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

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered. The description adds real value beyond that: newest-first ordering, the media-type restriction, that the operation is free, and how the returned paths feed downstream tools. It does not cover pagination or result limits, which keeps it from a 5.

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?

Three compact sentences, front-loaded with what the tool does and what it returns, then the scope restriction, then the source-path integration hint. Every sentence earns its place with no filler.

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 parameterless read-only listing with no output schema, the description supplies the returned fields (path, size, change time), the ordering, the media-type filter, and the downstream usage of the paths — everything an agent needs to call and interpret it.

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 100%, so both limit and prefix are fully documented in the schema, including defaults and constraints. The description echoes the newest-first ordering but adds no syntax or format detail beyond the schema, so baseline 3 applies.

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 and resource (lists files in the account's library) plus the ordering (newest first) and the media-type scope (pictures, video, audio, fonts only). An agent can immediately tell this is the library enumeration tool and what it will return, with no sibling tool offering an equivalent listing operation.

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?

Explains where footage comes from and, crucially, that the returned path is the source argument for the clip and transcript tools — telling the agent when this tool is a useful precursor. It does not state when-not-to-use or name a competing alternative, so it stops short of a 5.

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