library_stats

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

With no annotations, the description carries the full burden. It explicitly says 'Get statistics,' indicating a read-only operation, and enumerates the outputs, but does not disclose behaviors like error handling when no library is loaded, performance implications, or whether the stats are computed on the fly. This is a basic transparency level but not comprehensive.

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?

A single, front-loaded sentence that immediately states the tool's purpose and then lists the specific statistics. Every word earns its place, with no filler or redundancy.

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 no-parameter tool, the description lists the output categories, but the lack of usage context (e.g., when to choose this over sibling analytics tools) and missing behavioral details (e.g., reliance on a loaded library) leave gaps. The output format is not described, but the listed stats provide a reasonable mental model.

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 tool takes zero parameters, so per the rubric the description does not need to add parameter-level details. The description focuses on what statistics are returned, which is the salient semantic information for this parameterless tool.

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 'Get statistics about the loaded library' with a specific verb and resource, and lists the exact types of statistics (track count, genre distribution, BPM range, key distribution). This distinguishes it from session-history siblings like dj_getHistoryStats and dj_getPlayCountAnalytics, though it doesn't explicitly name alternatives.

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?

No guidance is provided on when to use this tool versus alternatives. There is no mention of prerequisites (e.g., library must be loaded) or exclusions. The description implies a read-only overview, but does not help the agent decide between library_stats and other statistics tools.

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