Add items to playlist

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

With no annotations, the description carries full burden for behavioral disclosure. It explains constraint about library and kind but fails to mention side effects (e.g., whether the operation is reversible, idempotent, requires permissions, or what the response looks like). For a mutation tool, this is insufficient transparency.

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, front-loaded with the core purpose, no filler. Every word 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?

The description covers the main constraint and purpose but does not mention what the tool returns (no output schema) or any additional behavioral details like error conditions or limits (max 500 items is only in schema). It is adequate for its simplicity but missing return value information.

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 description adds meaningful context beyond the input schema: it clarifies that all items must come from the playlist's library and that episode_id is conditionally required based on playlist kind. This helps an agent understand the relationship between parameters, especially since the items parameter itself lacks a top-level description (50% schema coverage).

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 verb 'appends' and the resources 'books or podcast episodes to a playlist,' directly distinguishing it from sibling tools like remove_items_from_playlist, create_playlist, or update_playlist.

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 provides an important constraint (entries must match the playlist's library and kind) but does not explicitly tell the agent when to use this tool versus alternatives like remove_items_from_playlist or create_playlist. The guidance is implied through context but not stated.

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