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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's value is the extra behavioral detail it adds: only published and reviewed videos are searchable, only the first 12 results carry signed scene images colored by narrative role, and the score means relevance rather than quality. It does not mention pagination via cursor, which is a remaining 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?

Four short sentences, scope stated first, then coverage, then result shape, then score semantics — well front-loaded with no filler. The mild overlap between 'main search for whole launch films' and 'finds ... launch videos' is the only redundancy.

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 and annotations cover safety, so the description doesn't need to explain return values, and it still helpfully flags the signed-image payload. However, for a 6-parameter, nested-filter, cursor-paginated search tool, the absence of any paging or sorting guidance leaves a real 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 description coverage is only 17% across six top-level parameters plus a large nested filters object, so the description has to compensate. It does map conceptually to several filters (description/query, brand, industry, timing, sound, style), but says nothing about sort, limit, cursor, or how the facet words map to actual field names.

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 opens with a specific verb and resource — 'Main search for whole launch films' — and enumerates the searchable facets (description, brand, industry, timing, sound, style). The 'whole launch films' phrasing implicitly separates it from scene-level siblings such as search_scenes and search_by_moment, so an agent can tell what it returns without opening the schema.

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?

'Main search' implies this is the primary entry point when starting a video-level lookup, but no sibling is named and no when-not condition is given. An agent must infer from purpose alone that scene-level needs belong elsewhere.

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