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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context by enumerating the side effects that are NOT performed (upload, generation, order, payment), which is exactly the kind of clarification annotations cannot express. It does not describe link lifetime or what the link resolves to, keeping it below a 5.

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?

Three short sentences, front-loaded with the return value and immediately followed by the negative scope clause, with no filler. Minor wording friction in "voice IDs mean female/male AI vocals", which could be phrased more directly, but nothing is wasted.

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 zero-required-parameter, no-output-schema tool, the description does state the return value (a link) and the no-side-effect guarantee. However, with 0% schema coverage it should explain what mood/style/story control and what the resulting link contains, leaving an agent to guess at three of five inputs.

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 0% across five parameters, so the description carries the burden and only partly discharges it. It meaningfully explains two of them (audio=story vs upload, and voice higher/lower mapping to female/male vocals), but leaves mood, style and the 600-character story field entirely uninterpreted beyond their enum values.

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 output ("Return a link with stage and song preferences prefilled"), which tells an agent this is a URL/draft builder rather than a generator. It is clear about what the tool does, but it never names or contrasts the siblings (list_stage_looks, get_product_info, get_singphoto_help), so differentiation relies on the agent's own inference.

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?

Gives real mode-selection guidance ("Use audio=story to describe a new AI song, or upload to bring an existing song") plus an explicit when-not clause: no upload, generation, order or payment happens here. It stops short of routing to an alternative tool for those excluded actions, so it is clear context without explicit alternatives.

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