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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the description correctly spends its words elsewhere: the parity/scene-restriction quality guarantee, the exclusion of generated clips and fallbacks, and pagination behavior. It adds real information beyond the structured fields rather than restating the safety profile.

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 with no filler, and the actionable routing ('use journey_preview_generate.finishing') is placed early. Leading with an adjective-heavy qualifier rather than the action is mildly suboptimal front-loading, but nothing is wasted.

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?

An output schema exists, so return values need not be described, and annotations cover the safety profile; what remains for the description is scope, exclusions, and pagination, all of which are present. The only shortfall is that the tool's core action (enumerate styles) is implied rather than stated.

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 both parameters, and it does: 'Stable ID cursor pagination defaults to 50 entries, maximum 100' covers the limit default/ceiling and characterizes the cursor as a stable-ID cursor. It doesn't state what happens on an invalid or expired cursor, but the gap is small for a read-only catalog.

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 identifies the resource precisely (native transition styles with verified playback/export parity and scene restrictions) and rules out a confusing near-miss category ('Generated transition clips and fallbacks are never offered'). It never uses an explicit verb like 'list' or 'returns', so the agent infers from the catalogs_* naming that this is an enumeration tool rather than a lookup.

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 journey_preview_generate.finishing to apply an available style' hands the agent the downstream consumer, clearly splitting discovery from application. There is no guidance on when this catalog is the wrong choice versus other catalogs_* siblings, but the exclusion sentence narrows what the agent should expect to find here.

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