SunoMCP

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

With no annotations provided, the description carries the full burden. It successfully notes that the tool 'keeps the rest of the song unchanged' and returns a 'Task ID' (implying async behavior). However, it fails to clarify whether the operation is destructive (modifies original audio_id) or creates a new copy, and omits other behavioral traits like rate limits or generation time expectations.

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?

Excellent structure with zero waste: purpose statement first, behavioral clarification second, usage conditions in a bulleted list, and return value specification. Every sentence earns its place and is front-loaded appropriately.

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?

Given the presence of an output schema and 100% input schema coverage, the description adequately covers the tool's function. It appropriately mentions the Task ID return. Minor gap: does not clarify if the original audio is preserved or overwritten, which is relevant for a mutation operation.

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?

While the schema has 100% coverage (baseline 3), the description adds valuable semantic context beyond the schema: specifically mentioning 'section markers like [Verse], [Chorus]' for the lyric parameter, which helps the agent understand the expected format for that specific input.

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 precise action ('Replace a specific time range') and resource ('in a song'), clearly distinguishing this from sibling tools like extend_music or concat_music. The scope (time-based replacement vs. other operations) is immediately apparent.

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 'Use this when:' section provides explicit positive conditions (fixing sections, changing middle lyrics, replacing verses/choruses). However, it lacks explicit negative guidance or named alternatives (e.g., not mentioning when to use extend_music vs. replace).

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