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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds real value beyond them by stating the call is free, requires no API key, and returns an exact (not estimated) figure – behavioral facts an agent cannot get from structured fields.

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?

Two tight sentences with zero waste: the core purpose is front-loaded and the auth/cost note follows immediately. Nothing could be cut without losing information.

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 simple quote tool with 100% param coverage and no output schema, the description covers purpose, pricing basis, and auth/cost behavior adequately. It stops short of describing the returned quote shape (single number vs breakdown), the only meaningful remaining gap.

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%, with rich enum descriptions for quality and defaults documented for width/height, so the schema does the heavy lifting. The description's 'from its length and resolution' only loosely maps the pricing inputs and 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 states a specific verb and resource: computing the exact USD price to restore one video clip, scoped by length and resolution. It distinguishes the tool from siblings like get_prices (general prices) and get_restore (job status) through the 'restore one video clip' framing, though it never names those alternatives explicitly.

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?

Usage is implied rather than stated: an agent can infer this is the pre-flight cost check before create_restore/start_restore, and 'Free, no key needed' usefully signals it can be called without auth or cost. However, there is no explicit when-to-use vs get_prices or create_restore guidance.

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