Create a library

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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false and openWorldHint=true, so the safety/mutation profile is covered structurally. The description adds only the fact that the library is 'external' (implying filesystem import paths) and the underlying POST endpoint; it says nothing about permissions, what the created library contains, or side effects.

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?

It is short and front-loaded with the action, but the title is restated verbatim as the first line before the actual sentence, and the 'Immich operation: POST /libraries · tag: Libraries' trailer is generator metadata rather than agent-useful content.

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 4-parameter write tool with no output schema, the annotations plus the schema cover most needs. However, the description never notes that ownerId is required, that the library is external/scan-backed, or how it relates to immich_scan_library, leaving gaps an agent would want filled.

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 all four parameters (name, ownerId, importPaths, exclusionPatterns) are already documented in the schema. The description adds no format, default, or constraint detail beyond what the schema provides, so the 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?

The description states a specific verb and resource ('Create a new external library'), and the 'external' qualifier distinguishes it from generic library concepts. It is clear enough to separate from the many other create_* siblings, though it never names update_library/delete_library to draw the boundary explicitly.

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?

There is no when-to-use guidance, no prerequisites (e.g., that a user/owner must exist), and no mention of the sibling tools that operate on the same resource (immich_update_library, immich_delete_library, immich_scan_library). The agent must infer usage purely from the name.

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