similar_itemsFetch Plex's 'more like this' recommendations for a movie, show, or album by ratingKey, limited to your library, and filter by watched state to find similar unseen items in one call.
Plex's 'more like this' list for one item (movie, show, album…) by ratingKey, from your own library only. watched filters the results so 'similar but unseen' is one call.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| watched | No | all | |
| ratingKey | Yes |
Changes observed during successful MCP inspections.
v0.9.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare read-only, idempotent, closed-world behavior, so the safety profile is covered. The description's one added behavioral fact is the scope limit ('your own library only'), plus the idea that ordering comes from Plex's own recommendation engine rather than computed similarity; it says nothing about result shape, limit behavior, or failure on an invalid/unknown ratingKey.
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; the identity of the tool is front-loaded and the filtering note follows only because it adds a non-obvious capability. No filler or restatement of the name.
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 simple read tool with no output schema, the description covers what the call returns conceptually (a recommendation list) but omits the limit parameter's role and any indication of what an empty result or bad key looks like. Adequate to select the tool, thin on invocation detail.
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 parameter meaning. It explains watched well (filtering for unseen items) and identifies ratingKey as the item selector, but never mentions limit (default 10, max 50), leaving one of three parameters undocumented anywhere.
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?
Names a specific verb/resource: Plex's 'more like this' list for one item, addressed by ratingKey. The parenthetical (movie, show, album…) clarifies accepted item types, and 'from your own library only' separates it from a general discovery or search tool among the siblings.
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 clause 'watched filters the results so similar but unseen is one call' implies a concrete usage scenario, which is real guidance. But it never states when to prefer this over siblings like get_extras, get_children, or search, nor any prerequisites (e.g. whether the item must be in the library).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.