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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, so the safety profile is covered. The description adds genuinely non-structured context: it is free, reserves nothing, and requires no buyer details, which is exactly the kind of side-effect information an agent needs. It does not describe the shape of the returned counts, but that is a minor gap.

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 core action and followed by cost/no-reservation guarantees and then the usage hint. No filler sentences.

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, read-only counting tool with no output schema, the description covers action, cost model, side effects, and intended workflow step. The only missing piece is what the returned counts look like, which is a modest gap given the straightforward read semantics.

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 67% and the tier/media_resolution fields are documented in detail in the schema itself, including pricing and defaults. The description only echoes 'fixed price' and 'filter set' without adding format, default, or interaction detail beyond what the schema already provides, so the baseline of 3 applies.

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 specific verb (count) and resource (clips and hours matching a filter set) scoped to a dataset tier, plus that a fixed price is attached. The closing clause 'before quoting' implicitly separates it from quote_training_dataset, though it never names that sibling 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?

'Use it to iterate on filters before quoting' gives a clear usage condition, and the free/no-reservation/no-buyer-details framing tells the agent this is the cheap exploratory step. It stops short of explicitly naming the alternative tools (quote_training_dataset, create_dataset_checkout) or stating when not to use it.

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