save_to_library

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

With no annotations provided, the description must carry the full behavioral burden. It discloses the max limit (40) and uses an example, but does not explain what happens on duplicate saves, error cases, or authentication requirements. Adequate but not thorough.

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?

The description is extremely concise: one sentence and a parameter list. The core action is front-loaded, and there is no unnecessary information. Every part earns its place.

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 simple nature of the tool and the presence of an output schema, the description is minimally adequate. However, it lacks details on error handling, idempotency, or which types of items can be saved (e.g., tracks only). Could be more complete for a robust agent.

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 0%, so the description must compensate. It adds an example format and a max limit, which is helpful, but it does not specify that URIs should be track URIs (as opposed to albums or shows) or mention URI validation. Partial but insufficient for full clarity.

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 'Save items to the current user's library', specifying the verb, resource, and destination. The example URI and max limit further clarify the action, and it distinguishes from siblings like remove_from_library and check_saved_in_library.

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 implies that this tool is for adding items to the user's library, but it does not explicitly provide guidance on when to use it versus alternatives like add_playlist_items or add_to_queue. No exclusions or prerequisites are mentioned.

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