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

Annotations only declare it is a safe, idempotent read. The description adds real behavioral context: Filimo lists reach ~200 titles and accept sort/country, Namava lists are fixed in newest or editorial order, 'upcoming' marks undated titles, and the 'kids' key expands into multiple rows rather than a single list.

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?

Front-loaded with the purpose, then sequencing, then provider-specific caveats — no filler. The middle sentence is dense and packs several unrelated facts (titles reach, ordering, upcoming flag, kids key) but each earns its place.

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 six-parameter read tool with no output schema, the description covers what comes back (titles plus refs usable by vod_title) and the provider-specific quirks an agent would otherwise discover by trial. Pagination limits and the exact return shape stay implicit, which is the only shortfall.

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%, so baseline is 3; the description still adds meaning beyond it by tying sort/country to Filimo only and noting sort does not apply to the kids age keys, plus the ~200-title reach that informs paging. It does not restate kind/page/limit, which the schema already covers.

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 concrete verb and resource ('Show the titles of one curated list on Filimo or Namava') with an example list, and implicitly contrasts with vod_collections, which supplies the key. An agent can distinguish it from vod_search/vod_browse without reading 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?

Gives an explicit pipeline: use after vod_collections, then vod_title with a returned ref. It also clarifies which sub-features apply where (sort/country only on Filimo). It stops short of saying when NOT to use it versus vod_browse or vod_featured, so not a 5.

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