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

Annotations already declare readOnly and idempotent, so the bar is lower, and the description still adds real behavior: credits are reserved at creation, charged only on delivery, and the quote expires in 30 minutes. It also lists the return fields, which matters because there is no output schema. It stops short of covering idempotency semantics or what happens on quote reuse.

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?

Four tight sentences, front-loaded with purpose and return contents, then the quote-before-create rule and validity window. No filler, though the return-field list is the only mildly expendable clause.

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 tool with nested objects and no output schema, the description usefully compensates by naming the return values and explaining the reserve/charge lifecycle. The only remaining gap is how quote_id ties back into the create call, which the schema fields partially cover.

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 100% with detailed nested definitions (look modes, trim, aspect_ratios, metadata note "Quote and create with the same value"), so the schema carries parameter meaning. The description adds no parameter-level detail, making the baseline 3 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?

Specific verb (quote) plus resource (lyric video) and it explicitly frames itself as the pre-charge step before creation, which separates it from create_lyric_video. It does not name the near-sibling quote_canvas, so sibling differentiation relies on the resource name rather than an explicit callout.

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?

"Always quote first and tell the user the credits before creating" gives an explicit ordering condition for when to call this instead of creating directly. There is no when-not guidance or comparison to quote_canvas, but the workflow context is clear and actionable.

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