playlistItems_insert

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

With no annotations, the description carries the full burden and does well by disclosing quota cost (50 units), OAuth requirement, and the conversion of startAt/endAt to ISO 8601 durations. It clearly implies a mutating operation (

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 three sentences, front-loaded with the core action, and then provides key behavioral details (quota, auth, time conversion). No fluff or repetition.

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?

Despite having 9 parameters and no output schema, the description covers essential operational context (auth, quota) and explicitly addresses the less-obvious startAt/endAt semantics. While it could mention error conditions or the response format, the schema descriptions cover the parameters well, and the description feels adequate for the complexity.

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%, so baseline is 3. The description adds value by explaining that startAt/endAt are in seconds and converted to ISO 8601 durations, which is not in the schema descriptions. It also reinforces the role of videoId and playlistId by naming them in the action.

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 'Add a video (videoId) to a playlist (playlistId)', which uses a specific verb and resource, and distinguishes it from sibling tools like playlistItems_update and playlistItems_delete by focusing on insertion. The mention of startAt/endAt also differentiates it as an add operation with timing.

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 usage for adding an item to a playlist but provides no explicit when-to-use versus alternatives or exclusions. It does not reference sibling tools or state conditions like 'do not use if the item already exists', leaving the context implicit.

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