YouTube MCP Server

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. While it mentions what the tool returns, it doesn't cover important behavioral aspects like whether this is a read-only operation, potential rate limits, authentication requirements, error conditions, or pagination behavior. The description is minimal and lacks the depth needed for a tool with no annotation support.

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 appropriately concise with two clear sentences. The first sentence states the core functionality, and the second sentence specifies what information is returned. There's no wasted language or unnecessary elaboration. However, it could be slightly more structured by separating purpose from return values more explicitly.

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 that there are no annotations and no output schema, the description is insufficiently complete. For a search tool with 2 parameters, the description should provide more context about the search behavior, result format, limitations, and how it differs from the sibling 'playPlaylist' tool. The current description leaves too many behavioral questions unanswered.

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 schema description coverage is 100%, with both parameters well-documented in the schema itself. The description doesn't add any meaningful parameter information beyond what's already in the schema - it mentions 'by query' which is already covered by the schema's query parameter description. This meets the baseline expectation when schema coverage is complete.

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's purpose: 'Search for YouTube videos by query.' It specifies the verb (search) and resource (YouTube videos), and mentions the return fields (video IDs, titles, channels, descriptions). However, it doesn't explicitly differentiate from the sibling tool 'playPlaylist', which appears to serve a different function (playing playlists vs. searching videos).

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. It doesn't mention the sibling tool 'playPlaylist' or any other search-related tools that might exist. There's no context about when this search is appropriate or when other methods should be used instead.

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