save_to_library

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

No annotations are provided, so the description carries the full burden. It mentions auto-chunking at 50 items, which is a useful behavioral detail. However, it does not disclose authentication needs, rate limits, idempotency, or error handling, leaving gaps.

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?

Two sentences with no wasted words. First sentence states purpose clearly. Second adds key behavioral detail (chunking) and parameter format. Front-loaded and efficient.

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 simple tool with one parameter and an output schema, the description covers core functionality and a behavioral detail. Lacks usage comparisons and error notes, but is mostly complete given the tool's simplicity.

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?

The input schema has 0% coverage (no parameter descriptions), but the description adds meaning by specifying URIs format with an example (e.g., 'spotify:track:xxx'). This is valuable beyond the schema alone, compensating for the lack of schema docs.

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 the action (save) and the resources (items to library) with specific types: tracks, albums, shows, episodes, audiobooks. This distinguishes it from siblings like remove_from_library or check_saved_in_library, which have different actions.

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 use cases by naming the resource (library) but does not explicitly state when to use this vs alternatives like add_playlist_items. It lacks guidance on when not to use it or prerequisites.

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