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

Annotations already cover the safety profile (readOnly, openWorld, non-destructive), so the description adds real value by disclosing the billing model ($0.008 per page) and the shape of results (title, description, author, thumbnail, view metrics). It omits rate limits and pagination caps, keeping it short of a 5.

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 the core action front-loaded, followed by output and pricing. Every clause carries information, though the sort/date sentence partially duplicates schema content.

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?

With no output schema, the description usefully lists returned fields and covers cost, filtering, and sort. It is nearly complete for a search tool; only pagination behavior and any auth prerequisites are unaddressed.

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%, so all six parameters are already documented, including the enum and date formats. The description restates sort and date filtering but adds no syntax or semantic detail beyond the schema, matching the baseline.

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 and resource ('Search Facebook videos by keyword') and enumerates what comes back, which cleanly separates it from sibling search tools for posts, pages, and events. It stops short of naming an explicit alternative, but the resource scope is unambiguous.

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?

The description implies usage through its keyword-search framing and notes the date-range and sort options, but it never states when to prefer this over search_facebook_posts, facebook_page_videos, or search_youtube. Usage is implied rather than directed.

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