library_value_summary

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It does add 'Read-only,' which communicates that no mutations occur. However, it doesn't disclose potential cost or latency of scanning the library, which would be valuable given the dry_run and scan_cap parameters suggest an expensive operation.

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 a single sentence, front-loaded with the tool's purpose, enumerates the report's components in a compact list, and ends with a useful read-only disclaimer. Every part earns its place with no wasted words.

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?

The description enumerates the report's key sections, which is especially helpful because there is no output schema to describe return values. It could add more operational context around scan cost or pagination, but those aspects are already hinted by dry_run and scan_cap parameters in 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?

Schema description coverage is 100%, so the parameters are fully documented in the schema itself. The description adds no additional parameter-specific meaning, matching the baseline of 3 with no penalty or bonus.

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 this tool produces a comprehensive report over the saved library and enumerates the exact contents (totals, runtime, counts, density, streaks, era histogram, lint counts, top artists). This distinguishes it from narrower sibling reports like duplicate_saved_versions or collab_density_report by positioning itself as a single aggregate 'mega-report.'

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 implies use when a holistic summary of the saved library is needed, but it does not explicitly state when to prefer this tool over alternatives or name any exclusions. With many similar reporting siblings available, explicit routing guidance is missing.

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