Watchlist

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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so safety is covered. The description goes beyond them by disclosing the result shape (inLibrary flag, ratingKey presence/absence) and the ordering and pagination behavior, which an agent cannot get from annotations or the empty-coverage schema.

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 short sentences, front-loaded with what the tool returns, then the notable field semantics, then pagination. No filler and nothing repeated from the schema.

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 does the work of explaining the entry fields and null-ratingKey case, which is exactly what an agent needs to interpret results. Minor gaps remain around authentication as the server owner and the page-size ceiling.

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 the burden; it names both parameters and their pagination role ('paginate with offset/limit'), which is real added meaning. However it omits the default page size of 50, the maximum of 100, and that offset is measured in entries from the newest title.

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 with scope: the server owner's plex.tv watchlist, newest first. The read-only framing implicitly separates it from the sibling manage_watchlist, so an agent can tell which one mutates and which one lists.

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?

Usage is implied by the read-only listing nature rather than stated. It never explicitly says 'to add/remove use manage_watchlist' or defines when an agent should reach for this versus get_item or search, leaving the read/write routing to inference.

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