Scan library

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

Annotations declare readOnlyHint=false and destructiveHint=false but say nothing about why, and the description fills that gap precisely: it never modifies media files or metadata edits and never re-downloads metadata. It also discloses two behaviors invisible in the schema – the scan is asynchronous, and completion must be observed by polling list_libraries for a 'refreshing' state.

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 core action and scope, then safety, then the optional parameter, then async/polling. Every sentence carries information, though the parenthetical path hint and the polling instruction could be tightened into one clause without losing meaning.

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 two-parameter async action tool with no output schema, the description covers everything an agent needs: what it does, that it is safe despite write-like semantics, how to narrow scope, and how to verify completion. No important invocation detail is left to inference.

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 0%, so the description must carry the load, and it does for the non-obvious parameter: 'path' limits the scan to one server-side folder and points to get_item file.paths as the source of valid values. The required 'library' parameter is only implied by 'one library' – acceptable but the weaker half of the pair.

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 ('Trigger Scan Library Files') plus the resource scope ('one library') and the outcome ('Plex picks up added or removed files on disk'). No sibling tool does a scan, so the distinction is immediately clear from the name-plus-description pair.

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 the triggering condition ('picks up added or removed files on disk') and routes the agent to helpers for both pre- and post-steps (get_item file.paths for valid paths, list_libraries for polling 'refreshing'). It stops short of stating when a scan is unnecessary or which siblings to choose instead, so it is strong context rather than explicit when/when-not routing.

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