Add media to an album

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

Annotations indicate a mutating operation, and the description adds meaningnful behavioral constraints beyond them: app-created media and album, the picked-item limitation, the save_to_library prerequisite, and the 50-item cap. This gives an agent a clear model of what the tool will and won't accept.

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?

Three short sentences, tightly packed with the essential constraint and limit. No redundant or filler content; the key usage rule is front-loaded.

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 mutating tool with no output schema, this description covers the important preconditions, the main exception, and the batch limit. It doesn't describe response or error behavior, but those are less critical and not indicated in annotations.

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 coverage is 100% and parameter descriptions are alraedy informative. The description adds extra semantic value by clarifying that album_id and media_item_ids must refer to app-created entities, and that picked media must be uploaded first, which is not captured in the schema.

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 and resource: adding media items to an album. Clearly distinguishes itself by emphasizing the app-created constraint on both sides, which differentiates it from operations like remove_from_album and create_album_with_media.

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?

Explicitly states when this tool applies: both the media items and the album must be app-created. It also gives an explicit exclusion and alternative: picked items cannot be added directly and must first be uploaded via save_to_library.

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