library-info

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

No annotations exist, so the description carries the full burden. It discloses that the tool only reads data and provides counts of specific entities, which implies non-destructive behavior. However, it does not mention response format, performance characteristics, or any limitations like large library handling.

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 sentence that effectively conveys the tool's purpose and output. No redundant or unnecessary information; every word contributes to clarity.

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 tool's simplicity (no output schema, single optional param), the description adequately covers what the tool does and what it returns (listed counts). It is complete enough for an agent to understand the tool's role among siblings, though it could briefly mention it's a quick summary overview.

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?

With 100% schema coverage (one parameter described), the description adds value by noting the default behavior: 'default: system Photos library'. This clarifies the optional parameter's fallback, which is not in the schema's description field alone.

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 retrieves high-level stats (counts) of various entities like photos, movies, albums, etc. It distinguishes from sibling tools like get-photo (individual item) and list-* tools (listing specific items) by focusing on summary statistics.

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 no guidance on when to use this tool vs alternatives. Despite having multiple sibling tools (export, get-photo, list-albums, etc.), there is no mention of situations where library-info is preferred or not.

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