youtube-mcp

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 adds useful context about quota cost ('Costs 1 quota unit'), which isn't in the schema, but doesn't cover other critical behaviors like pagination, error handling, or response format. It partially compensates for the lack of annotations.

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 front-loaded with the core purpose and cost, followed by parameter details in a structured 'Args:' section. It's efficient with minimal waste, though the parameter explanations could be slightly more integrated into the main text for better flow.

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's low complexity, 2 parameters, and the presence of an output schema (which handles return values), the description is reasonably complete. It covers purpose, cost, and parameters, but lacks usage guidelines and full behavioral context, leaving minor gaps for an agent.

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 explains both parameters: 'playlist_id' as the playlist ID and 'max_results' with its range and default value. This adds clear meaning beyond the bare schema, though it doesn't detail format constraints (e.g., playlist ID structure).

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 specific action ('List videos') and resource ('in a playlist'), distinguishing it from sibling tools like 'list_playlists' (which lists playlists) and 'list_channel_videos' (which lists videos from a channel). It precisely defines the tool's scope without ambiguity.

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 no guidance on when to use this tool versus alternatives like 'list_channel_videos' or 'search_videos', nor does it mention prerequisites such as authentication or playlist access. It lacks context for selection among similar listing tools.

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