Get extras

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

Annotations already cover read-only, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description adds genuinely non-obvious behavior: local extras carry file paths while Plex streaming trailers return an empty paths value, which prevents misreading results as missing data.

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?

Two tight sentences with no filler; the contents enumeration comes first and the paths caveat follows logically. Every clause 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?

With no output schema, the description sensibly discloses the one result nuance an agent would trip over (empty paths for streaming trailers). It is adequate for a single-parameter read tool, though a note on where ratingKey comes from would close the last 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?

The single parameter has 0% schema description coverage, so the description carries the burden. It tells the agent the key identifies one item, but does not explain what a ratingKey is or where to obtain it (e.g., from list_media or get_item), leaving a real gap.

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 names the resource precisely and enumerates its contents (trailers, featurettes, behind-the-scenes, deleted scenes), which makes it unmistakable versus siblings like get_children or get_item. It does not explicitly contrast itself with a sibling, so it stops short of a 5.

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?

'for one item by ratingKey' implies you need a known item key, giving implicit context for use. But there is no explicit when-to-use guidance, no mention of how this relates to get_children or get_item, and no exclusions, so the agent must infer the routing decision.

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