YouTube MCP Server

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

With no annotations provided, the description carries full burden but lacks critical behavioral details. It mentions 'power feature' and default/max values, but does not disclose rate limits, authentication requirements, error conditions, or what the search returns (though output schema exists). For a search tool with no annotations, this leaves significant gaps in understanding operational constraints.

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 efficiently structured with a clear purpose statement followed by a well-organized Args section. Every sentence adds value: the first establishes scope, the second emphasizes utility, and the parameter explanations are necessary given 0% schema coverage. No wasted words or redundancy.

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 4 parameters with 0% schema coverage and an output schema (which handles return values), the description does well by explaining all parameters. However, as a search tool with no annotations, it should ideally mention performance expectations (e.g., search time) or limitations (e.g., transcript availability). The output schema reduces the need for return value explanation, but behavioral context remains light.

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 successfully explains all 4 parameters: channel (with URL/handle examples), query (text to search), language (preferred code with default), and max_videos (recent videos with default and max). This adds substantial meaning beyond the bare schema, though it could provide more detail on language code formats or channel input validation.

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 ('search for specific content'), resource ('across all videos of a YouTube channel'), and scope ('across all transcripts'), distinguishing it from siblings like search_transcript (single video) or search_videos (metadata). The phrase 'power feature: find what a creator said about any topic' further clarifies the unique value proposition.

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 clear context for when to use this tool ('search for specific content across all videos'), but does not explicitly state when not to use it or name alternatives. Sibling tools like search_transcript (single video) and search_videos (metadata) are implied alternatives, but not directly referenced in the description.

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