get_library_stats

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

The description accurately describes the output in both cases (item counts vs detailed stats), implying a read-only operation. No annotations are present, but the description is sufficiently transparent about behavior.

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?

The description is concise with two sentences that are front-loaded and every word adds value. No wasted or redundant information.

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?

Given the presence of an output schema, the description is complete enough: it covers the two modes of operation and the parameter semantics, leaving the output structure to the schema.

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 description adds significant meaning to the library_name parameter beyond the schema, explaining that omitting it returns all-library counts and including it returns detailed stats for that library. This compensates for the 0% schema description coverage.

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 clearly states the tool gets statistics for Plex libraries, and explains the difference between calling with and without the library_name parameter. This distinguishes it from sibling tools like get_libraries or get_library_contents.

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 description provides clear usage context by explaining the two modes based on the parameter, but does not explicitly state when not to use this tool or mention alternatives.

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