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

Goes beyond the annotations by disclosing that changing generation settings detaches the prior job from the project without deleting the job or its media, and that no credits are spent. This gives real substance to destructiveHint=true and idempotentHint=true. It doesn't explicitly address the overwrite semantics for fields omitted from the call, which is the one remaining gap.

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 verb and resource, then the behavioral consequence, then the use/do-not-use routing. No filler sentences and every clause carries information an agent needs.

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 an 8-parameter idempotent mutation with an output schema and full annotations, the description supplies the missing pieces: what gets detached, that no credits are spent, and the exclusion list. An agent could invoke this correctly from the definition alone.

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 75% and the schema already documents style, lyrics, model_id, duration_sec and instrumental well. The description's parenthetical field list (title, style, lyrics, instrumental, length, model) merely echoes parameter names and adds no format or constraint detail. Baseline 3 is appropriate.

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 and resource: overwrite the saved widget settings (title, style, lyrics, instrumental, length, model) on a prepared song before generating. That distinguishes it from generation and from prepare_song_project, though it never names the siblings directly. Clear and unambiguous overall.

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?

Explicit positive scope ("use this only to create a new song from a style description and optional lyrics") plus an enumerated negative list: covers, remixes, extending/editing, stem separation, voice cloning, transcription. The agent knows exactly which request routes here versus elsewhere.

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