youtube_add_to_playlist

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does disclose one useful behavioral trait: duplicates are skipped during the add operation, and it suggests a preview/apply distinction. However, it does not explain what preview returns, whether apply modifies the playlist irreversibly, or any authentication/rate-limit requirements, leaving material gaps for a tool that mutates state.

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 a single concise sentence that front-loads the core operation and duplicates policy. Every word earns its place, with no redundancy or filler.

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 tool has no output schema and no annotations, the description is too sparse to be fully actionable. It leaves unexplained the exact expectations for 'input' and 'playlist', what the preview mode's result looks like, whether the new mode actually implies idempotency, and how errors or partial results are surfaced. An agent would need to guess or inspect runtime behavior.

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 maps 'video' to input and 'playlist' to playlist, and implies mode via 'preview or add', but it does not specify the input format (URL, video ID, search term), the playlist identifier format, or what values are valid for mode beyond the schema's enum. This is minimal added value over the raw 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?

The description clearly states the tool previews or adds one YouTube video to an existing playlist while skipping exact duplicates. The specific verb and resource combination ('add one YouTube video to an existing playlist') distinguishes it from siblings like youtube_check_playlist_duplicates, youtube_list_playlists, and youtube_create_playlist without needing to open their schemas.

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?

There is no explicit guidance about when to use this tool versus alternatives. It mentions a preview and apply mode, but does not state what conditions would favor this over e.g. youtube_save_track or youtube_check_playlist_duplicates, nor does it specify prerequisites like needing an existing playlist or how to identify it.

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