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

Annotations already flag non-read-only, destructive, and idempotent, and the description goes beyond them by explaining the financial behavior: credits are charged from the user's Deepnia balance, a failure is refunded, and the same quote_id never double-charges. That makes the destructiveHint and idempotentHint concrete rather than abstract.

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?

The when-to-use clause is front-loaded and every sentence carries information (trigger, charge source, refund, idempotency, next step). The single long sentence is slightly run-on, but 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?

For a two-parameter, credit-charging mutation with an output schema, the description covers the trigger, the billing and refund contract, the idempotency guarantee, and the required follow-up call — everything an agent needs to invoke it safely.

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 100% and both parameters are fully described there, so the baseline is 3. The description reinforces that credits is the price the user accepted and quote_id comes from quote_voiceover, but adds no syntax or format detail beyond the schema.

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 names a specific verb and resource ("makes the voice-over") and pins it to a concrete source (the quote_id and credits from quote_voiceover), which cleanly separates it from quote_voiceover (pricing) and the create_image/create_video siblings.

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?

It states the exact trigger condition — the user accepted the price from quote_voiceover — names the prerequisite tool, and prescribes the follow-up call to get_creation, so an agent knows both when to call it and what to do next.

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