youtube-mcp

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

With no annotations provided, the description carries full burden and adds valuable behavioral context: it discloses quota cost ('Costs 50 quota units'), partial update behavior ('Only provided fields are changed'), and clarifies that null values keep current settings. However, it doesn't mention permissions, rate limits, or error conditions that would be helpful for a mutation tool.

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 sized with a clear main sentence followed by structured parameter explanations. Every sentence earns its place, though the 'Args:' section formatting could be slightly more integrated with the main text.

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?

For a mutation tool with no annotations but an output schema, the description provides good coverage of the update operation, parameters, and behavioral traits. The quota cost disclosure is particularly valuable. It could be more complete by mentioning authentication requirements or error scenarios, but the presence of an output schema reduces the need to explain return values.

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?

With 0% schema description coverage, the description fully compensates by explaining all 6 parameters in detail, including their purposes and the meaning of null values ('or None to keep current'). This adds significant meaning beyond what the bare schema provides, especially for the nullable fields.

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 verb 'update' and resource 'video metadata', making the purpose specific and understandable. However, it doesn't explicitly differentiate from sibling tools like 'update_playlist' or 'set_thumbnail', which would require a 5.

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 modifying video metadata fields, but doesn't provide explicit guidance on when to use this versus alternatives like 'update_playlist' or 'set_thumbnail'. It mentions 'Only provided fields are changed' which offers some context, but lacks clear when/when-not rules or named alternatives.

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