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

Annotations already establish readOnlyHint=true, so the safety profile is covered. The description adds genuinely useful context beyond that: it names the fields returned and discloses that 'Library API keys are redacted', a security-relevant behavioral trait not visible in the schema.

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 dense sentence front-loads the verb and resource, then lists return contents, and ends with the API endpoint. Nothing is wasted, though the enumerated field list makes it slightly heavy for a one-line definition.

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?

With no output schema, the description usefully summarizes the returned fields, and annotations cover the read-only nature. Pagination and filtering are handled by the fully-described schema, so the agent has what it needs; only routing guidance against siblings is missing.

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 page, search, and per_page are fully documented in the schema with defaults and bounds. The description adds nothing about these parameters, so the baseline of 3 applies rather than a higher mark.

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 (List) and resource (Stream video libraries), and enumerates the data returned: video count, storage/traffic usage, linked pull/storage zones, player and encoding settings. This distinguishes it from the singular sibling bunny_get_video_library and from bunny_list_pull_zones or bunny_list_storage_zones.

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?

Usage is only implied by the verb 'List' – there is no explicit when-to-use guidance or statement of when to prefer this over bunny_get_video_library for a single library. The agent can infer the plural/singular split from the sibling names, but the description does not route it.

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