Retrieve a library

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile needs no restating. The description's only added context is that the target is an "external library" and the underlying endpoint, which is modest value beyond the structured data.

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?

Short and front-loaded, but the first line duplicates the tool title verbatim before the more informative second line, which is a small amount of wasted space.

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 single-parameter read with full annotation coverage this is close to sufficient, but with no output schema the description says nothing about what the returned library object contains, and it never routes the agent away from the list/statistics siblings.

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% and the single id parameter is documented as a UUID, so the schema carries the burden. "by its ID" merely restates the schema rather than adding format or lookup-origin details.

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 (Retrieve) and resource (a library), and adds the API mapping GET /libraries/{id}, so the operation is unambiguous. It does not, however, explicitly distinguish itself from siblings such as immich_get_all_libraries or immich_get_library_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?

"by its ID" implies this is single-item lookup keyed on an identifier, which weakly signals when to prefer it over immich_get_all_libraries. There is no explicit when-to-use guidance, no prerequisites, and no named alternative.

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