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

Annotations already declare readOnly, non-destructive, non-idempotent, open-world behavior, so the safety profile is covered. The description adds genuinely new behavioral context: the operation is free, the result is a draft requiring user approval, and how lines are split between two performers — details an agent cannot infer from annotations or schema.

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 tight sentences, front-loaded with the core action and output shape, then the workflow constraint, then the edge case. Nothing is redundant.

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?

With no output schema, the description usefully states the output is four lines and how to present them for approval. But it leaves the subject and occasion enums uninterpreted and gives no hint about what else the response contains, which matters for a five-parameter generative tool with zero schema descriptions.

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%, so the description must carry the burden. It correctly disambiguates two parameters: performer count maps to line assignment (1–2 = A, 3–4 = B) and 'a recipient is not another singer' prevents conflating recipient with a second performer. However, topic, subject, and occasion receive no explanation at all, leaving three of five parameters undocumented in both schema and description.

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?

Specific verb and resource: 'Write four short English rap lyric lines', with the 'for free' qualifier that separates this drafting step from the paid ordering siblings (create_character_video_order). An agent can tell immediately this produces draft text, not a video order.

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?

'Treat them as a draft: show the words and let the user approve or edit before ordering' establishes the workflow position — this is a preview step that precedes ordering. It gives clear context but names no explicit exclusion beyond the implicit 'do not order yet'.

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