entirely unexplained, so three of five parameters remain opaque.

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?

Names a specific verb + resource ('Add a melody with its lyrics in one call') and the phrase 'in one call' signals it is the combined alternative to adding a melody and then calling set_lyrics. It does not, however, distinguish itself from the confusingly similar ustx_add_melody sibling.

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?

Provides concrete usage rules for the lyrics portion (one lyric per sounding note, '+' for held syllables, split like set_lyrics), which tells the agent how to prepare input. It never states when to call this versus set_lyrics, add_notes, or ustx_add_melody, so selection guidance is only implied.

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